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www.ti.com production data information is current as of publication date. products conform to specifications per the terms of texas instruments standard warranty. production processing does not necessarily include testing of all parameters. copyright ?2001-2004, texas instruments incorporated please be aware that an important notice concerning availability, standard warranty, and use in critical applications of texas instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. features 4-wire touch screen interface and 4-by-4 keypad interface ratiometric conversion single 2.7v to 3.6v supply serial interface internal detection of screen touch and keypad programmable 8-, 10-, or 12-bit resolution programmable sampling rates direct battery measurement (0.5v to 6v) on-chip temperature measurement touch-pressure measurement full power-down control tssop-28 and qfn-32 packages applications personal digital assistants cellular phones mp3 players pda analog interface circuit description the TSC2200 is a complete pda analog interface circuit. it contains a complete 12-bit, analog-to-digital (a/d) resistive touch screen converter including drivers, the control to mea- sure touch pressure, keyboard controller, and an 8-bit digital- to-analog (d/a) converter output for lcd contrast control. the TSC2200 interfaces to the host controller through a standard spi serial interface. the TSC2200 offers program- mable resolution and sampling rates from 8- to 12-bits and up to 125khz to accommodate different screen sizes. the TSC2200 also offers two battery-measurement inputs capable of reading battery voltages up to 6v, while operating at only 2.7v. it also has an on-chip temperature sensor capable of reading 0.3 c resolution. the TSC2200 is available in a tssop-28 and a qfn-32 package. TSC2200 sbas191f ?february 2001 ?revised april 2004 spi is a registered trademark of motorola. us patent no. 624639. a/d converter internal 2.5v reference mux serial interface and control logic d/a converter miso ss sclk mosi dav penirq kbirq touch panel drivers temp sensor battery monitor battery monitor x+ x y+ y v bat1 v bat2 clock aux1 aux2 v ref arng a out keyboard scanner and state control c1 c2 c3 c4 r1 r2 r3 r4 t s c 2 2 0 0 t s c 2 2 0 0
2 www.ti.com TSC2200 sbas191f absolute maximum ratings (1) v dd to gnd ........................................................................ 0.3v to +6.0v v bat input voltage to gnd ............................................... 0.3v to +6.0v analog input voltage to gnd (except v bat ) ........... 0.3v to v dd + 0.3v digital input voltage to gnd ................................... 0.3v to v dd + 0.3v operating temperature range ...................................... 40 c to +105 c storage temperature range ......................................... 65 c to +150 c junction temperature (t j max) .................................................... +150 c tssop package power dissipation .................................................... (t j max t a )/ ja ja thermal impedance .......................................................... 90 c/w lead temperature, soldering vapor phase (60s) ............................................................ +215 c infrared (15s) ..................................................................... +220 c note: (1) stresses above those listed under absolute maximum ratings may cause permanent damage to the device. exposure to absolute maximum conditions for extended periods may affect device reliability. integral specified linearity package temperature package ordering transport product error (lsb) package-lead designator (1) range marking number media, quantity TSC2200 2 tssop-28 pw 40 c to +85 c TSC2200i TSC2200ipw rails, 50 "" " " " " TSC2200ipwr tape and reel, 2000 TSC2200 2 qfn-32 rhb 40 c to +85 c TSC2200i TSC2200irhb tubes, 72 "" " " " " TSC2200irhbr tape and reel, 2500 note: (1) for the most current specifications and package information, refer to our web site at www.ti.com. electrostatic discharge sensitivity this integrated circuit can be damaged by esd. texas instruments recommends that all integrated circuits be handled with appropriate precautions. failure to observe proper han- dling and installation procedures can cause damage. esd damage can range from subtle performance degrada- tion to complete device failure. precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. timing diagram all specifications typical at 40 c to +85 c, +v dd = +2.7v. t td t lag t dis t lead t sck t wsck t wsck t hi t su t ho t a t v t r t f ss sclk msb out msb in lsb in lsb out bit 6 ... 1 bit 6 ... 1 miso mosi parameter conditions min typ max units sclk period t sck 30 ns enable lead time t lead 15 ns enable lag time t lag 15 ns sequential transfer delay t td 30 ns data setup time t su 10 ns data hold time (inputs) t hi 10 ns data hold time (outputs) t ho 0ns slave access time t a 15 ns slave d out disable time t dis 15 ns data valid t v 10 ns rise time t r 30 ns fall time t f 30 ns timing characteristics (1)(2) at 40 c to +85 c, +v dd = +2.7v, v ref = +2.5v, unless otherwise noted. TSC2200 notes: (1) all input signals are specified with t r = t f = 5ns (10% to 90% of v dd ) and timed from a voltage level of (v il + v ih )/2. (2) see timing diagram below.
3 www.ti.com TSC2200 sbas191f electrical characteristics at 40 c to +85 c, +v dd = +2.7v, internal v ref = +2.5v, conversion clock = 2mhz, and 12-bit mode, unless otherwise noted. TSC2200ipw TSC2200irhb parameter conditions min typ max min typ max units auxiliary analog input input voltage range 0 +v ref ?? v input capacitance 25 ? pf input leakage current 1 ? a battery monitor input input voltage range 0.5 6.0 ?? v input capacitance 25 ? pf input leakage current 1 ? a accuracy 3+3 ?? % temperature measurement temperature range 40 +85 ?? c temperature resolution 0.3 ? c accuracy 2 ? c a/d converter resolution programmable: 8-, 10-, or 12-bits 12 ? bits no missing codes 12-bit resolution 11 ? bits integral linearity 2 3lsb offset error 6 ? lsb gain error excluding reference error 6 ? lsb noise 30 ? vrms power-supply rejection 80 ? db d/a converter output current range set by resistor from arng to gnd 650 500 a resolution 8 ? bits integral linearity 2 ? lsb voltage reference voltage range internal 2.5v 2.45 2.5 2.55 ??? v internal 1.25v 1.225 1.25 1.275 ?? 1.285 v reference drift 20 ? ppm/ c external reference input range 1.0 v dd ?? v current drain 20 ? a digital input/output internal clock frequency 8 ? mhz logic family cmos ? logic levels: v ih i ih = +5 a0.7v dd ? v v il i il = +5 a 0.3 0.3v dd ?? v v oh i oh = 2 ttl loads 0.8v dd ? v v ol i ol = 2 ttl loads 0.4 ? v power-supply requirements power-supply voltage, +v dd specified performance 2.7 3.6 ?? v quiescent current see note (1) 1.25 2.3 ? 2.5 ma see note (2) 500 ? a power-down 3 ? a temperature range specified performance 40 +85 ?? c ? specifications same as TSC2200ipw. notes: (1) aux1 conversion, no averaging, no ref power down, 50 s conversion. (2) aux1 conversion, no averaging, external reference , 50 s conversion.
4 www.ti.com TSC2200 sbas191f pin description pin tssop qfn name description 1 29, 30 v dd power supply 2 31 x+ x+ position input 3 32 y+ y+ position input 41x x position input 52y y position input 6 3 gnd ground 74v bat1 battery monitor input 1 85v bat2 battery monitor input 2 96v ref voltage reference input/output 10 7 kbirq keyboard interrupt (active low) 11 8 r1 row 1 12 10 r2 row 2 13 11 r3 row 3 14 12 r4 row 4 15 13 c1 column 1 16 14 c2 column 2 17 15 c3 column 3 18 16 c4 column 4 19 17 sclk serial clock input 20 18 ss slave select input (active low). data will not be clocked in to mosi unless ss is low. when ss is high, miso is high impedance. 21 19 mosi serial data input. data is clocked in at sclk falling edge. 22 20 dav data available (active low) 23 21 miso serial data output. data is clocked out at sclk falling edge. high impedance when ss is high. 24 22 penirq pen interrupt 25 23 a out analog output current from d/a converter 26 26 arng d/a converter analog output range set 27 27 aux2 auxiliary a/d converter input 2 28 28 aux1 auxiliary a/d converter input 1 9, 24, 25 nc no connection pin configuration top view tssop +v dd x+ y+ x y gnd v bat1 v bat2 v ref kbirq r1 r2 r3 r4 aux1 aux2 arng a out penirq miso dav mosi ss sclk c4 c3 c2 c1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 TSC2200 top view qfn x y gnd v bat1 v bat2 v ref kbirq r1 nc a out penirq miso dav mosi ss sclk 1 2 3 4 5 6 7 8 24 23 22 21 20 19 18 17 TSC2200 y+ x+ v dd v dd aux1 aux2 arng nc 32 31 30 29 28 27 26 25 nc r2 r3 r4 c1 c2 c3 c4 9 10 11 12 13 14 15 16
5 www.ti.com TSC2200 sbas191f typical characteristics at t a = +25 c, +v dd = +2.7v, conversion clock = 2mhz, 12-bit mode, and v ref = +2.5v, unless otherwise noted. conversion supply current vs temperature 0 60 100 40 20 20 temperature ( c) i dd (ma) 1.86 1.85 1.84 1.83 1.82 1.81 1.80 1.79 1.78 40 60 80 power-down supply current vs temperature 20 40 100 20 0 40 temperature ( c) i dd (na) 10 8 6 4 2 0 60 80 power-down supply current vs supply voltage 3.1 2.7 3.7 3.3 supply voltage (v) supply current (na) 0.30 0.25 0.20 0.15 0.10 0.05 0 3.5 2.9 internal oscillator frequency vs v dd 3.1 2.5 3.7 2.7 3.3 v dd (v) frequency (mhz) 8.7 8.6 8.5 8.4 8.3 8.2 8.1 3.5 2.9 change in gain error vs temperature 0 60 100 40 20 20 temperature ( c) change in gain error (lsb) 0.5 0.4 0.3 0.2 0.1 0 0.1 0.2 0.3 0.4 0.5 40 60 80 change in offset error vs temperature 0 60 100 40 20 20 temperature ( c) change in offset (lsb) 40 60 80 0.5 0.4 0.3 0.2 0.1 0 0.1 0.2 0.3 0.4 0.5
6 www.ti.com TSC2200 sbas191f typical characteristics (cont.) at t a = +25 c, +v dd = +2.7v, conversion clock = 2mhz, 12-bit mode, and v ref = +2.5v, unless otherwise noted. internal reference vs temperature 20 40 60 100 40 20 0 60 80 temperature ( c) v ref (v) 2.55 2.54 2.53 2.52 2.51 2.50 2.49 2.48 2.47 2.46 2.45 v ref (v) 1.275 1.270 1.265 1.260 1.255 1.250 1.245 1.240 1.235 1.230 1.225 2.5v reference 1.25v reference internal reference vs v dd 3.3 3.5 2.5 3.7 2.7 2.9 3.1 v dd (v) v ref (v) 2.55 2.54 2.53 2.52 2.51 2.50 2.49 2.48 2.47 2.46 2.45 v ref (v) 1.275 1.270 1.265 1.260 1.255 1.250 1.245 1.240 1.235 1.230 1.225 2.5v reference 1.25v reference internal oscillator frequency vs temperature 0 60 100 40 20 20 temperature ( c) frequency (mhz) 8.8 8.6 8.4 8.2 8.0 7.8 7.6 7.4 40 60 80 touch screen driver on-resistance vs temperature 0 60 100 40 20 20 temperature ( c) resistance ( ? ) 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 40 60 80 switch-on resistance vs v dd 3.1 2.5 3.7 2.7 3.3 supply voltage (v) resistance ( ? ) 6.2 6.1 6.0 5.9 5.8 5.7 5.6 5.5 5.4 5.3 3.5 2.9 temp1 diode voltage vs temperature 0 60 100 40 20 20 temperature ( c) voltage (mv) 800 750 700 650 600 550 500 450 400 40 60 80
7 www.ti.com TSC2200 sbas191f typical characteristics (cont.) at t a = +25 c, +v dd = +2.7v, conversion clock = 2mhz, 12-bit mode, and v ref = +2.5v, unless otherwise noted. 900 800 700 600 500 voltage (mv) temperature ( c) 60 40 20 0 20 40 60 80 100 temp2 diode voltage vs temperature temp1 diode voltage vs supply voltage 3.1 2.5 3.7 2.7 3.3 v dd (v) diode voltage (mv) 612.0 611.8 611.6 611.4 611.2 611.0 610.8 610.6 610.4 610.2 610.0 3.5 2.9 temp2 diode voltage vs supply voltage 3.1 2.5 3.7 2.7 3.3 v dd (v) diode voltage (mv) 727.06 727.04 727.02 727.00 727.98 727.96 727.94 727.92 727.90 3.5 2.9 dac output current vs temperature 0 60 100 40 20 20 temperature ( c) current (ma) 1.00 0.95 0.90 0.85 0.80 0.75 0.70 0.65 0.60 40 60 80 dac max current vs v dd 3.1 2.5 3.7 2.7 3.3 v dd (v) current (ma) 0.895 0.890 0.885 0.880 0.875 0.870 0.865 0.860 0.855 3.5 2.9
8 www.ti.com TSC2200 sbas191f figure 1. typical circuit configuration. overview the TSC2200 is an analog interface circuit for human inter- face devices. a register-based architecture eases integration with microprocessor-based systems through a standard spi bus. all peripheral functions are controlled through the reg- isters and onboard state machines. the TSC2200 consists of the following blocks (refer to the block diagram on the front page): touch screen interface keypad interface battery monitors auxiliary inputs temperature monitor current output d/a converter communication to the TSC2200 is via a standard spi serial interface. this interface requires that the slave select signal be driven low to communicate with the TSC2200. data is then shifted into or out of the TSC2200 under control of the host microprocessor, which also provides the serial data clock. control of the TSC2200 and its functions is accomplished by writing to different registers in the TSC2200. a simple com- mand protocol is used to address the 16-bit registers. reg- isters control the operation of the a/d converter, d/a con- verter, and keypad scanner. the result of measurements made will be placed in the TSC2200 s memory map and may be read by the host at any time. three signals are available from the TSC2200 to indicate that data is available for the host to read. the dav output indicates that an a/d conversion has completed and that data is available. the kbirq output indicates that a key on the keypad has been pressed. the penirq output indicates that a touch has been detected on the touch screen. a typical application of the TSC2200 is shown in figure 1. + auxiliary input auxiliary input pen interrupt request serial data out data available serial data in slave select serial clock 1 f to 10 f (optional) +2.7v to +3.3v touch screen 0.1 f +v dd x+ y+ x y gnd v bat1 v bat2 v ref kbirq r1 r2 r3 r4 aux1 aux2 arng a out penirq miso dav mosi ss sclk c4 c3 c2 c1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 TSC2200ipw + 1 f to 10 f (optional) 0.1 f main battery secondary battery keypad keyboard interrupt request lcd contrast voltage regulator rrng
9 www.ti.com TSC2200 sbas191f figure 2. 4-wire touch screen construction. figure 3. pressure measurement. operation touch screen a resistive touch screen works by applying a voltage across a resistor network and measuring the change in resistance at a given point on the matrix where a screen is touched by an input stylus, pen, or finger. the change in the resistance ratio marks the location on the touch screen. the TSC2200 supports the resistive 4-wire configurations (see figure 1). the circuit determines location in two coordi- nate pair dimensions, although a third dimension can be added for measuring pressure. the 4-wire touch screen coordinate pair measurement a 4-wire touch screen is constructed as shown in figure 2. it consists of two transparent resistive layers separated by insulating spacers. the 4-wire touch screen panel works by applying a voltage across the vertical or horizontal resistive network. the a/d converter converts the voltage measured at the point the panel is touched. a measurement of the y-position of the pointing device is made by connecting the x+ input to a data converter chip, turning on the y+ and y drivers, and digitizing the voltage seen at the x+ input. the voltage measured is determined by the voltage divider developed at the point of touch. for this measurement, the horizontal panel resistance in the x+ lead does not affect the conver- sion due to the high input impedance of the a/d converter. voltage is then applied to the other axis, and the a/d converter converts the voltage representing the x-position on the screen. this provides the x- and y-coordinates to the associated processor. measuring touch pressure (z) can also be done with the TSC2200. to determine pen or finger touch, the pressure of the touch needs to be determined. generally, it is not necessary to have very high performance for this test, there- fore, the 8-bit resolution mode is recommended (however, calculations will be shown with the 12-bit resolution mode). there are several different ways of performing this measure- ment. the TSC2200 supports two methods. the first method requires knowing the x-plate resistance, measurement of the x-position, and two additional cross panel measurements (z 2 and z 1 ) of the touch screen, as seen in figure 3. using equation 1 will calculate the touch resistance: rr x-position 4096 z z 1 touch x-plate 2 1 = ? ? ? ? ? ? ? (1) the second method requires knowing both the x-plate and y-plate resistance, measurement of x-position and y-posi- tion, and z 1 . using equation 2 will also calculate the touch resistance: (2) rr x position z r y position touch x plate y plate =? ? ? ? ? ? ? ? ??? ? ? ? ? ? ? -- -- 4096 4096 11 4096 1 when the touch panel is pressed or touched, and the drivers to the panel are turned on, the voltage across the touch panel will often overshoot and then slowly settle (decay) down to a stable dc value. this is due to mechanical bouncing which is caused by vibration of the top layer sheet of the touch panel when the panel is pressed. this settling time must be accounted for, or else the converted value will be in error. therefore, a delay must be introduced between the time the driver for a particular measurement is turned on, and the time measurement is made. conductive bar insulating material (glass) silver ink transparent conductor (ito) bottom side transparent conductor (ito) top side x+ x y+ y ito = indium tin oxide x-position measure x-position measure z 1 -position touch x+ y+ x y z 1 -position touch x+ y+ y x measure z 2 -position z 2 -position touch x+ y+ y x
10 www.ti.com TSC2200 sbas191f figure 4. simplified diagram of the analog input section. converter ref +ref +in in v bat1 aux1 battery on aux2 gnd 2.5v reference ref on/off x+ x +v dd temp1 y+ y v ref temp0 7.5k ? v bat2 7.5k ? 2.5k ? battery on 2.5k ? in some applications, external capacitors may be required across the touch screen for filtering noise picked up by the touch screen; i.e., noise generated by the lcd panel or back-light circuitry. the value of these capacitors will provide a low-pass filter to reduce the noise, but will cause an additional settling time requirement when the panel is touched. several solutions to this problem are available in the TSC2200. a programmable delay time is available that sets the delay between turning the drivers on and making a conversion. this is referred to as the panel voltage stabilization time, and is used in some of the modes available in the TSC2200. in other modes, the TSC2200 can be commanded to turn on the drivers only without performing a conversion. time can then be allowed before a conversion is started. the TSC2200 touch screen interface can measure position (x and y) and pressure (z). determination of these coordinates is possible under three different modes of the a/d converter: conversion controlled by the TSC2200, initiated by detection of a touch; conversion controlled by the TSC2200, initiated by the host responding to the penirq signal; or conversion completely controlled by the host processor. a/d converter the analog inputs of the TSC2200 are shown in figure 4. the analog inputs (x, y, and z touch panel coordinates, battery voltage monitors, chip temperature, and auxiliary inputs) are provided via a multiplexer to the successive approximation register (sar) a/d converter. the a/d converter architecture is based on capacitive redistribution architecture that inher- ently includes a sample-and-hold function.
11 www.ti.com TSC2200 sbas191f figure 5. ideal input voltages and output codes. figure 6. penirq functional block diagram. output code 0v fs = full-scale voltage = v ref (1) 1lsb = v ref (1) /4096 fs 1lsb 11...111 11...110 11...101 00...010 00...001 00...000 1lsb notes: (1) reference voltage at converter: +ref ( ref). see figure 4. (2) input voltage at converter, after multiplexer: +in ( in). see figure 4. input voltage (2) (v) v dd v dd 50k ? on y+ or x+ drivers on, or temp1, temp2 measurements activated y+ x+ y high except when temp1, temp2 activated penirq temp2 temp1 temp diode a unique configuration of low on-resistance switches allows an unselected a/d converter input channel to provide power and an accompanying pin to provide ground for driving the touch panel. by maintaining a differential input to the con- verter and a differential reference input architecture, it is possible to negate errors caused by the driver switch on- resistances. the a/d converter is controlled by an a/d converter control register. several modes of operation are possible, depend- ing upon the bits set in the control register. channel selec- tion, scan operation, averaging, resolution, and conversion rate may all be programmed through this register. these modes are outlined in the sections below for each type of analog input. the results of conversions made are stored in the appropriate result register. data format the TSC2200 output data is in straight binary format, as shown in figure 5. this figure shows the ideal output code for the given input voltage and does not include the effects of offset, gain, or noise. reference the TSC2200 has an internal voltage reference that can be set to 1.25v or 2.5v, through the reference control register. the internal reference voltage is only used in the single- ended mode for battery monitoring, temperature measure- ment, and for utilizing the auxiliary inputs. optimal touch screen performance is achieved when using a ratiometric conversion, thus all touch screen measurements are done automatically in the differential mode. an external reference can also be applied to the v ref pin, and the internal refer- ence can be turned off. variable resolution the TSC2200 provides three different resolutions for the a/d converter: 8-, 10-, or 12-bits. lower resolutions are often practical for measurements such as touch pressure. perform- ing the conversions at lower resolutions reduces the amount of time it takes for the a/d converter to complete its conversion process, which lowers power consumption. conversion clock and conversion time the TSC2200 contains an internal 8mhz clock, which is used to drive the state machines inside the device that perform the many functions of the part. this clock is divided down to provide a clock to run the a/d converter. the division ratio for this clock is set in the a/d converter control register. the ability to change the conversion clock rate allows the user to choose the optimal value for resolution, speed, and power. if the 8mhz clock is used directly, the a/d converter is limited to 8-bit resolution; using higher resolutions at this speed will not result in accurate conversions. using a 4mhz conversion clock is suitable for 10-bit resolution; 12-bit resolution requires that the conversion clock run at 1mhz or 2mhz. regardless of the conversion clock speed, the internal clock will run nominally at 8mhz. the conversion time of the TSC2200 is dependent upon several functions. although the conversion clock speed plays an important role in the time it takes for a conversion to complete, a certain number of internal clock cycles is needed for proper sampling of the signal. moreover, additional times, such as the panel voltage stabilization time, can add significantly to the time it takes to perform a conversion. conversion time can vary depending upon the mode in which the TSC2200 is used. throughout this data sheet, internal and conversion clock cycles will be used to describe the times that many functions take. in considering the total system design, these times must be taken into account by the user. touch detect the pen interrupt ( penirq ) output function is detailed in figure 6. while in the power-down mode, the y driver is on and connected to gnd and the penirq output is connected to the x+ input. when the panel is touched, the x+ input is
12 www.ti.com TSC2200 sbas191f msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 r/w pg3 pg2 pg1 pg0 addr5 addr4 addr3 addr2 addr1 addr0 x x x x x table i. TSC2200 command word. pg3 pg2 pg1 pg0 page addressed 0000 0 0001 1 0 0 1 0 reserved 0 0 1 1 reserved 0 1 0 0 reserved 0 1 0 1 reserved 0 1 1 0 reserved 0 1 1 1 reserved 1 0 0 0 reserved 1 0 0 1 reserved 1 0 1 0 reserved 1 0 1 1 reserved 1 1 0 0 reserved 1 1 0 1 reserved 1 1 1 0 reserved 1 1 1 1 reserved table ii. page addressing. pulled to ground through the touch screen and penirq output goes low due to the current path through the panel to gnd, initiating an interrupt to the processor. during the measurement cycles for the x- and y-positions, the x+ input will be disconnected from the penirq pull-down transistor to eliminate any leakage current from the pull-up resistor to flow through the touch screen, thus causing no errors. in modes where the TSC2200 needs to detect if the screen is still touched (for example, when doing a penirq -initiated x, y, and z conversion), the TSC2200 must reset the drivers so that the 50k ? resistor is connected again. due to the high value of this pull-up resistor, any capacitance on the touch screen inputs will cause a long delay time, and may prevent the detection from occurring correctly. to prevent this, the TSC2200 has a circuit that allows any screen capacitance to be precharged , so that the pull-up resistor does not have to be the only source for the charging current. the time allowed for this precharge, as well as the time needed to sense if the screen is still touched, can be set in the configuration control register. this illustrates the need to use the minimum capacitor values possible on the touch screen inputs. these capacitors may be needed to reduce noise, but too large a value will increase the needed precharge and sense times, as well as panel voltage stabilization time. digital interface the TSC2200 communicates through a standard spi bus. the spi allows full-duplex, synchronous, serial communica- tion between a host processor (the master) and peripheral devices (slaves). the spi master generates the synchroniz- ing clock and initiates transmissions. the spi slave devices depend on a master to start and synchronize transmissions. a transmission begins when initiated by a master spi. the byte from the master spi begins shifting in on the slave mosi pin under the control of the master serial clock. as the byte shifts in on the mosi pin, a byte shifts out on the miso pin to the master shift register. the idle state of the serial clock for the TSC2200 is low, which corresponds to a clock polarity setting of 0 (typical microprocessor spi control bit cpol = 0). the TSC2200 interface is designed so that with a clock phase bit setting of 1 (typical microprocessor spi control bit cpha = 1), the master begins driving its mosi pin and the slave begins driving its miso pin on the first serial clock edge. the ss pin should idle high between transmissions. the TSC2200 will only interpret command words that are transmitted after the falling edge of ss . TSC2200 communication protocol the TSC2200 is entirely controlled by registers. reading and writing these registers is accomplished by the use of a 16-bit command, which is sent prior to the data for that register. the command is constructed as shown in table i. the command word begins with an r/w bit, which specifies the direction of data flow on the serial bus. the following four bits specify the page of memory this command is directed to, as shown in table ii. the next six bits specify the register address on that page of memory to which the data is directed. the last five bits are reserved for future use.
13 www.ti.com TSC2200 sbas191f addr register 00 x 01 y 02 z 1 03 z 2 04 kpdata 05 bat1 06 bat2 07 aux1 08 aux2 09 temp1 0a temp2 0b dac 0c reserved 0d reserved 0e reserved 0f reserved 10 zero 11 reserved 12 reserved 13 reserved 14 reserved 15 reserved 16 reserved 17 reserved 18 reserved 19 reserved 1a reserved 1b reserved 1c reserved 1d reserved 1e reserved 1f reserved page 0: data registers page 1: control registers addr register 00 adc 01 key 02 dacctl 03 ref 04 reset 05 config 06 reserved 07 reserved 08 reserved 09 reserved 0a reserved 0b reserved 0c reserved 0d reserved 0e reserved 0f reserved 10 kpmask 11 reserved 12 reserved 13 reserved 14 reserved 15 reserved 16 reserved 17 reserved 18 reserved 19 reserved 1a reserved 1b reserved 1c reserved 1d reserved 1e reserved 1f reserved table iii. TSC2200 memory map. figure 7. write and read operation of TSC2200 interface. write operation read operation command word command word data data data ss sclk mosi miso to read all the first page of memory, for example, the host processor must send the TSC2200 the command 8000 h this specifies a read operation beginning at page 0, address 0. the processor can then start clocking data out of the TSC2200. the TSC2200 will automatically increment its address pointer to the end of the page; if the host processor continues clocking data out past the end of a page, the TSC2200 will simply send back the value ffff h . likewise, writing to page 1 of memory would consist of the processor writing the command 0800 h , which would specify a write operation, with pg0 set to 1, and all the addr bits set to 0. this would result in the address pointer pointing at the first location in memory on page 1. see the TSC2200 memory map section for details of register locations. figure 7 shows an example of a complete data transaction between the host processor and the TSC2200. TSC2200 memory map the TSC2200 has several 16-bit registers that allow control of the device as well as provide a location for results from the TSC2200 to be stored until read by the host microprocessor. these registers are separated into two pages of memory in the TSC2200: a data page (page 0) and a control page (page 1). the memory map is shown in table iii.
14 www.ti.com TSC2200 sbas191f reset addr register value page (hex) name d15 d14 d13 d12 d11 d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 (hex) 0 00 x 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 0 01 y 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 002 z 1 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 003 z 2 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 0 04 kpdata k15 k14 k13 k12 k11 k10 k9 k8 k7 k6 k5 k4 k3 k2 k1 k0 0000 0 05 bat1 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 0 06 bat2 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 0 07 aux1 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 0 08 aux2 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 0 09 temp1 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 0 0a temp2 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 0000 0 0b dac x x x x x x x x d7 d6 d5 d4 d3 d2 d1 d0 007f 0 0c reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 0d reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 0e reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 0f reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 10 zero 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0000 0 11 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 12 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 13 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 14 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 15 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 16 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 17 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 18 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 19 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 1a reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 1b reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 1c reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 1d reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 1e reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 0 1f reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 00 adc psm sts ad3 ad2 ad1 ad0 rs1 rs0 av1 av0 cl1 cl0 pv2 pv1 pv0 x 4000 1 01 key stc scs db2 db1 db0 x x x x x x x x x x x 4000 1 02 dacctl dpd 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8000 1 03 ref x x x x x x x x x x x int dl1 dl0 pnd rfv 0002 1 04 reset 1 0 1 1 1 0 1 1 x x x x x x x x ffff 1 05 config 1 1 1 1 1 1 1 1 1 davb pr2 pr1 pr0 sn2 sn1 sn0 ffc0 1 06 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 07 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 08 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 09 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 0a reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 0b reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 0c reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 0d reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 0e reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 0f reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 10 kpmask m15 m14 m13 m12 m11 m10 m9 m8 m7 m6 m5 m4 m3 m2 m1 m0 0000 1 11 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 12 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 13 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 14 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 15 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 16 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 17 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 18 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 19 reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 1a reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 1b reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 1c reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 1d reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 1e reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff 1 1f reserved 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ffff note: x = don t care. table iv. register summary for TSC2200. TSC2200 control registers this section will describe each of the registers that were shown in the memory map of table iii. the registers are grouped according to the function they control. note that in the TSC2200, bits in control registers may refer to slightly different functions depending upon if you are reading the register or writing to it. a summary of all registers and bit locations is shown in table iv.
15 www.ti.com TSC2200 sbas191f table vii. sts bit operation. sts read/write value description read 0 converter is busy read 1 conversions are complete, data is available write 0 normal operation write 1 stop conversion and power down a/d3 a/d2 a/d1 a/d0 function 0 0 0 0 invalid. no registers will be updated. this is the default state after a reset. 0 0 0 1 touch screen scan function: x and y coordinates converted and the results returned to the x and y data registers. scan continues until either the pen is lifted or a stop bit is sent. 0 0 1 0 touch screen scan function: x, y, z 1 , and z 2 coordinates converted and the results returned to the x, y, z 1 , and z 2 data registers. scan continues until either the pen is lifted or a stop bit is sent. 0 0 1 1 touch screen scan function: x coordinate converted and the results returned to the x data register. 0 1 0 0 touch screen scan function: y coordinate converted and the results returned to the y data register. 0101 touch screen scan function: z 1 and z 2 coordinates converted and the results returned to the z 1 and z 2 data registers. 0 1 1 0 battery input 1 converted and the results returned to the bat1 data register. 0 1 1 1 battery input 2 converted and the results returned to the bat2 data register. 1 0 0 0 auxiliary input 1 converted and the results returned to the aux1 data register. 1 0 0 1 auxiliary input 2 converted and the results returned to the aux2 data register. 1 0 1 0 a temperature measurement is made and the results returned to the temperature measurement 1 data register. 1 0 1 1 port scan function: battery input 1, battery input 2, auxiliary input 1, and auxiliary input measurements are made and the results returned to the appropriate data registers. 1 1 0 0 a differential temperature measurement is made and the results returned to the temperature measurement 2 data register. 1 1 0 1 turn on x+, x drivers. 1 1 1 0 turn on y+, y drivers. 1 1 1 1 turn on y+, x drivers. table viii. a/d converter function select. psm read/write value description read 0 no screen touch detected read 1 screen touch detected write 0 conversions controlled by host write 1 conversions controlled by TSC2200 table v. psm bit operation. msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 psm sts ad3 ad2 ad1 ad0 rs1 rs0 av1 av0 cl1 cl0 pv2 pv1 pv0 x table vi. a/d converter control register. rs1 rs0 function 0 0 12-bit resolution. power up and reset default. 0 1 8-bit resolution 1 0 10-bit resolution 1 1 12-bit resolution table ix. a/d converter resolution control. TSC2200 a/d converter control register (page 1, address 00 h ) the a/d converter in the TSC2200 is shared between all the different functions. a control register determines which input is selected, as well as other options. the result of the conversion is placed in one of the result registers in page 0 of memory, depending upon the function selected. the a/d converter control register controls several aspects of the a/d converter. the register is formatted as shown in table vi. bit 15: psm pen status/control mode. reading this bit allows the host to determine if the screen is touched. writing to this bit determines the mode used to read coordinates: host controlled, or under control of the TSC2200 responding to a screen touch. when reading, the pensts bit indicates if the pen is down or not. when writing to this register, this bit determines if the TSC2200 controls the reading of coordi- nates, or if the coordinate conversions are host-controlled. the default state is host-controlled conversions (0). bit 14: sts a/d converter status. when reading, this bit indicates if the converter is busy, or if conversions are complete and data is available. writing a 0 to this bit will cause touch screen scans to continue until either the pen is lifted or the process is stopped. continuous scans or conver- sions can be stopped by writing a 1 to this bit. this will immediately halt a conversion (even if the pen is still down) and cause the a/d converter to power down. the default state is continuous conversions, but if this bit is read after a reset or power-up, it will read 1. bits [13:10]: ad3 C ad0 a/d converter function select. these bits control which input is to be converted, and what mode the converter is placed in. these bits are the same whether reading or writing. a complete listing of how these bits are used is shown in table viii. bits[9:8]: rs1, rs0 resolution control. the a/d converter resolution is specified with these bits. a description of these bits is shown in table ix. these bits are the same whether reading or writing.
16 www.ti.com TSC2200 sbas191f av1 av0 function 0 0 none 0 1 4 data averages 1 0 8 data averages 1 1 16 data averages table x. a/d conversion averaging control. cl1 cl0 function 0 0 8mhz internal clock rate 8-bit resolution only 0 1 4mhz internal clock rate 10-bit resolution only 1 0 2mhz internal clock rate 1 1 1mhz internal clock rate table xi. a/d converter clock control. msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 dpdxxxxxxxxx x xxxxx table xiii. d/a converter control register. msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 xxxxxxxxxx xintdl1dl0pdnrfv table xv. reference register. pv2 pv1 pv0 function 00 00 s stabilization time 0 0 1 100 s stabilization time 0 1 0 500 s stabilization time 0 1 1 1ms stabilization time 1 0 0 5ms stabilization time 1 0 1 10ms stabilization time 1 1 0 50ms stabilization time 1 1 1 100ms stabilization time table xii. panel voltage stabilization time control. dpd value description 0 d/a converter is powered and operational 1 d/a converter is powered down table xiv. dpd bit operation. int value description 0 external reference selected 1 internal reference selected table xvi. int bit operation. bits[7:6]: av1, av0 converter averaging control. these two bits allow you to specify the number of averages the converter will perform, as shown in table x. note that when averaging is used, the sts bit and the dav output will indicate that the converter is busy until all conversions necessary for the averaging are complete. the default state for these bits is 00, selecting no averaging. these bits are the same whether reading or writing. bits[5:4]: cl1, cl0 conversion clock control. these two bits specify the internal clock rate which the a/d converter uses when performing a single conversion, as shown in table xi. these bits are the same whether reading or writing. bits [3:1]: pv2 C pv0 panel voltage stabilization time control. these bits allow you to specify a delay time from the time a pen touch is detected to the time a conversion is started. this allows you to select the appropriate settling time for the touch panel used. table xii shows the settings of these bits. the default state is 000, indicating a 0ms stabili- zation time. these bits are the same whether reading or writing. bit 0: this bit is not used, and is a don t care when writing. it will always read as a zero. d/a converter control register (page 1, address 02 h ) the single bit in this register controls the power down control of the onboard d/a converter. this register is formatted as shown in table xiii. bit 15: dpd d/a converter power down. this bit controls whether the d/a converter is powered up and operational, or powered down. if the d/a converter is powered down, the a out pin will neither sink nor source current. reference register (page 1, address 03 h ) the TSC2200 has a register to control the operation of the internal reference. this register is formatted as shown in table xv. bit 4: int internal reference mode. if this bit is written to a 1, the TSC2200 will use its internal reference; if this bit is a zero, the part will assume an external reference is being supplied. the default state for this bit is to select an external reference (0). this bit is the same whether reading or writing. bits [3:2]: dl1, dl0 reference power-up delay. when the internal reference is powered up, a finite amount of time is required for the reference to settle. if measurements are made before the reference has settled, these measurements will be in error. these bits allow for a delay time for measure- ments to be made after the reference powers up, thereby assuring that the reference has settled. longer delays will be necessary depending upon the capacitance present at the ref pin (see typical characteristics). see table xvii for the delays. the default state for these bits is 00, selecting a 0 s delay. these bits are the same whether reading or writing.
17 www.ti.com TSC2200 sbas191f dl1 dl0 delay time 000 s 0 1 100 s 1 0 500 s 1 1 1000 s table xvii. reference power-up delay settings. pdn value description 0 internal reference is powered at all times 1 internal reference is powered down between conversions table xviii. pdn bit operation. int pdn reference behavior 0 0 external reference used, internal reference powered down 0 1 external reference used, interenal reference powered down 1 0 internal reference used, always powered up 1 1 internal reference used, will power up during conversions and then power down table xix. reference behavior possibilities. msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 x x x x x x x x x x pre2 pre1 pre0 sns2 sns1 sns0 table xxi. configuration control register. pre[2:0] pre2 pre1 pre0 time 00 020 s 00 184 s 0 1 0 276 s 0 1 1 340 s 1 0 0 1.044ms 1 0 1 1.108ms 1 1 0 1.300ms 1 1 1 1.364ms table xxiii. precharge times. sns[2:0] sns2 sns1 sns0 time 00 032 s 00 196 s 0 1 0 544 s 0 1 1 608 s 1 0 0 2.080ms 1 0 1 2.144ms 1 1 0 2.592ms 1 1 1 2.656ms table xxiv. sense times. rfv value description 0 1.25v reference voltage 1 2.5v reference voltage table xx. rfv bit operation. davb value description 0 data from a/d conversion is available. this will stay at 0 until the host has read all updated registers. 1 no new data is available. table xxii. pdn bit operation. bit 1: pdn reference power down. if a 1 is written to this bit, the internal reference will be powered down between conversions. if this bit is a zero, the internal reference will be powered at all times. the default state is to power down the internal reference, so this bit will be a 1. this bit is the same whether reading or writing. note that the pdn bit, in concert with the int bit, creates a few possibilities for reference behavior. these are detailed in table xix. bit 0: rfv reference voltage control. this bit selects the internal reference voltage, either 1.25v or 2.5v. the default value is 1.25v. this bit is the same whether reading or writing. TSC2200 configuration control register (page 1, address 05 h ) this control register controls the configuration of the precharge and sense times for the touch detect circuit. the register is formatted as shown in table xxi. bit 6: davb = data available. this bit mirrors the operation of the dav pin. when any conversion is complete, the dav pin and this bit will be a logic 0 (low). it will stay low until the register(s) updated by the conversion have been read. when all updated data has been read by the host, the dav pin and this bit will return to a logic 1 (high). bits [5:3]: pre[2:0] precharge time selection. these bits set the amount of time allowed for precharging any pin capacitance on the touch screen prior to sensing if a screen touch is happening. bits [2:0]: sns[2:0] sense time selection. these bits set the amount of time the TSC2200 will wait to sense a screen touch between coordinate axis conversions in penirq - controlled mode. TSC2200 keypad registers the keypad scanner hardware in the TSC2200 is controlled by two registers: the keypad control register and the keypad mask register. the keypad control register controls general keypad functions such as scanning and de-bouncing, whereas the keypad mask register allows certain keys to be masked from being detected at all.
18 www.ti.com TSC2200 sbas191f c1 c2 c3 c4 r1 k0 k1 k2 k3 r2 k4 k5 k6 k7 r3 k8 k9 k10 k11 r4 k12 k13 k14 k15 table xxx. keypad to key bit mapping. stc value description 0 no keys are pressed 1 keys pressed and de-bounced table xxvi. stc bit operation. scs read/write value description read 0 scanner or de-bouncer busy read 1 scans are complete, data is available write 0 normal operation write 1 stop scans table xxvii. scs bit operation. table xxviii. keypad de-bounce control. kbdb2 kbdb1 kbdb0 function 0 0 0 de-bounce: 2ms 0 0 1 de-bounce: 10ms 0 1 0 de-bounce: 20ms 0 1 1 de-bounce: 50ms 1 0 0 de-bounce: 60ms 1 0 1 de-bounce: 80ms 1 1 0 de-bounce: 100ms 1 1 1 de-bounce: 120ms msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 stc scs db2 db1 db0 x x x x x x x x x x x table xxv. keypad control register. msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 m15 m14 m13 m12 m11 m10 m9 m8 m7 m6 m5 m4 m3 m2 m1 m0 table xxix. keypad mask register. keypad control register (page 1, address 01 h ) the keypad control register is formatted as shown in table xxv. bit 15: stc = keyboard status. this bit reflects the opera- tion of the kbirq pin, with inverted logic. this bit will go high when a key is pressed and de-bounced. the default value for this bit is zero. bit 14: scs = keyboard scan status. when reading, this bit indicates if the scanner or de-bouncer is busy or if scans are complete and data is available. writing a zero to this bit will cause keyboard scans to continue until either the key is lifted or the process is stopped. continuous scans can be stopped by writing a 1 to this bit. this will immediately halt a conver- sion (even if a key is still down). the default value for this bit when read is 1. bits [13:11]: kbdb2-kbdb0 = keyboard de-bounce con- trol. these bits set the length of the de-bounce time for the keypad, as shown in table xxviii. the default setting is a 2ms de-bounce time (000). keypad mask register (page 1, address 10 h ) the keypad mask register is formatted as shown in table xxix. this is the same format as used in the keypad data register (page 0, address 04 h ). each bit in these registers represents one key on the keypad. in the mask register, if a bit is set (1), then that key will not be detected in keyboard scans. pressing that key on the keypad will also not cause a kbirq , if the bit is set. if the bit is cleared (0), the corresponding key will be detected. a 16-key keypad is mapped into the keypad mask (and keypad data) register, as shown in table xxx. the default value for this register is 0000 h , detecting all key presses. the result of a keypad scan will appear in the keypad data register. each bit will be set in this register, corresponding to the key(s) actually pressed. for example, if only key1 was pressed on a particular scan, the data in the register would read as 0002 h ; however, if keys 6, 8, and 13 were all pressed simultaneously on that scan, the data would read as 2140 h . multiple keys may be pressed simultaneously, and will generally be decoded correctly by the keypad scan circuitry. however, keys that land on three corners of a rectangle may cause a false reading of a key on the fourth corner of the rectangle. for example, if 0, 3, and 11 were pressed simultaneously, the key0, key3, and key11 bits will be set, but the key8 bit will also be set. thus, when considering using multiple-key combi- nations in an application, try to avoid combinations that put three keys on the corners of a rectangle. reset register (page 1, address 04 h ) the TSC2200 has a special register, the reset register, which allows a software reset of the device. writing the code bbxx h , as shown in table xxxi, to this register will cause the TSC2200 to reset all its registers to their default, power-up values. writing any other values to this register will do nothing. reading this register or any reserved register will result in reading back all 1 s, or ffff h .
19 www.ti.com TSC2200 sbas191f msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 1 0 11 1 011x x x x xxxx table xxxi. reset register. msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 k15 k14 k13 k12 k11 k10 k9 k8 k7 k6 k5 k4 k3 k2 k1 k0 table xxxiii. keypad data register. msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 x x x x x x x x d7 d6 d5 d4 d3 d2 d1 d0 table xxxiv. d/a converter register. table xxxii. result data format. msb lsb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 0 0 0 0 r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 r1 r0 msb lsb TSC2200 data registers the data registers of the TSC2200 hold data results from conversions or keypad scans, or the value of the d/a converter output current. all of these registers default to 0000 h upon reset, except the d/a converter register, which is set to 0080 h , representing the midscale output of the d/a converter. x, y, z 1 , z 2 , bat1, bat2, aux1, aux2, temp1, and temp2 registers the results of all a/d conversions are placed in the appro- priate data register (see tables iii and viii). the data format of the result word, r, of these registers is right-justified, as shown in table xxxii. keypad data register (page 0, address 04 h ) the keypad data register (page 0, address 04 h ) is format- ted as shown in table xxxiii. this is the same format as used in the keypad mask register (page 1, address 10 h ). each bit in these registers represents one key on the keypad. a 16-key keypad is mapped into the keypad data register, see table xxix. d/a converter data register (page 0, address 0b h ) the data to be written to the d/a converter is written into the d/a converter data register, which is formatted as shown in table xxxiv. zero register (page 0, address 10 h ) this is a reserved data register, but instead of reading all 1 s (ffff h ), when read will return all 0 s (0000 h ). operation touch screen measurements as noted previously in the discussion of the a/d converter, several operating modes can be used, which allow great flexibility for the host processor. these different modes will now be examined. conversion controlled by TSC2200 initiated at touch detect in this mode, the TSC2200 will detect when the touch panel is touched and cause the penirq line to go low. at the same time, the TSC2200 will start up its internal clock. it will then turn on the y-drivers, and after a programmed panel voltage stabilization time, power up the a/d converter and convert the y-coordinate. if averaging is selected, several conversions may take place; when data averaging is complete, the y- coordinate result will be stored in the y-register. if the screen is still touched at this time, the x-drivers will be enabled, and the process will repeat, but instead measuring the x-coordinate and storing the result in the x-register. if only x- and y-coordinates are to be measured, then the conversion process is complete. see figure 8 for a flowchart for this process. the time it takes to go through this process depends upon the selected resolution, internal conversion clock rate, averaging selected, panel voltage stabilization time, and precharge and sense times.
20 www.ti.com TSC2200 sbas191f figure 8. x- and y-coordinate touch screen scan, initiated by touch. the time needed to get a complete x/y-coordinate reading can be calculated by: (3) t 2.5 s + 2 t + t + t 2n n 1 f s coordinate pvs pre sns avg bits conv = ( ) +?+ ? ? ? ? ? ? 44 . where, t coordinate = time to complete x/y-coordinate reading t pvs = panel voltage stabilization time (see table xii) t pre = precharge time (see table xxii) t sns = sense time (see table xxiii) n avg = number of averages (see table x); for no averag- ing, n avg = 1 n bits = number of bits of resolution (see table ix) f conv = a/d converter clock frequency (see table xi) if the pressure of the touch is also to be measured, the process will continue in the same way, but measuring the z 1 and z 2 values, and placing them in the z 1 and z 2 registers (see figure 9). as before, this process time depends upon the settings described above. the time for a complete x, y, z 1 , and z 2 coordinate reading is given by: (4) t4.75s+3t+t+t4nn 1 f s coordinate pvs pre sns avg bits conv = ( ) +?+ ? ? ? ? ? ? 44 . screen touch issue interrupt penirq go to host-controlled conversion touch screen scan x and y penirq initiated done done no no yes yes yes no no yes is data averaging done is screen touched is panel voltage stabilization done turn on drivers: y+, y start clock store x-coordinates in x-register power down a/d converter power up a/d converter reset penirq and scan trigger turn off clock convert x-coordinates is psm = 1 no yes no is screen touched is data averaging done no yes yes is panel voltage stabilization done convert y-coordinates turn on drivers: x+, x power up a/d converter store y-coordinates in y-register reset penirq and scan trigger power down a/d converter turn off clock issue data available
21 www.ti.com TSC2200 sbas191f figure 9. x- y- and z-coordinate touch screen scan, initiated by touch. screen touch issue interrupt penirq go to host-controlled conversion touch screen scan x, y, and z penirq initiated done no no yes yes yes no no yes is data averaging done is screen touched is panel voltage stabilization done turn on drivers: y+, y start clock store x-coordinates in x-register power down a/d converter power up a/d converter reset penirq and scan trigger turn off clock done reset penirq and scan trigger turn off clock convert x-coordinates is psm = 1 no yes is panel voltage stabilization done convert z 1 -coordinates turn on drivers: y+, x power up a/d converter no yes is data averaging done done no yes no is screen touched is data averaging done yes convert z 2 -coordinates store z 2 -coordinates in z 2 -register reset penirq and scan trigger power down a/d converter turn off clock issue data available is screen touched no yes yes is panel voltage stabilization done convert y-coordinates turn on drivers: x+, x power up a/d converter no is data averaging done store y-coordinates in y-register power down a/d converter store z 1 -coordinates in z 1 -register
22 www.ti.com TSC2200 sbas191f figure 10. x- and y-coordinate touch screen scan, initiated by host. conversion controlled by TSC2200 initiated by host responding to penirq in this mode, the TSC2200 will detect when the touch panel is touched and cause the penirq line to go low. the host will recognize the interrupt request, and then write to the a/d converter control register to select one of the touch screen scan functions. the conversion process then proceeds as described above, and as outlined in figures 10 through 14. the main difference between this mode and the previous mode is that the host, not the TSC2200, decides when the touch screen scan begins. screen touch issue interrupt penirq go to host-controlled conversion touch screen scan x and y host initiated done done no no yes yes no no yes is data averaging done is screen touched is panel voltage stabilization done turn on drivers: y+, y start clock reset penirq store x-coordinates in x-register power down a/d converter power up a/d converter reset penirq and scan trigger turn off clock convert x-coordinates is psm = 1 yes no is screen touched no yes is panel voltage stabilization done convert y-coordinates turn on drivers: x+, x power up a/d converter no yes is data averaging done store y-coordinates in y-register power down a/d converter turn off clock issue data available done host writes a/d converter control register
23 www.ti.com TSC2200 sbas191f figure 11. x-, y-, and z-coordinate touch screen scan, initiated by host. screen touch issue interrupt penirq go to host-controlled conversion touch screen scan x, y, and z host initiated done done no no yes yes no no yes is data averaging done is screen touched is panel voltage stabilization done turn on drivers: y+, y start clock reset penirq store x-coordinates in x-register power down a/d converter power up a/d converter reset penirq and scan trigger turn off clock done reset penirq and scan trigger turn off clock convert x-coordinates is psm = 1 no yes no is screen touched is data averaging done no yes yes is panel voltage stabilization done convert z 2 -coordinates convert z 1 -coordinates turn on drivers: y+, x power up a/d converter no yes is data averaging done store z 2 -coordinates in z 2 -register store z 1 -coordinates in z 1 -register power down a/d converter turn off clock issue data available is screen touched no yes yes is panel voltage stabilization done convert y-coordinates turn on drivers: x+, x power up a/d converter no yes no is data averaging done store y-coordinates in y-register power down a/d converter done host writes a/d converter control register
24 www.ti.com TSC2200 sbas191f figure 12. x-coordinate reading initiated by host. screen touch issue interrupt penirq go to host-controlled conversion touch screen scan x-coordinate host initiated done no reset penirq no yes are drivers on start clock no yes is panel voltage stabilization done turn on drivers: y+, y start clock power up a/d converter is psm = 1 convert x-coordinates no yes is data averaging done store x-coordinates in x-register power down a/d converter turn off clock issue data available done host writes a/d converter control register
25 www.ti.com TSC2200 sbas191f figure 13. y-coordinate reading initiated by host. screen touch issue interrupt penirq go to host-controlled conversion touch screen scan y-coordinate host initiated done no reset penirq start clock no is panel voltage stabilization done turn on drivers: x+, x no is data averaging done no yes yes yes are drivers on convert y-coordinates start clock power up a/d converter is psm = 1 store y-coordinates in y-register power down a/d converter turn off clock issue data available done host writes a/d converter control register
26 www.ti.com TSC2200 sbas191f figure 14. z-coordinate reading initiated by host. screen touch host writes a/d converter control register issue interrupt penirq go to host-controlled conversion touch screen scan z-coordinate host initiated no no yes yes yes no no is data averaging done is panel voltage stabilization done turn on drivers: y+, x start clock reset penirq store z 1 -coordinates in z 1 -register power up a/d converter are drivers on start clock convert z 1 -coordinates yes no is data averaging done store z 2 -coordinates in z 2 -register power down a/d converter issue data available convert z 2 -coordinates is psm = 1 done done turn off clock
27 www.ti.com TSC2200 sbas191f figure 15. x-coordinate reading controlled by host. screen touch issue interrupt penirq go to host-controlled conversion host-controlled x-coordinate no start clock reset penirq no is panel voltage stabilization done turn on drivers: y+, y turn on drivers: y+, y no yes yes yes no is data averaging done convert x-coordinates start clock power up a/d converter is psm = 1 are drivers on done done host writes a/d converter control register host writes a/d converter- control register done power down a/d converter turn off clock issue data available store x-coordinates in x-register conversion controlled by the host in this mode, the TSC2200 will detect when the touch panel is touched and cause the penirq line to go low. the host will recognize the interrupt request. instead of starting a sequence in the TSC2200 which then reads each coordinate in turn, the host now must control all aspects of the conver- sion. generally, upon receiving the interrupt request, the host will turn on the y-drivers. after waiting for the settling time, the host will then address the TSC2200 again, this time requesting an x-coordinate conversion. the process is then repeated for y- and z-coordinates. the processes are outlined in figures 15 through 17. the time needed to convert any single coordinate under host control (not including the time needed to send the command over the spi bus) is given by: (5) t 2.125 s + t n n 1 f s coordinate pvs avg bits conv = + ? + ? ? ? ? ? ? 44 .
28 www.ti.com TSC2200 sbas191f figure 16. y-coordinate reading controlled by host. screen touch issue interrupt penirq go to host-controlled conversion host-controlled y-coordinate no start clock reset penirq no is panel voltage stabilization done turn on drivers: x+, x turn on drivers: x+, x no yes yes yes no is data averaging done convert y-coordinate start clock power up a/d converter is psm = 1 are drivers on done done host writes a/d converter control register host writes a/d converter control register done power down a/d converter turn off clock issue data available store y-coordinates in y-register
29 www.ti.com TSC2200 sbas191f figure 17. z-coordinate reading controlled by host. screen touch issue interrupt penirq go to host-controlled conversion host-controlled z-coordinate no reset penirq no is panel voltage stabilization done turn on drivers: y+, x turn on drivers: y+, x no yes yes yes is data averaging done no is data averaging done convert z 1 -coordinates start clock start clock power up a/d converter is psm = 1 done done host writes a/d converter control register reset penirq host writes a/d converter control register done convert z 2 -coordinates no yes is data averaging done store z 2 -coordinates in z 2 -register power down a/d converter turn off clock issue data available store z 1 -coordinates in z 1 -register
30 www.ti.com TSC2200 sbas191f figure 18. functional block diagram of temperature measurement mode. figure 19. single temperature measurement mode. figure 20. additional temperature measurement for differential temperature reading. operation temperature measurement in some applications, such as battery recharging, a measure- ment of ambient temperature is required. the temperature measurement technique used in the TSC2200 relies on the characteristics of a semiconductor junction operating at a fixed current level. the forward diode voltage (v be ) has a well-defined characteristic versus temperature. the ambient temperature can be predicted in applications by knowing the 25 c value of the v be voltage and then monitoring the delta of that voltage as the temperature changes. the TSC2200 offers two modes of temperature measurement. the first mode requires calibration at a known temperature, but only requires a single reading to predict the ambient tempera- ture. a diode, shown in figure 18, is used during this measure- ment cycle. this voltage is typically 600mv at +25 c with a 20 a current through it. the absolute value of this diode voltage can vary by a few millivolts; the temperature coefficient (tc) of this voltage is very consistent at 2.1mv/ c. during the final test of the end product, the diode voltage would be stored at a known room temperature, in system memory, for calibration purposes by the user. the result is an equivalent temperature measurement resolution of 0.3 c/lsb. this measurement of what is referred to as temperature 1 is illustrated in figure 19. the second mode does not require a test temperature calibration, but uses a two-measurement (differential) method to eliminate the need for absolute temperature calibration and for achieving 2 c/lsb accuracy. this mode requires a second conversion with a 91 times larger current. the voltage difference between the first (temp1) and second (temp2) conversion, using 91 times the bias current, will be represented by kt/q ln (n), where n is the current ratio = 91, k = boltzmann s constant (1.38054 10 -23 electrons volts/degrees kelvin), q = the electron charge (1.602189 10 -19 c), and t = the temperature in degrees kelvin. this method can provide much improved absolute temperature measurement, but less resolution of 2 c/lsb. the resultant equation for solving for k is: = ? ? k qv k ln(n) ? (6) where, ?= ( ) ? ( ) ( ) = ? = ?? ( ) ? vvi vi inmv k 2.573 v k/mv c 2.573 v mv 273 k 91 1 figure 20 shows the temperature 2 measurement. a/d converter mux x+ temperature select temp0 temp1 host writes a/d converter control register start clock temperature input 1 done yes no is data averaging done store temperature input 1 in temp1 register power down a/d converter power up a/d converter power up reference convert temperature input 1 issue data available power down reference turn off clock host writes a/d converter control register start clock temperature input 2 done yes no is data averaging done store temperature input 2 in temp2 register power down a/d converter power up a/d converter power up reference convert temperature input 2 issue data available power down reference turn off clock
31 www.ti.com TSC2200 sbas191f figure 21. battery measurement functional block diagram. figure 22. v bat1 measurement process. figure 23. v bat2 measurement process. operation battery measurement an added feature of the TSC2200 is the ability to monitor the battery voltage on the other side of a voltage regulator (dc/dc converter), as shown in figure 21. the battery voltage can vary from 0.5v to 6v while maintaining the voltage to the TSC2200 at 2.7v, 3.3v, etc. the input voltage (v bat1 or v bat2 ) is divided down by 4 so that a 6.0v battery voltage is represented as 1.5v to the a/d converter. this simplifies the multiplexer and control logic. in order to mini- mize the power consumption, the divider is only on during the sampling of the battery input. flowcharts that detail the process of making a battery input reading are shown in figures 22 and 23. the time needed to make temperature, auxiliary, or battery measurements is given by: (7) t 2.625 s + t n n 1 f s reading ref avg bits conv = + ? + ? ? ? ? ? ? 44 . where t ref is the reference delay time as given in table xvii. v dd v bat 7.5k ? 2.5k ? dc/dc converter battery 0.5v to 6.0v 0.125v to 1.5v 2.7v + host writes a/d converter control register start clock battery input 1 done yes no is data averaging done store battery input 1 in bat1 register power down a/d converter power up a/d converter power up reference convert battery input 1 issue data available power down reference turn off clock host writes a/d converter control register start clock battery input 2 done yes no is data averaging done store battery input 2 in bat2 register power down a/d converter power up a/d converter power up reference convert battery input 2 issue data available power down reference turn off clock
32 www.ti.com TSC2200 sbas191f figure 24. aux1 measurement process. figure 25. aux2 measurement process. figure 26. port scan mode. operation auxiliary measurement the two auxiliary voltage inputs can be measured in much the same way as the battery inputs, as shown in figures 24 and 25. applications might include external temperature sensing, ambient light monitoring for controlling the back- light, or sensing the current drawn from the battery. operation port scan if making measurements of all the analog inputs (except the touch screen) is desired on a periodic basis, the port scan mode can be used. this mode causes the TSC2200 to sample and convert both battery inputs and both auxiliary inputs. at the end of this cycle, the battery and auxiliary result registers will contain the latest values. thus, with one write to the TSC2200, the host can cause four different measure- ments to be made. the flowchart for this process is shown in figure 26. the time needed to make a complete port scan is given by: t 7.5 s + t + 4n n 1 f 4.4 s reading ref avg bits conv = + ? ? ? ? ? ? ? (8) host writes a/d converter control register start clock port scan done yes no is data averaging done yes no is data averaging done store battery input 1 in bat1 register power down a/d converter power up a/d converter power up reference convert battery input 1 store battery input 2 in bat2 register convert battery input 2 yes no is data averaging done yes no is data averaging done store auxiliary input 1 in aux1 register convert auxiliary input 1 store auxiliary input 2 in aux2 register convert auxiliary input 2 issue data available power down reference turn off clock host writes a/d converter control register start clock auxiliary input 2 done yes no is data averaging done store auxiliary input 2 in aux2 register power down a/d converter power up a/d converter power up reference convert auxiliary input 2 issue data available power down reference turn off clock host writes a/d converter control register start clock auxiliary input 1 done yes no is data averaging done store auxiliary input 1 in aux1 register power down a/d converter power up a/d converter power up reference convert auxiliary input 1 issue data available power down reference turn off clock
33 www.ti.com TSC2200 sbas191f figure 27. d/a converter configuration. figure 28. d/a converter output current range versus rrng resistor value. operation d/a converter the TSC2200 has an onboard 8-bit d/a converter, config- ured as shown in figure 27. this configuration yields a current sink (a out ) controlled by the value of a resistor connected between the arng pin and ground. the d/a converter has a control register that controls whether or not the converter is powered up. the 8-bit data is written to the d/a converter through the d/a converter data register. this circuit is designed for flexibility in the output voltage at the v bias point shown in figure 27 to accommodate the widely varying requirements for lcd contrast control bias. v+ can be a higher voltage than the supply voltage for the TSC2200. the only restriction is that the voltage on the a out pin can never go above the absolute maximum ratings for the device, and should stay above 1.5v for linear operation. the d/a converter has an output sink range that is limited to 1ma. this range can be adjusted by changing the value of rrng shown in figure 27. as this d/a converter is not designed to be a precision device, the actual output current range can vary as much as 20%. furthermore, the current output will change due to variations in temperature; the d/a converter has a temperature coefficient of approximately 2 a/ c. to set the full-scale current, rrng can be deter- mined from the graph shown in figure 28. for example, consider an lcd that has a contrast control voltage v bias that can range from 2v to 4v, which draws 400 a when used, and an available +5v supply. note that this is higher than the TSC2200 supply voltage, but it is within the absolute maximum ratings. the maximum v bias voltage is 4v, and this occurs when the d/a converter current is 0, so only the 400 a load current i load will be flowing from 5v to v bias . this means 1v will be dropped across r 1 , so r 1 = 1v/400 a = 2.5k ? . the minimum v bias is 2v, which occurs when the d/a converter current is at its full scale value, i max . in this case, 5v 2v = 3v will be dropped across r 1 , so the current through r 1 will be 3v/2.5k = 1.2ma. this current is i max + i load = i max + 400ua, so i max must be set to 800 a. looking at figure 28, this means that rrng should be around 1m ? . since the voltage at the a out pin should not go below 1.5v, this limits the voltage at the bottom of r 2 to be 1.5v minimum; this occurs when the d/a converter is providing its maximum current, i max . in this case, i max + i load flows through r 1 , and i max flows through r 2 . thus, r 2 i max + r 1 (i max + i load ) = 5v 1.5v = 3.5v (8) we already have found r 1 = 2.5k ? , i max = 800 a, i load = 400 a, so we can solve this for r 2 and find that it should be 625 ? . 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 10k 100k 1m 10m 100m i out (full-scale) (ma) arng resistor ( ? ) d/a converter v+ v bias a out arng rrng r 2 r 1 8 bits
34 www.ti.com TSC2200 sbas191f figure 29. d/a converter circuit when using v+ higher than v supply . figure 30. keypad scan initiated by keypress. in the previous example, when the d/a converter current is zero, the voltage on the a out pin will rise above the TSC2200 supply voltage. this is not a problem, however, since v+ was within the absolute maximum ratings of the TSC2200, so no special precautions are necessary. many lcd displays re- quire voltages much higher than the absolute maximum ratings of the TSC2200. in this case, the addition of an npn transistor, as shown in figure 29, will protect the a out pin from damage. operation keypad interface the TSC2200 contains a keypad interface that is suitable for use with matrix keypads up to 4-by-4 keys. a control register, the keypad control register, is used to set the scan rate for the keypad and de-bounce times. there is also a keypad mask register which allows certain keys to be masked from being read or causing the TSC2200 to detect a key press. the results of keyboard scans are placed in the keypad data register. when a key press is detected, the TSC2200 automatically scans the keypad and de-bounces the key press. it will then drive the kbirq low. all keys pressed at the time of the scan will then be reflected in the keypad data register. this mode is shown in figure 30. d/a converter v+ v supply v bias a out arng rrng r 2 r 1 8 bits keypad touch issue interrupt kbirq reset kbirq keypad scan kbirq initiated done start clock read kpdata register store keypad scan results in kpdata register scan and de-bounce keys turn off clock
35 www.ti.com TSC2200 sbas191f layout the following layout suggestions should provide optimum performance from the TSC2200. however, many portable applications have conflicting requirements concerning power, cost, size, and weight. in general, most portable devices have fairly clean power and grounds because most of the internal components are very low power. this situation would mean less bypassing for the converter s power and less concern regarding grounding. still, each situation is unique and the following suggestions should be reviewed carefully. for optimum performance, care should be taken with the physical layout of the TSC2200 circuitry. the basic sar architecture is sensitive to glitches or sudden changes on the power supply, reference, ground connections, and digital inputs that occur just prior to latching the output of the analog comparator. therefore, during any single conversion for an n-bit sar converter, there are n windows in which large external transient voltages can easily affect the conversion result. such glitches might originate from switching power supplies, nearby digital logic, and high power devices. the degree of error in the digital output depends on the reference voltage, layout, and the exact timing of the external event. the error can change if the external event changes in time with respect to the scl input. with this in mind, power to the TSC2200 should be clean and well bypassed. a 0.1 f ceramic bypass capacitor should be placed as close to the device as possible. a 1 f to 10 f capacitor may also be needed if the impedance of the connection between +v dd and the power supply is high. a bypass capacitor is generally not needed because the reference is buffered by an internal op amp. if an external reference voltage originates from an op amp, make sure that it can drive any bypass capacitor that is used without oscil- lation. the TSC2200 architecture offers no inherent rejection of noise or voltage variation in regards to using an external reference input. this is of particular concern when the reference input is tied to the power supply. any noise and ripple from the supply will appear directly in the digital results. while high-frequency noise can be filtered out, voltage variation due to line frequency (50hz or 60hz) can be difficult to remove. the gnd pin should be connected to a clean ground point. in many cases, this will be the analog ground. avoid connections that are too near the grounding point of a microcontroller or digital signal processor. if needed, run a ground trace directly from the converter to the power-supply entry or battery-connection point. the ideal layout will in- clude an analog ground plane dedicated to the converter and associated analog circuitry. in the specific case of use with a resistive touch screen, care should be taken with the connection between the converter and the touch screen. since resistive touch screens have fairly low resistance, the interconnection should be as short and robust as possible. loose connections can be a source of error when the contact resistance changes with flexing or vibrations. as indicated previously, noise can be a major source of error in touch screen applications (e.g., applications that require a back-lit lcd panel). this emi noise can be coupled through the lcd panel to the touch screen and cause flickering of the converted data. several things can be done to reduce this error, such as utilizing a touch screen with a bottom-side metal layer connected to ground. this will couple the major- ity of noise to ground. additionally, filtering capacitors, from y+, y , x+, and x to ground, can also help. note, however, that the use of these capacitors will increase screen settling time and require longer panel voltage stabilization times, as well as increased precharge and sense times for the penirq circuitry of the TSC2200.
package option addendum www.ti.com 10-jun-2014 addendum-page 1 packaging information orderable device status (1) package type package drawing pins package qty eco plan (2) lead/ball finish (6) msl peak temp (3) op temp (c) device marking (4/5) samples TSC2200ipw active tssop pw 28 50 green (rohs & no sb/br) cu nipdau level-1-260c-unlim -40 to 85 TSC2200i TSC2200ipwg4 active tssop pw 28 50 green (rohs & no sb/br) cu nipdau level-1-260c-unlim -40 to 85 TSC2200i TSC2200ipwr active tssop pw 28 2000 green (rohs & no sb/br) cu nipdau level-1-260c-unlim -40 to 85 TSC2200i TSC2200ipwrg4 active tssop pw 28 2000 green (rohs & no sb/br) cu nipdau level-1-260c-unlim -40 to 85 TSC2200i TSC2200irhb active vqfn rhb 32 73 green (rohs & no sb/br) cu nipdau level-2-260c-1 year -40 to 85 tsc 2200i TSC2200irhbr active vqfn rhb 32 3000 green (rohs & no sb/br) cu nipdau level-2-260c-1 year -40 to 85 tsc 2200i (1) the marketing status values are defined as follows: active: product device recommended for new designs. lifebuy: ti has announced that the device will be discontinued, and a lifetime-buy period is in effect. nrnd: not recommended for new designs. device is in production to support existing customers, but ti does not recommend using this part in a new design. preview: device has been announced but is not in production. samples may or may not be available. obsolete: ti has discontinued the production of the device. (2) eco plan - the planned eco-friendly classification: pb-free (rohs), pb-free (rohs exempt), or green (rohs & no sb/br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. tbd: the pb-free/green conversion plan has not been defined. pb-free (rohs): ti's terms "lead-free" or "pb-free" mean semiconductor products that are compatible with the current rohs requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. where designed to be soldered at high temperatures, ti pb-free products are suitable for use in specified lead-free processes. pb-free (rohs exempt): this component has a rohs exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. the component is otherwise considered pb-free (rohs compatible) as defined above. green (rohs & no sb/br): ti defines "green" to mean pb-free (rohs compatible), and free of bromine (br) and antimony (sb) based flame retardants (br or sb do not exceed 0.1% by weight in homogeneous material) (3) msl, peak temp. - the moisture sensitivity level rating according to the jedec industry standard classifications, and peak solder temperature. (4) there may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) multiple device markings will be inside parentheses. only one device marking contained in parentheses and separated by a "~" will appear on a device. if a line is indented then it is a continuation of the previous line and the two combined represent the entire device marking for that device.
package option addendum www.ti.com 10-jun-2014 addendum-page 2 (6) lead/ball finish - orderable devices may have multiple material finish options. finish options are separated by a vertical ruled line. lead/ball finish values may wrap to two lines if the finish value exceeds the maximum column width. important information and disclaimer: the information provided on this page represents ti's knowledge and belief as of the date that it is provided. ti bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. efforts are underway to better integrate information from third parties. ti has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. ti and ti suppliers consider certain information to be proprietary, and thus cas numbers and other limited information may not be available for release. in no event shall ti's liability arising out of such information exceed the total purchase price of the ti part(s) at issue in this document sold by ti to customer on an annual basis.
tape and reel information *all dimensions are nominal device package type package drawing pins spq reel diameter (mm) reel width w1 (mm) a0 (mm) b0 (mm) k0 (mm) p1 (mm) w (mm) pin1 quadrant TSC2200ipwr tssop pw 28 2000 330.0 16.4 6.9 10.2 1.8 12.0 16.0 q1 TSC2200irhbr vqfn rhb 32 3000 330.0 12.4 5.3 5.3 1.5 8.0 12.0 q2 package materials information www.ti.com 27-jul-2013 pack materials-page 1
*all dimensions are nominal device package type package drawing pins spq length (mm) width (mm) height (mm) TSC2200ipwr tssop pw 28 2000 367.0 367.0 38.0 TSC2200irhbr vqfn rhb 32 3000 338.1 338.1 20.6 package materials information www.ti.com 27-jul-2013 pack materials-page 2

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