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E2B0013-27-Y3
Semiconductor MSM6786
Semiconductor
This version: Nov. 1997 MSM6786 Previous version: Mar. 1996
1/3, 1/4 DUTY LCD DRIVER WITH 4-DOT COMMON DRIVER AND 29-DOT SEGMENT DRIVER
GENERAL DESCRIPTION
The MSM6786 is a dynamic display LCD driver and can be switched to 1/3 or 1/4 duty. It can dis-play up to 116 segments with 1/4 duty and up to 87 segments with 1/3 duty. It can also drive one LED directly. The built-in 56 key circuit allows input through a keyboard, and minimizes the number of wires between the front panel and CPU.
FEATURES
* Power suppy voltage : 5V10% * Operating temperature : -40 to +85C * 29-output segment driver 1/4 duty dynamic drive : Up to 116 segments can be displayed 1/3 duty dynamic drive : Up to 87 segments can be displayed * One LED can be driven directly (IO=-15mA max) * Built-in 56 key scan circuit allows reading of the operation status of up to 30 switches. * Interface with CPU is implemented by LOAD, DATA I/O and CLOCK in serial method. * Built-in RC oscillator for LCD AC drive * Built-in voltage dividing resistor for bias voltage generation * Package: 56-pin plastic QFP (QFP56-P-910-0.65-2K) (Product name : MSM6786GS-2K)
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Semiconductor
MSM6786
BLOCK DIAGRAM
LED
SEG1
SEG29
LED DRV.
29-DOT SEG. DRV.
3/4SEL
TIMING GEN. 29-BIT DATA SELECTOR COM1 COM. DRV. COM2 COM3 COM4
OSC
OSC
VDD
(DATA LATCH1) 30-BIT LATCH
(DATA LATCH2) 29-BIT LATCH
(DATA LATCH3) 29-BIT LATCH
(DATA LATCH4) 29-BIT LATCH
RESET MODE SELECTOR
VDD VSS
TEST LOAD DATA I/O LOGIC CLOCK VDD 56 KEY SCANNER CONTROL C5 C4 C3 C2 C1 C0 36(30+6)-BIT SHIFT REGISTER INT
C0 C1 C2 C3 C4 C5 R0 R1 R2 R3 R4
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PIN CONFIGURATION (TOP VIEW)
SEG1 SEG2 SEG3 SEG4 SEG5 SEG6 SEG7 SEG8 SEG9 SEG10 SEG11 SEG12 SEG13 SEG14
1 2 3 4 5 6 7 8 9 10 11 12 13 14
56 55 54 53 52 51 50 49 48 47 46 45 44 43
42 41 40 39 38 37 36 35 34 33 32 31 30 29
COM1 COM2 COM3 COM4 TEST VSS OSC VDD 3/4SEL LED RESET INT DATAI/O CLOCK
LOAD R4 R3 R2 R1 R0 C5 C4 C3 C2 C1 C0 SEG29 SEG28
SEG15 SEG16 SEG17 SEG18 SEG19 SEG20 VDD SEG21 SEG22 SEG23 SEG24 SEG25 SEG26 SEG27
15 16 17 18 19 20 21 22 23 24 25 26 27 28
56-Pin Plastic QFP
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Semiconductor
MSM6786
ABSOLUTE MAXIMUM RATINGS
Parameter Power Supply Voltage Input Voltage Output Current Storage Temperature Symbol VDD VI IO TSTG Condition Ta=+25C Ta=+25C Ta=+25C --
*1
Rating -0.3 to +6.5 -0.3 to VDD+0.3 -20 -55 to +150
Unit V V mA C
*1 Applied to LED output
RECOMMENDED OPERATING CONDITIONS
Parameter Power Supply Voltage Operating Temperature Symbol VDD Top Condition VSS=OV -- Range 4.5 to 5.5 -40 to +85 Unit V C
Specifications of External Parts (oscillation circuit)
Parameter Oscillation Resistor (Resistance) Oscillation Capacitor (Capacitance) Symbol RO CO Condition -- -- Min. 20 0.01 Max. 82 0.047 Unit kW mF
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ELECTRICAL CHARACTERISTICS
DC Characteristics
(VDD=5V10%, Ta=-40 to +85C) Parameter "H" Input Voltage "L" Input Voltage "H" Input Voltage "L" Input Voltage "H" Input Current "L" Input Current "H" Input Current "L" Input Current "L" Input Current "L" Input Current Segment Output Voltage Symbol VIH1 VIL1 VIH2 VIL2 IIH1 IIL1 IIH2 IIL2 IIL3 IIL4 VOS0 VOS1 VOS2 VOS3 VOC0 Common Output Voltage "H" Output Voltage "L" Output Voltage "H" Output Voltage "L" Output Voltage "H" Output Voltage "L" Output Voltage Supply Current VOC1 VOC2 VOC3 VOH1 VOL1 VOH2 VOL2 VOH3 VOL3 IDD VI=0V VI=VDD VI=0V VDD=5.0V, VI=0V VDD=5.0V, VI=0V IO=-10mA IO=10mA IO=10mA IO=10mA IO=-10mA IO=10mA IO=10mA IO=10mA IO=-15mA IO=0.1mA IO=-0.4mA IO=0.4mA IO=-50mA IO=1.0mA *2 Condition -- -- -- -- VI=VDD Min. 0.8VDD 0 0.7VDD 0 -- -- -- -- -0.07 -0.009 VDD-0.8 2/3VDD-0.8 1/3VDD-0.8 -- VDD-0.77 2/3VDD-0.77 1/3VDD-0.77 -- VDD-1.5 -- VDD-0.4 -- 2.5 -- -- Max. VDD 0.2VDD VDD 0.3VDD 1 -1 10 -10 -0.36 -0.045 -- 2/3VDD+0.8 1/3VDD+0.8 0.8 -- 2/3VDD+0.77 1/3VDD+0.77 0.77 -- 0.4 -- 0.4 -- 0.4 0.4 Unit Applied Pin V V V V mA CLOCK, LOAD 3/4SEL mA mA mA mA mA V V V V V V V V V V V V V V mA VDD DATA I/O INT R0-R4 LED COM1-COM4 C0-C5 RESET SEG1-SEG29 DATA I/O C0-C5 *1
*1 CLOCK, LOAD, DATA I/O, RESET and 3/4SEL *2 CO = 0.022 mF, RO = 33 kW, no load
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Semiconductor Switching Characteristics
MSM6786
(VDD=5V10%, Ta=-40 to +85C) Parameter Clock Frequency Clock Pulse Width Rise/Fall Time Data Setup Time Data Hold Time Load Pulse Width ClockAELoad Time LoadAEClock Time Output Delay Time 1 Output Delay Time 2 Symbol fCP tWCP tr,tf tDSU tDHD tWLD tCL tLC tPD1 tPD2 Condition -- -- -- -- -- -- -- -- CL=50pF -- Min. -- 200 -- 100 100 200 100 200 -- -- Max. 2.0 -- 50 -- -- -- -- -- 300 300 Unit MHz ns ns ns ns ns ns ns ns ns
tWCP tr CLOCK 0.8VDD
tWCP tf 0.2VDD 1/fCP 0.8VDD 0.2VDD
tDSU tDHD
DATA I/O
0.8VDD 0.2VDD (During input mode) tWLD
tCL LOAD
0.8VDD
tLC 0.2VDD tPD1 tPD1 0.8VDD 0.2VDD
DATA I/O (When changing from input mode to output mode) HiZ tPD2 DATA I/O (When changing from output mode to input mode)
HiZ (The charging and discharging time during high impedance depends on trace resistance and stray capacitance.)
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FUNCTIONAL DESCRIPTION Pin Functional Description
OSC (Pin 50) This is an input/output pin for the oscillator to generate LCD AC lighting and keyscan pulses. Connect an external capacitor and resistor as shown below to form an RC oscillation circuit. The relationship between frame frequency fFRM, keyscan period TSCN and oscillation frequency fOSC is: fFRM = fOSC/24, TSCN = 20/fOSC
VDD RO OSC CO
DATA I/O (Pin 44) This is a serial data input/output pin. The pin is in output state from the first shift clock rise after key data output command writing, to the load pulse rise, and in input state otherwise. (The pin is in input state during reset.) The relationship between the data levels of this pin and the operations is shown below.
Level "H" "L" Display ON OFF Key Status ON (close) OFF (open)
CLOCK (Pin 43) This is an input pin for the shift clock. DATA I/O pin data is either input or output in synchroniza-tion with each rising clock edge. LOAD (Pin 42) This is a load pulse input pin used to transfer serial input data to a latch for display, to write commands, or to release the DATA I/O pin in output state.
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R0 - R4 (Pin 37-Pin 41) These are key switch scan pulse output pins. During the scan operating, "L" level is output in sequence. All pluses go to "L" level when scanning stops. C0 - C5 (Pin 31-Pin 36) These are input pins that detect the key status. These pins have pull-up resistors. Key matrices are formed with pins R0 - R4.
C0
C1
C2
C3
C4
C5
R0 R1 R2 R3 R4
INT (Pin 45) This is the keyscan end signal output pin. This pin becomes "H" when one scan cycle is completed, and returns to "L" by a load pulse after data output or when the "Scan Stop" command is written. (The pin is in "L" status during reset.) If this pin is not used, leave it unconnected.
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RESET (Pin 46) This is a reset signal input pin that intializes the IC, and is activated at "L" level. This pin has an internal pull-up resistor. The power ON reset usually operates by externally connecting a capacitor.
VDD
CRST
RESET
SEG1 - SEG29 (Pin 1-Pin 20, Pin 22-Pin 30) These are the output pins for LCD, and are connected to the segment pins of the LCD panel. See the section on data configuration for the relationship between SEG output and input data. COM1 - COM4 (Pin 56-Pin53) These are output pins for the LCD, and are connected to common pins of the LCD panel. When 1/3 duty is selected, COM4 pin should be left unconnected. See the section on data configuration of common output and input data. LED (Pin 47) This is an output pin for the LED drive. The LED and current limiting resistor are externally connected.
LED
3/4SEL (Pin 48) This is a duty select input pin. When "H" level is input, 1/3 duty is selected and when "L" level is input, 1/4 duty is selected. TEST (Pin 52) This is an input pin for IC testing. This pin should be connected to VSS. VDD, VSS (Pin 21, 49, 51) These are power voltage supply and ground pins.
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MSM6786
Operating Description
Display data input As shown in the section on data configuration, the data for display consists of data fields that correspond to segment ON/OFF and command fields which indicate display data input. Set the bits C0 to C1 of the command field to "0" or "1" according to the common to which the display data corresponds. To the other four bits, set the display data input commands. LED display data corresponds to common 1. Data input to the DATA I/O pin is saved in a shift register at the rising edge of the CLOCK pulse, and is transferred to a data latch for display while the LOAD pulse is at "H" level, and is then output through a segment driver.
CLOCK DATAI/O
LOAD
Display Output
Key data output
The state of a key switch is indicated by ON = 1, OFF = 0, and is read as 30 bits serial data. (For information on the sequence, see the section on data configuration.) To output data, the output command must be written, which causes the data to be output in synchronization with the rising edge of the CLOCK pulse. By inputting a LOAD pulse after that, the DATA I/O pin returns to the input state, and the next data or command can be input. (If a LOAD pulse is applied earlier than the 30th data, the key data is output only by the number of the CLOCK pulse. If CLOCK pulses more than 30 data bits are applied, 30 data bits of key data are circulated.)

D1 D2 D3 D4 D28 D29 D30 C0 C1 C2 C3 C4 C5 Old Data New Data
CLOCK DATAI/O C3 C4 C5 O1 O2 O3 O29 O30
LOAD Output Command Write Key Data Read Next Command Input
Note1 : The last key data must be read before the LOAD pulse rises. Note2 : Upon swiching from output mode to input mode, the state of the DATA I/O pin is unstable for the duration of 300 ns after the rising of LOAD pulse. For this reason, never input data to the DATA I/O pin during this period. 10/16
Semiconductor Keyscan
MSM6786
Keyscan starts when the key state is changed or when the "Keyscan Start" command is written. Scan continues until the "Keyscan Stop" command is written. (When powered on, the powerON reset sets at scan stop state.) When 1 keyscan cycle ends, the INT signal becomes "H", so this signal can be used as an interrupt flag. The INT signal is reset when either the LOAD pulse is input after key data is output, when the "Keyscan Stop" command is set, or when a reset signal is applied.
TSCN R0
R1
R2
R3
R4
INT
Scan Start Command Write Data Read or Key Status Changed
Data Read
Data Read
Scan Stop Command Write
Notes : 1. A recognition error may occur if 3 or more key switches are pressed at the same time. (A switch that was not pressed is recognized as being pressed.) To properly recognize 3 or more key switches as being pressed at the same time, serially insert diodes at each switch. In order not to recognize 3 or more key switches as being pressed at the same time, a possible approach is to program the software so that the read data will be ignored when there are 3 or more ones in the data. The device recognizes simultaneous pressing of 2 key switches. However, take Note 2 into consideration. 2. A change of key state is detected as a change in column input (C0 - C5). Therefore even if multiple switches connected to the same column are pressed at the same time, nothing will be detected as a change.
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Semiconductor Display on, Display off
MSM6786
In power ON reset state, display will go out. To turn the display on, write the display ON command. The display and LED can go out by writing the display OFF command, irrespective of display data. Display ON command releases the display OFF state. By writing this command, display will return to original state.
CLOCK DATAI/O D1 D2
C4 C5
LOAD Display On/Off
RESET Display Data Input
Command List
Command Name C5 C4 C3 C2 C1 C0 F1 0 0 1 0 0 1 F2 F3 0 0 1 1 0 1 0 0 1 0 1
0 1

C2 C3 C4 C5 C2 C3 C4 C5 Display On Command Write Display Off Command Write
Operation
Display Data Input (Corresponding to Common 1) Display Data Input (Corresponding to Common 2) Display Data Input (Corresponding to Common 3) Display Data Input (Corresponding to Common 4) Key Data Output Display Data Input (1) + Key Data Output Display Data Input (2) + Key Data Output Display Data Input (3) + Key Data Output Display Data Input (4) + Key Data Output Display Off Display On Key Scan Stop + Key Data Output Key Scan Stop Key Scan Start + Key Data Output
0 1 0 1
F4 F5 F6 F7 F8
1 1 1 1 1
0 0 1 0 1
1 1 0 0 1
0 1

: Don't care
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Semiconductor Data Configuration (Input data)
MSM6786
First Bit Corresponds to SEG29 Corresponds to SEG1
C5
C4
C3
C2
C1
C0
D30
D29
D28
D3
D2
D1
Command
LCD Display Data LED Display Data
Notes : 1. LED data corresponds to common 1 side (C0, C1 = 0). 2. D1 bit is unnecessary when LED output is not used. 3. Data output commands F2, F6 - F8 become effective if at least 3 bits (C3 - C5) are input. (D1 - D30 and C0 - C2 bits are not necessary.) Command F4 and command F5 become effective if at least 4 bits (C2 - C5) are input. (D1 - D30, C0 and C1 bits are not necessary.) 4 . If dummy bits are necessary, add them before first bit.
(Output data)
Last Bit 30 R4 R3 R2 R1 R0 1 First Bit
C5 C4 C3 C2 C1 C0 C5 C4 C3 C2 C1 C0 C5 C4 C3 C2 C1 C0 C5 C4 C3 C2 C1 C0 C5 C4 C3 C2 C1 C0
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MSM6786
APPLICATION CIRCUIT
COM1 1/4 duty LCD Panel COM2 COM3 COM4 SEG1 SEG29
SEG1
SEG29
COM1 COM2 COM3
LOAD DATAI/O
COM4
CPU
CLOCK INT 3/4SEL RESET
MSM6786
LED VDD OSC VSS TEST +5V
C0 C1 C2 C3 C4 C5
R0 R1 R2 R3 R4
56 Key Matrix
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MSM6786
REFERENCE DATA
fFRM vs. RO, CO 1000
Ta = 25 [C] VDD= 5.0 [V]
Frame Frequency fFRM [Hz]
400 300 200 100 70 50 30 20 CO = 0.033F 10 CO = 0.01F CO = 0.022F
1 20 40 60 80 91 100
Resistance RO [kW] Frame frequency Characteristics The scanning period TSCN is defined by the following equation: TSCN = = 5 [ms] 6fFRM 20 fOSC [ms]
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MSM6786
PACKAGE DIMENSIONS
(Unit : mm)
QFP56-P-910-0.65-2K
Mirror finish
Package material Lead frame material Pin treatment Solder plate thickness Package weight (g)
Epoxy resin 42 alloy Solder plating 5 mm or more 0.43 TYP.
Notes for Mounting the Surface Mount Type Package The SOP, QFP, TSOP, SOJ, QFJ (PLCC), SHP and BGA are surface mount type packages, which are very susceptible to heat in reflow mounting and humidity absorbed in storage. Therefore, before you perform reflow mounting, contact Oki's responsible sales person for the product name, package name, pin number, package code and desired mounting conditions (reflow method, temperature and times).
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