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ace 5372 low power real - tim e clock (rtc) ver 1. 3 1 d escription the ace 5372 is a cmos type real - time clock, which is connected to the cpu via two wires and capable of serial transmission of clock to the cpu. the ace 5372 can generate various periodic interrupt clock pulses lasting for long period (one month ), and alarm interrupt can be made by two incorporated systems. since an oscillation circuit is driven at a constant voltage, it undergoes fluctuations of few voltage and consequently offers low current consumption (typ. 400na @ 5v) it also provides an os cillator halt sensing function applicable for data validation at power - on and other occasions. the product also incorporates a time trimming circuit that adjusts the clock with higher precision by adjusting any errors in crystal oscillator frequencies base d on signals from the cpu. the crystal oscillator may be selected from 32khz or 32.768khz types. features ? lowest supply current: 400na t yp .@5v ? connected to the cpu via only 2 - w ires (max. 100khz) ? a clock counter (counting hours. m inutes. and seconds) and a calendar counter (counting leap years, years, months, days, and days of the week) in bcd codes. ? two system output of alarm functions ? oscillation halt sensing to judge internal data validity ? clock output of 32.768khz (32khz) (output controllable via a re gister) ? second digit adjustment by 30 seconds ? automatic leap year recognition up to the year 2099 ? 12 - hour or 24 - hour time display selectable ? high precision time trimming circuit ? oscillator of 32.768khz or 32khz may be used ? cmos logic packaging type so p - 8 tssop - 8 sop - 8 / tssop - 8 description function value in/out 1 intrb interrupt output b 0~12v o ut 2 scl serial clock line 0~5.5v i n 3 sda serial data line 0~5.5v i n /o ut 4 gnd ground power 0v p ower 5 intra interrupt output a 0~12v o ut 6 oscout oscillator circuit output 0~1.5v o ut 7 oscin oscillator circuit input 0~1.5v in 8 vdd supply voltage 1.8~5.5v p ower 1 8 2 7 3 6 4 5 1 8 2 7 3 6 4 5
ace 5372 low power real - time clock (rtc) ver 1. 3 2 ordering information ace 5 372 xx + h block d iagram vdd and gnd a ce5372 the vdd pin is connected to the positive power supply and gnd to the ground . to prevent the possibility of noise, when rapidly changing signal took place on ace5372 pin, we have to place a capacitance beside the ace5372. one possibility is to place a bypass capacitance as close as to the ace5372. the capacitance capacity of c2 could be determined per user s demand, which provides large current passing ability between the pin and the ground. fm : sop - 8 tm : tssop - 8 pb - free ace5372 halogen - free
ace 5372 low power real - time clock (rtc) ver 1. 3 3 bypass capacitance oscin and oscout these pins configure an oscillator circuit by connecting a crystal oscillator between the oscin - oscout pins. the diagram beside shows the connection method of such crystal oscillator circuit. its recommended to choo se the right crystal oscillator parameter referring to the suppliers suggestion, since it does determine the start - up reliability and oscillation stability provided by external devices. the influence of the distributing capacitance should be considered wh en choosing capacitance capacity in an oscillator circuit. to minimize output distortion, both crystal oscillator and capacitance should be installed as close to ace 5372 pin as possible. ace5372 crystal oscillator connection with external capacitance scl and sda scl and sda are serial clock line and serial data line, relatively. scl is used to input shift clock pulses to syn chronize data input/output to and from the sda pin with this clock. sda inputs and outputs written or read data in synchronization with shift clock pulses from the scl pin. depend on different level of current, separate pull - up resistance can be added to s cl and sda on exterior circuit board. intra and intrb intra and intrb are two interrupt output ports and are both open drain outputs. when using ace 5372 a pull - up resistance must be connected with pins of intra and intrb. intra could output periodic interr upt pulses and alarm interrupt (alarm - a, alarm - b); intrb could output 32.768khz clock pulses (when 32.768khz crystal is used), periodic interrupt pulses, alarm interrupt (alarm - b). when power is activated from 0v, it could output 32.768khz clock pulses (wh en 32.768khz crystal is used). functional descriptions allocation of i nternal addresses internal address contents function 0h second counter counting and storing seconds in bcd codes 1h minute counter counting and storing minutes in bcd codes 2h hour c ounter counting and storing hours in bcd codes 3h day of the week counter counting and storing days of the week in bcd codes 4h day counter counting and storing days in bcd codes 5h month counter counting and storing months in bcd codes 6h year counter counting and storing years in bcd codes
ace 5372 low power real - time clock (rtc) ver 1. 3 4 7h time trimming register storing adjusting parameter and external select control of crystal oscillator 8h alarm _ a (minute register) storing minutes in timer a 9h alarm_a (hour register) storing hours in timer a ah alarm_a (day of the week register) storing days of the week in timer a bh alarm_b (minute register) storing minutes in timer b ch alarm_b (hour register) storing hours in timer b dh alarm_b (day of the week register) storing days of the week in time r b eh control register 1 storing ring enable, interrupt output port select, and periodic interrupt cycle select information fh control register 2 storing time display select, interrupt and alarm signal, oscillator halt sensing information calendar cou nter the ace 5372 can exchange from year to second (lower two bits) with cpu. when the lower two bits of the year could be divided by 4, that year is leap year. it could automatically recognize the year between 2000 and 2099 and these data are stored separa tely in registers from 0h to 6h . control unit the control unit is a substantial part of the ace5372, under which all functionalities of the whole circuit is realized. the time display select, interrupt / alarm select and signal, output port select, as well as oscillation halt sensing informatio n are all sent out by the control circuit. high precision time trimming function the ace 5372 has an internal oscillation circuit capacitance cgnd and cvdd so that an oscillation circuit may be configured simply by ext erna lly connecting a crystal. the ace 5372 incorporates a time trimming circuit (at internal address 7h) that adjusts gain or loss of the clock from the cpu up to approx.189ppm(194ppm when 32.000khz crystal is used) by approximately 3ppm steps to correct discrepancy in oscillation frequency. * clock display is possible at much higher precision than conventional real - time clock while using a crystal with broader fluctuation in precision. * even seasonal frequency fluctuation may be corrected by adjusting seasonal clock error. for those systems that have temperature detection precision of clock, function may be increased by correcting clock error according to temperature fluctuations.
ace 5372 low power real - time clock (rtc) ver 1. 3 5 alarm function and periodic interrupt alarm function : the ace 5372 has an alarm function that outputs an interrupt signal from ? intra or ? intrb output pins to the cpu when the day of the week, hour or minute corresponds to the setting. these two systems of alarms (alarm - a, alarm - b), each may output interrupt signal sepa rately at a specific time. th e alarm may be selectable between on and off for each day of the week, thus allowing outputting alarm everyday or on a specific day of the week. the alarm - a is output from the ? intra pin while the alarm - b is output from either t he ? intra or the ? intrb pins. polling is possible separately for each alarm function. periodic interrupt: the ace 5372 can output periodic interrupt pulses in addition to alarm function from the ? intra and ? intrb pins. this frequency may be selected from 2hz, 1hz, 1/60hz, 1/3600hz and monthly by controlling register (at lower 3 bits of internal address eh) output selectively. output waveform for periodic interrupt may be selected from regular pulse waveform (2hz and 1hz) and waveforms (every second, every minu te, every hour and every month) that are appropriate for cpu leve l oscillation halt sensing the oscillation halt sending function uses a register (xstp bit at internal address fh) t o store oscillation halt information. this function may be used to determin e if the ace 5372 supply power has been booted from 0v and if it has been backed up. this function is useful for determining if clock data is valid or invalid. clock output the ace 5372 may output oscillation frequency from intrb pin. this clock output is s et for output by default, which is set to on or off by setting the register (internal address fh bit clen). it can also choose different crystal oscillator (32.768khz or 32.000khz) by setting the register (internal address 7h at bit xsl), and output clock pulses with two different frequencies. registers 1. clock counter ( at internal address 0 - 2h ) * time digit display ( in bcd code ) second digits: range from 00 to 59 and carried to minute digits when incremented from 59 to 00. minute digits: range from 00 to 59 and carried to hour digits when incremented from 59 to 00. hour digits: see descriptions on the ? 12/24 bit (section 7). carried to day and day - of - the week digits when incremented from 11 p.m. to 12 a.m. or 23 to 00. any registered imaginary time should be replaced with correct time as carrying to such registered imaginary time digits from lower - order ones cause the clock counter malfunction. second digit register ( at internal address 0h) d7 d6 d5 d4 d3 d2 d1 d0 operation - s40 s20 s10 s8 s4 s2 s1 write 0 s40 s20 s10 s8 s4 s2 s1 read 0 undefined undefined undefined undefined undefined undefined undefined default
ace 5372 low power real - time clock (rtc) ver 1. 3 6 minute digit register ( at internal address 1h ) d7 d6 d5 d4 d3 d2 d1 d0 operation - m40 m20 m10 m8 m4 m2 m1 write 0 m40 m20 m10 m8 m4 m2 m1 read 0 undefined undefined undefined undefined undefined undefined undefined default hour digit register ( at internal address 2h) d7 d6 d5 d4 d3 d2 d1 d0 operation - - h20 or p/ ? ? * default means read value when xstp bit is set to i by starting up from 0v, or supply voltage drop etc. 2. day - of - the - week counter ( at internal address 3h) *day - of - the - w eek digits are incremented by 1 when carried to 1 - day digits. * day - of - the - week digits display (incremented in septimal notation): (w4,w2,w1) = (0,0,0)(0,0,1)(1,1,0)(0,0,0) * the relation between days of the week and day - of - the - week digits is defined as: sunday=(0,0,0); monday=(0,0,1); ; saturday=(1,1,0) (w4, w2, w1) should not be set to (1,1,1). d7 d6 d5 d4 d3 d2 d1 d0 opera tion - - - - - w4 w2 w1 write 0 0 0 0 0 w4 w2 w1 read 0 0 0 0 0 undefined undefined undefined default *the default means read value when xstp bit is set to 1 by starting up from 0v, or supply voltage drop, etc. 3. calendar counter ( at internal addr ess4 - 6h ) * the automatic calendar function provides the following calendar digit displays in bcd code and could recognize the leap year. day digits: range from 1 to 31 (for january, march, may, july, august, october, and december). range from 1 to 3 0 (for april, june, september, and november) range from 1 to 29 (for february in leap years) range from 1 to 28 (for february in ordinary years) month digits: range from 1 to 12 and carried to year digits when cycled to 1. carried to year digits when cycled from 12 to 1. year digits: range from 00 to 99 and 00,04,08, .,92, and 96 are counted as leap years. any registered imaginary time should be replaced with correct time as carrying to such registered imaginary time digits from lower - order ones cause the clock counter malfunction.
ace 5372 low power real - time clock (rtc) ver 1. 3 7 day digit register ( at internal address 4h ) d7 d6 d5 d4 d3 d2 d1 d0 operation - - d20 d10 d8 d4 d2 d1 write 0 0 d20 d10 d8 d4 d2 d1 read 0 0 undefined undefined undefined undefined undefined u ndefined default *default means read value when xstp bit is set to 1 by starting up from 0v, or supply voltage drop, etc. mouth digit register ( at internal address 5h ) d7 d6 d5 d4 d3 d2 d1 d0 operation - - - mo10 mo8 mo4 mo2 mo1 write 0 0 0 mo10 mo 8 mo4 mo4 mo1 read 0 0 0 undefined undefined undefined undefined undefined default *default means read value when xstp bit is set to 1 by starting up from 0v, or supply voltage drop, etc. year digit register ( at internal address 6h ) d7 d6 d5 d4 d3 d 2 d1 d0 operation y80 y40 y20 y10 y8 y4 y2 y1 write y80 y40 y20 y10 y8 y4 y2 y1 read undefined undefined undefined undefined undefined undefined undefined undefined default *default means read value when xstp bit is set to 1 by starting up from 0v, o r supply voltage drop, etc. 4. time trimming register ( at internal address 7h ) d7 d6 d5 d4 d3 d2 d1 d0 operation xsl_ f6 f5 f4 f3 f2 f1 f0 write xsl_ f6 f5 f4 f3 f2 f1 f0 read 0 0 0 0 0 0 0 0 default *default means read value when xstp bit is set to 1 by starting up from 0v, or supply voltage drop, etc. xsl bit the ? xsl bit is used t o select a crystal oscillator. set the ? xsl to0(default) to use 32. 768khz set ? xsl to1to use 32khz. f6 to f0 the time trimming circuit adjust one second count based on this readings when second digit is 00,20, or 40 seconds. normally, counting up to seconds is made once per 32,768 of clock pulse (or 32,000 when 32.000khz crys tal is used) generated by the oscillator. setting data to this register activates the time trimming circuit. register counts will be incremented as (( f5,f4,f3,f2,f1,f0) - 1) x2 when f6 is set to 0. register counts will be incremented as ((f5, f4, f3, f2, f1, f0) - 1) x2 when f6 is set to 0. register counts will be decremented as (( ? f5, ? f4, ? f3, ? f2, ? f1, ? f0)+1) x2 when f6 is set to 1. counts will not change when (f6, f5, f4, f3, f2, f1, f0) are set to (*, 0, 0, 0, 0, 0, *).
ace 5372 low power real - time clock (rtc) ver 1. 3 8 for example, when 32.768kh z crystal is used. when (f6, f5, f4, f3, f2, f1, f0) are set to (0,1, 0, 1, 0, 0,1), counts will change as: 32768+ 29 - 1 *2=32824 (clock will be delayed) when second digit is 00, 20, or 40.when (f6, f5, f4, f3, f2, f1, f0) are set to (0, 0, 0, 0, 0, 0, 1), counts will remain 32,768 without changing when second digit is 00, 20, or 40. when (f6, f5, f4, f3, f2, f1, f0) are set to (1,1,0,1,0,0,1), counts will change as: 32768+ - 17+1 *2=32736 (clock will be advanced) when second digit is 00, 20, or 40. adding 2 clock pulses every 20 seconds: 2/ 32768*20 =3.051ppm (or 3.125ppm when 32.000khzcrystal is used), delays the clock by approx. 3ppm. likewise, decrementing 2 clock pulses advances the clock by 3ppm. thus the clock may be adjusted to the precision of1.5pp m. note that the time trimming function only adjusts clock timing and oscillation frequency but 32.768khz clock output is not adjusted. 5. alarm register (alarm - a : internal address 8 - ah; alarm - b : internal address b - dh) alarm - a minute register (at intern al address 8h) d7 d6 d5 d4 d3 d2 d1 d0 operation - am40 am20 am10 am8 am4 am2 am1 write 0 am40 am20 am10 am8 am4 am2 am1 read 0 undefined undefined undefined undefined undefined undefined undefined default alarm - b minute register (at internal address bh) d7 d6 d5 d4 d3 d2 d1 d0 operation - bm40 bm20 bm10 bm8 bm4 bm2 bm1 write 0 bm40 bm10 bm10 bm8 bm4 bm2 bm1 read 0 undefined undefined undefined undefined undefined undefined undefined default alarm - a hour register (at internal address 9h) d7 d6 d5 d4 d3 d2 d1 d0 operation - - ah20,ap/ ? ? ? ?
ace 5372 low power real - time clock (rtc) ver 1. 3 9 alarm - a day - of - week register (at internal address ah) d7 d6 d5 d4 d3 d2 d1 d0 oper ation - aw6 aw5 aw4 aw3 aw2 aw1 aw0 write 0 aw6 aw5 aw4 aw3 aw2 aw1 aw0 read 0 undefined undefined undefined undefined undefined undefined undefined default alarm - b day - of - the - week register (at internal address dh) d7 d6 d5 d4 d3 d2 d1 d0 operatio n - bw6 bw5 bw4 bw3 bw2 bw1 bw0 write 0 bw6 bw5 bw4 bw3 bw2 bw1 bw0 read 0 undefined undefined undefined undefined undefined undefined undefined default *default means read value when xstp bit is set to 1 by starting up from 0v, or supply voltage dro p, etc. * alarm - a, alarm - b hour register d5 is set to 0 for am and 1 for pm in the 12 - hour display system. the register d5 indicates 10 digit of hour digit in 24 - hour display system. * to activate alarm operation, any imaginary alarm time setting sh ould not be left to avoid un - matching. * in hour digit display midnight is et to 12 , noon is set to 32 in 12 - hour display system. * aw0 to aw6 (bw0 to bw6) correspond to the day - of - the - week counter being set at (0,0,0) to (1,1,0). no alarm pulses are o utput when all of aw0 to aw6 (bw0 to bw6) are set to 0 example of alarm time settings alarm time settings day - of - the - week 12 - hour system 24 - hour system sun mon tue wed thu fri sat 10h 1h 10m 1m 10h 1h 10m 1m 00:00am every day 1 1 1 1 1 1 1 1 2 0 0 0 0 0 0 05:27am every day 1 1 1 1 1 1 1 0 5 2 7 0 5 2 7 11:59am every day 1 1 1 1 1 1 1 1 1 5 9 1 1 5 9 00:00pm on mon thru fri 0 1 1 1 1 1 0 3 2 0 0 1 2 0 0 05:56pm on wed 0 0 0 1 0 0 0 2 5 5 6 1 7 5 6 11:59pm on tue, thu, and sat 0 0 1 0 1 0 1 3 1 5 9 2 3 5 9
ace 5372 low power real - time clock (rtc) ver 1. 3 10 6. c ontrol register 1 ( at internal address eh) d7 d6 d5 d4 d3 d2 d1 d0 operation aale bale sl2 sl1 test ct2 ct1 ct0 write aale bale sl2 sl1 test ct2 ct1 ct0 read 0 0 0 0 0 0 0 0 default *the default means read value when xstp bit is set to 1 by starting up from 0v, or supply voltage drop, etc. aale , bale alarm - a, alarm - b enable bits aale operation 0 0 outputs alarm - a, alarm - b, int to the intra. outputs 32k clock pulses to the intrb. default 0 1 outputs alarm - a, int to the intra. outputs 32k clock pulses, alarm - b to the intrb. 1 0 outputs alarm - a, alarm - b to the intra. outputs 32k clock pulses, int to the intrb. 1 1 outputs alarm - a to the intra. outputs 32k clock pulses, alarm - b, int to the intrb. by setting sl1 and sl2 bits, two alarm pulses (alarm - a, alarm - b), periodic interrupt output (in t), 32k clock pulses may be output to the intra or intrb pins selectively. test ace5372 test bit test description operation 0 ordinary operation mode default 1 test mode
ace 5372 low power real - time clock (rtc) ver 1. 3 11 ct2, ct1, ct0 periodic interrupt cycle select bit ct2 ct1 ct0 descripti on wave form mode cycle and intra st day 00 a.m. 00 minute 00 second of every month pulse mode:l duration of output pulses may change in the maxi mum rang e of 3.784ms (3.875ms when 32khz crystal is used). for example, duty will be 500.3784% (or 500.3875% when 32khz crystal is used) at 1hz. level mode: frequency is one second may change in the maximum range of 3.784ms (3.875ms when 32khz crystal is used). relation between mode waveforms and crfg bit ? pulse mode
ace 5372 low power real - time clock (rtc) ver 1. 3 12 ? level mode 7. control register 2 ( at internal address fh ) d7 d6 d5 d4 d3 d2 d1 d0 operation - - 12_/24 adj clen_ ctfg aafg bafg write 0 0 12_/24 xstp clen_ ctfg a afg bafg read 0 0 undefined 1 0 0 0 0 default *the default means read value when xstp bit is set to 1 by starting up from 0v, or supply voltage drop, etc. ? 12/24 ? 12/24 - hour time display system selection bit ? being set this bit at 0 indicates 12 - hour display system while 1 indicates 24 - hour system. time display digit table 24 - hour time display system 12 - hour time display system 24 - hour time display system 12 - hour time display system 00 12(am12) 12 32(pm12) 01 01(am1) 13 21(pm1) 02 02(am2) 14 22(pm2) 03 03(am3) 15 23(pm3) 04 04(am4) 16 24(pm4) 05 05(am5) 17 25(pm5) 06 06(am6) 18 26(pm6) 07 07(am7) 19 27(pm7) 08 08(am8) 20 28(pm8) 09 09(am9) 21 29(pm9) 10 10(a m10) 22 30(pm10) 11 11(am11) 23 31(pm11)
ace 5372 low power real - time clock (rtc) ver 1. 3 13 either the 12 - hour or 24 - hour time display system should be selected before writing time data. adj 30 second adjust bit adj description 0 ordinary operation 1 second digit adjustment * the following operatio ns are performed by setting the second adj bit to 1 1) for second digits ranging from 00 to 29 seconds time counters smaller than seconds are reset and second digits are set to 00. 2) for second digits ranging from 30 to 59 seconds: time counters smal ler than seconds are reset and second digits are set to 00. minute digits are incremented by 1. * second digits are adjusted within 122us(within 125us: when 32khz crystal is used) from writing operation to adj. the adj bit is for write only and allows n o read operation. xstp oscillator halt sending bit xstp description operation 0 ordinary oscillation 1 oscillator halt sensing default the xstp bit senses the oscillator halt. * when oscillation is halted after initial power on from 0v or drop in sup ply vo ltage the bit is set to 1 and which remains to be 1 after it is restarted. this bit may be used to judge validity of clock and calendar count data after power on or supply voltage drop. * when this bit is set to 1, ? xsl f6 to f0 ct2 ct1 ct0 aal e bale sl2 sl1 ? clen and test bits are reset to 0. ? intra will stop output and the ? intrb will output 32khz clock pulses. the xstp bit is set to 0 by setting the control register 2 (address fh) during ordinary oscillation. clen 32 khz clock output bit ? by setting this bit to 0, output of clock pulses of the same frequency as the crystal oscillator is enabled. ctfg periodic interrupt flag bit ctfg descr iption operation 0 periodic interrupt output=off default 1 periodic interrupt output=on
ace 5372 low power real - time clock (rtc) ver 1. 3 14 this bit is set to 1 when periodic interrupt pulses are output ( ? intra or ? intrb= l). the ctfg bit may be set only to 0 in the interrupt level mode. setting this bit to 0 sets either the ? intra or the ? intrb to off (h). when this bit is set to 1 nothing happens. aafg, bafg alarm - a, alarm - b flag bit alarm - a the alarm interruption is enabled only when the aale, bale bits are set to 1. this bit turns to 1 when matched time is sensed for each alarm. * the aafg, bafg bit may be set only to 0. setting this bit to 0 sets e ither the ? intra or the ? intrb to the off h. when this bit is set to 1 nothing happens. when the aale, bale bit is set to 0, alarm operation is disabled and 0 is read from the aafg, bafg bit. output relationships between aafg bafg bit and ? intra ? intrb
ace 5372 low power real - time clock (rtc) ver 1. 3 15 transmission system of interface communication protocol determines: circuits in the equipment which sends data through sda bus are regarded as emitters, contrarily, circuits in the equipment which rec eives data through sda bus are regarded as receivers. master equipment and master circuit control data transmission; slave circuit is controlled. typical system bus structure data validity protocol data transmission protocol determines: transmit one bit data in every clock cycle. sda must be kept at a certain state while scl is at the h state as shown below during data transmission. start and stop conditions the scl and sda pins are at the h level when no data transmission is made. chang ing the sda from h to l when the scl and the sda are h activates the start condition and access is started. changing the sda from l to h when the scl is h activates stop condition and accessing stopped. start and stop conditions
ace 5372 low power real - time clock (rtc) ver 1. 3 16 as the arrival of the start condition, master emitter must send out an address command bit, which includes slave address and r/w model; when a certain receiver in bus is chosen, it will send ack signal and sda changes into low voltage. ack signal indicat es the success of data transmission. when scl clock drops, emitter sends continuously 8 bits and releases the data bus (sda changes into high voltage). the slave address the high effective 7 bits (bit7 --- bit1) in the address byte are defined as de vice type id. in ace 5372, these 7 bits are 0110010. the lowest bit0 is defined as r/w model. when this bit is 1 , it is read model, while 0 is write model. the slave address bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 0 1 1 0 0 1 0 r/w bit7 - bit1 : the sla ve address of the ace5372 is defined as 0110010 bit0 : r/w definition 1 is read model 0 is write model data transmission format in the interface communication interface generates no chip enable signals. in place of it each device has a 7bit slave add ress allocated. the first 1byte is allocated to this 7bit of slave address and to the command (r/ ? w) for which data transmission direction is designated b the data transmission thereafter. the slave address of the ace 5372 is specified at (0110010). at t he end of data transmission/receiving stop condition is generated to complete transmission. however, if start condition is generated without generating stop condition, repeated start condition is met and transmission/receiving data may be continued by sett ing the slave address again. use this procedures when the transmission direction needs t be changed during one transmission. data is written into the slave from the master s 0 1 1 0 0 1 0 0 a data a data a p slave address write
ace 5372 low power real - time clock (rtc) ver 1. 3 17 when data is read from the slave immediately after 7bit addressing from the master s 0 1 1 0 0 1 0 1 a data a data a_ p slave address read when the transmission direction is to be changed during transmission data transmission write format i n the ace 5372 a) first send 7 address bit(0110010), the eighth bit is write command 0. b) when the ninth bit is ack signal, ace 5372 is under writing condition. c) in the following byte, the high 4 bits are determined as internal address in ace 5372(0h - fh), the low 4 bits are transmission model. d) after another bits ack signal, it starts writing data normally. e) after writing 1 byte data, there will be 1 bit ack signal and then writing data in next 1 byte starts. only when there is a stop signal in the bit after ack signal, can the writing operation be stopped. example of data writing (when writing to internal address 4h to 5h) cpu to ace5372 ace5372 to cpu acknowledge signal start condition stop condition
ace 5372 low power real - time clock (rtc) ver 1. 3 18 data transmission read format in the ace 5372 the ace 5372 allows the following three readout methods of dat a from an internal register. i) the first method to reading data from the named internal address a)the first three steps are the same as write model b)after one bit ack signal, a new start signal will be produced to change the direction of data transmissi on in interface connection. c)then send 7 address bit(0110010), the eighth bit command is 1, ace 5372 is under data re ading condition. d) after another bits ack signal, it starts reading data normally. e)when a byte data is read and cpu sends 1 bit ack signal, a next byte data can be read. only when the 1 bit ack signal which is sent by cpu is high voltage, can the re ading operation be stopped and then cpu sends stop signals. example 1 of data read (when data is read from 7h to 9h) cpu to ace5372 ace5372 to cpu acknowledge signal start signal stop signal repeat start signal inform ace5372 to stop read
ace 5372 low power real - time clock (rtc) ver 1. 3 19 ii) the second method to reading data from the internal register is to start immediately after writing to the internal address pointer and the transmission format register. set 4h to the transmission format register when this method is u sed. example 2 of data read (when data is read from internal address dh to 0h) ii i) the third method to reading data from the internal register is to start reading immediately after writing to the slave address(0110010) and the ( r/ ? w) bit. since the internal address pointer is set to fh by default , this method is only effective when reading is started from the internal address fh. example 3 of data read (when data is read from internal address fh to 3h). data transm ission under special condition the ace 5372 hold the clock tentatively for duration from start condition to stop condition to avoid invalid read or write clock on carrying clock. to prevent invalid read or write clock shall be made during one transmission o peration. when 0.5 to 1.0 seconds elapses after start condition any access to the ace 5372 is automatically released to release tentative hold of the clock and access from the cpu is forced to be terminated (automatic resume function from the interface). a lso a second start condition after the first condition and before the stop condition is regarded as the repeated start condition. therefore, when 0.5 to 1.0 seconds passed after the first start condition, access to the ace 5372 is automatically released. cpu to ace5372 ace5372 to cpu acknowledge signal start signal stop signal repeat start signal cpu to ace5372 ace5372 to cpu acknowledge signal start signal stop signal repeat start signal inform ace5372 to stop read
ace 5372 low power real - time clock (rtc) ver 1. 3 20 the user shall always be able to access the real - time clock as long as the following two conditions are met. 1) no stop condition shall be generated until clock read/write is started and completed. 2) one cycle read/write operation shall be completed within 0.5 seconds. bad example of reading from seconds to hours (invalid read) (start condition) (read of seconds) (read of minutes) (stop condition) (start condition) (read of hour) (stop condition) assuming read was started at 09:59:59pm, and whi le reading seconds and minutes the time advanced to 10:00:00 pm. at this time second digit is hold so the read as 59:59. ace 5372 confirms (stop condition) and carry second digit being hold and the time changes to 10:00:00 pm. then, when the hour digit is r ead, it changes to 10. the wrong results of 10:59:59 will be read. configuration of oscillating circuit and time trimming circuit a) in general crystal oscillators are classified by their central frequen cy of cl (load capacitance) and available further gr ouped in several ranks as 10 20 and 50ppm of fluctuations in precision. b) the fluctuation of ic circuit frequency is 5~10ppm at room temperature. c) here, the clock accuracy at room temperature varies along with the variation of the characteristic of cr ystal oscillator. configuration of oscillating circuit because the adjustment of crystal oscillator frequency is also the adjustment of clock frequency, so the former adjustment can be done through c in & c out on the both sides of crystal. ace 5372 clock co operates with c in & c out , so oscillator frequency can be referred to crystal c l . general, relation between c l and c in or c out is as follo ws c s board floating capacitance if crystal oscillator frequency is on the higher side, the cl should be decreased, contrarily, the cl should be increased. cs cout cin cout cin cl ? ? ? *
ace 5372 low power real - time clock (rtc) ver 1. 3 21 according to this standard, the best cl is chosen to adjust frequency and cloc k frequency. for example: if the frequency is on the higher side, it can be lowed by attaching a c gout capacitor. * c gout 0~15pf time trimming circuit using the time trimming circuit gain or lose of clock may be adjusted with high precisio n by changing clock pulses for one second every 20 seconds. 1. when oscillation frequency *1 > target frequency *2 clock gain adjustment amount *3 = = (oscillation frequency C target frequency) x 10 +1 *1) oscillation frequency: clock frequency o utput from the ? intrb pin *2) target frequency: typ. 32.768khz to 32.000khz *3) adjustment amount: a value to be set finally to f6 to f0 bits. this value is expressed in 7 bit binary digits with sign bit (twos compliment). 2. when oscillation frequency = target frequency (no clock gain or loss) set the adjustment value to 0 or +1, or C 64, or C 63 to disable adjustment. 3. when oscillation frequency < target frequency (clock losses) adjustment amount = = (oscillation frequency C target frequ ency) x 10 ace5372 ) 20 * arg ( 2 * ) 1 . 0 arg ( y etfrequenc t nfrequency oscillatio y etfrequenc t frequency oscilation ? ? ) 20 * arg ( 2 * ) arg ( y etfrequenc t nfrequency oscillatio y etfrequenc t frequency oscilation ?
ace 5372 low power real - time clock (rtc) ver 1. 3 22 example of calculations 1) when oscillation frequency = 32770khz; target frequency = 32768khz adjustment value = 32770 - 32768+0.1 /(32770*2/(32768*20)) =(32770 - 32768)*10+1=21 set f6 f5 f4 f3 f2 f1 f0 = 0 0 1 0 1 0 1 2) when os cillation frequency =32762khz; target frequency = 32768khz adjustment value = 32762 - 32768 /(32762*2/(32768*20)) = (32762 - 32768)*10= - 60 to express C 60 in 7bi binary digits with sign bit ( twos compliment) subtract 60(3ch) from 128(80h) in th e above case, 80h - 3ch=44h thus set f6 f5 f4 f3 f2 f1 f0 = 1 0 0 0 1 0 0 after adjustment, adjustment error against the target frequency will the approx. 1.5ppm at a room temperature. notice: 1) clock frequency output from the ? intrb pin will change after adjustment by the clock adjustment circuit. 2) adjustment range: a)when oscillation frequency is higher than target frequency, the range of adjustment values is f6 f5 f4 f3 f2 f1 f0 = 0 0 0 0 0 0 1 to (0 1 1 1 1 1 1) and actual adjustable amount shall be - 3.05ppm to C 189.2ppm ( - 3.125ppm to 193.7ppm for 32000hz crystal). b) when oscillation frequency is lower than target frequency, the range of adjustment values is f6 f5 f4 f3 f2 f1 f0 = 1 1 1 1 1 1 1 to 1 0 0 0 0 1 0 and actual adjustable amount shal l be 3.05ppm to 189.2ppm (3.125ppm to 193.7ppm for 32000hz crystal) output waveforms the following three output waveforms can be output from the ? intra ( ? intrb) pin. 1 alarm interrupt when a registered time for alarm (such as day - of - the - week, hour or mi nute) coincide with calendar counter (such as day - of - the - week, hour or minute) interrupt to the cpu are requested with the output pin being on l. alarm interrupt consists of alarm_a and alarm_b, both have equivalent functions. 2 periodic interrupt outpu ts an output waveform selected by setting the periodic interrupt frequency select bit. waveforms include pulse mode and level mode. 3 32khz clock output clock pulses generated in the oscillation circuit are output as they are.
ace 5372 low power real - time clock (rtc) ver 1. 3 23 control of the ? ? of the three output wave forms listed above, interrupt output conditions may be set by setting the flag bit that monitors output state on the register, the enable bit that enables an ou tput wave form and the output select bit that selects either ? intra or ? intrb to be output. flag bit enable bit interrupt output select bit sl2 sl1 (d5 d4 at eh) 0 0 0 1 1 0 1 1 alarm_a aafg (d1 at fh) aale (d7 at eh) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? * when power on (xstp=1) since aale=bale=ct2=ct1=ct0= ? clen=sl2=sl1=0, ? intra=off (h) and 32khz clock pulses are output from the ? intrb pin. w hen more than one output waveforms are output from a single output pin, the output will have or wave form of negative logic of both. alarm interrupt for setting an alarm time, designated time such as day - of - the - week, hour or minute should be set to the alarm registers being aale bale bit to 0. after that set the aale bale bit to 1, from this moment onward when such registered alarm time coincide the value of calendar counter the ? intra ( ? intrb) comes down to l (on). the ? intra ( ? intrb) output c an be controlled by operating to the aale (bale) and aafg (bafg) bits.
ace 5372 low power real - time clock (rtc) ver 1. 3 2 4 periodic (clock) interrupt the ? intra ( ? intrb) pin output, the periodic interrupt cycle select bits (ct2, ct1, ct0) and the interrupt output select bits (sl2, sl1) can be used to interrupt the cpu in a certain cycle. the periodic interrupt cycle select bits can be used to select either one of two interrupt output modes: the pulse mode and the level mode. 1) pulse mode: output 2hz, 1hz clock pulses. for relationships with counting up of seconds see the diagram below. in the 2hz clock pulse mode, 0.496s clock pulses and 0.504s clock pulse are output alternatively. duty cycle for 1hz clock pulses becomes 50.4%. 2) level mode: one second, one minute one month may be selected for an interrupt cycle. counting up of seconds is matched with falling edge of interrupt output. 3) when the time trimming circuit is used, periodic interrupt cycle changes every 20 seconds. pulse mode: l duration of output pulses may change in the maximum ra nge of 3.784ms (3.875ms when 32khz crystal is used) ct2 ct1 ct0 description wave form mode cycle and intra(in trb) falling timing 0 0 0 - intra fixed at l
ace 5372 low power real - time clock (rtc) ver 1. 3 25 for example, duty will be 500.3784% (or 500.38 75% when 32khz crystal is used) a t 1hz. level mode: frequency in one second may change in the maximum range of 3.784ms (3.875m s when 32khz crystal is used). relation between mode waveforms and crfg bit ? pulse mode ? level mode 32khz clock output the crystal oscillator can generate clock pulses of 32khz from the ? intrb pin. the pin is changed to h by setting the ? clen bit to 1. * 32khz clock pulse output will not be affected from settings in the clock adjustment register. when power on (xstp=1), 32khz clock pulses are output from the ? intrb pin. oscillator halt sensing oscillation halt can be sensed through m onitoring the xstp bit with preceding setting of the xstp bit to 0 by writing data to the control register 2.upon oscillator halt sending, the xstp bit is switched from 0 to 1. this function can be applied to judge clock data validity. when the xstp bit is 1, ? xsl, f6 to f0, ct2, ct1, ct0, aale, bale, sl2, sl1, ? clen and test bits are reset to 0. *1 the xstp bit is set to 1 upon power - on from 0v. note that any instantaneous power disconnection may cause operation failure. *2 once oscillation halt has been sensed, the xstp bit is held at 1 even if oscillation is restarted. ensure error - free osci llation half sensing by preventing the following events: 1) instantaneous disconnection of vdd 2) condensation on the crystal oscillator 3) generation of noise on the pcb in the crystal oscillator 4) application of voltage exceeding prescribed maximum ratings to the i ndividual pins of the ic
ace 5372 low power real - time clock (rtc) ver 1. 3 26 dc characteristics t opt = - 40 to +85 , gnd=0v, vdd=3.6v, f osc =32,768hz or 32,000hz symbol item pin name conditions m in . t yp . m ax . unit vih h input voltage scl, sda 0.8v dd 6.0 v vil l input voltage scl, sda - 0.3 0.3vdd v iol1 l output current intra, intrb vol1=0.4v 1 ma iol2 sda vol2=0.6v 7 ma iilk input leakage current scl vi=6vorgnd vdd=6v - 1 1 ua vdd operating voltage vdd gnd 1.8 5.5 v counting voltage 1.2 5.5 v ioz output off state leakage current sda, intra, intrb vo=6vorgnd vdd=6v - 1 1 ua idd stand by current vdd vdd=5v, topt=25 scl,sda=5v 0.4 ua ac characteristics characteristics parameter t a = - 40 to +85 v dd =4.5v to 5.5v symbol item conditions m in . m ax . unit f scl scl clock frequency 0 100 khz t low scl clock l time 4.7 us t high scl clock h time 5 us t buf bus release time before next data is transmitted 4.7 us t su:sta start condition setup time 4.7 us t su:sto stop condition setup time 4.7 us t hd:sta start condition hold time 4 us t hd:sto stop condition hold time 4 us t su:dat data setup time 250 ns t hd:dat data input hold time 0 ns t hd data output hold time scl negedge to sda data changes 0 ns t aa clock output scl negedge to sda data availed 0.3 3.5 us t r rising time of scl and sda (input) 1 us t f falling time of scl and sda (input) 30 0 ns t i spike width that can be removed with 100 ns
ace 5372 low power real - time clock (rtc) ver 1. 3 27 input filter absolute maximum ratings typical applications example of circuit ac e5372 ace5372 (a) (b) 1. mount the high - and low - frequency by - pass capacitors c0 and c1 (typ. c1=10uf, c2=0.1uf) 2. the typical volume of pull - up resistance r0~r3 is 10k 3. batt and vccs voltage: v batt v vcc 4. connect the pull - up resistor of the intra pin or the intrb pin to two different positions depending battery back - up: symbol item conditions ratings unit vdd supply voltage - 0.3 to +7.0 v vi input voltage scl ace5372 ace5372
ace 5372 low power real - time clock (rtc) ver 1. 3 28 a . when the spare battery supplies power, intra (b) is not used. b . when the spare battery supp lies power, intra (b) is used. example of interface circuit to the cpu ace5372
ace 5372 low power real - time clock (rtc) ver 1. 3 29 package information sop - 8 symbol mm inches min t yp . max min t yp . max a 1.35 - 1.75 0.053 - 0.069 a1 0.10 - 0.25 0.004 - 0.010 b 0.33 - 0.51 0.013 - 0.020 c 0.19 - 0.25 0.007 - 0.010 d 4.80 - 5.00 0.189 - 0.197 ddd - - 0.10 - - 0.004 e 3.80 - 4.00 0.150 - 0.157 e - 1.27 - - 0.050 - h 5.80 - 6.20 0.228 - 0.244 h 0.25 - 0.50 0.010 - 0.0 20 l 0.40 - 0.90 0.016 - 0.035 0 o - 8 o 0 o - 8 o
ace 5372 low power real - time clock (rtc) ver 1. 3 30 package information t s s o p - 8 d imensions (mm are the original dimensions) u nit h e l lp v w y z (1) 0 0 0 notes : 1.p lastic or metal protrusions of 0.15mm maximum per side are not included 2.plastic or metal protrusions of 0.25mm maximum per side are not included u nit a max. a1 a2 a3 bp c d (1) e (2) e mm 1.10 0.15 0.05 0.95 0.80 0.25 0.32 0.12 0.25 0.10 3.10 2.90 4.60 4.20 0.65
ace 5372 low power real - time clock (rtc) ver 1. 3 31 notes ace does not assume any responsibility for use as critical components in life support devices or systems without the express written approval of the president and general counsel of ace electronics co., ltd. as s ued herein: 1. life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and shoes failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. a critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. ace technology co., ltd. http://www.ace - ele.com/

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