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ht1380/ht1381 serial timekeeper chip block diagram pin assignment 1 september 18, 2000 features operating voltage: 2.0v~5.5v maximum input serial clock: 500khz at v dd =2v, 2mhz at v dd =5v operating current: less than 400na at 2v, less than 1.2 aat5v ttl compatible v ih : 2.0v~v dd +0.3v at v dd =5v v il : 0.3v~+0.8v at v dd =5v two data transmission modes: single-byte, or burst mode serial i/o transmission all registers store bcd format ht1380: 8-pin dip package ht1381: 8-pin sop package general description the ht1380/ht1381 is a serial timekeeper ic which provides seconds, minutes, hours, day, date, month and year information. the number of days in each month and leap years are auto - matically adjusted. the ht1380/ht1381 is de - signed for low power consumption and can operate in two modes: one is the 12-hour mode with an am/pm indicator, the other is the 24-hour mode. the ht1380/ht1381 has several registers to store the corresponding information with 8-bit data format. a 32768hz crystal is required to provide the correct timing. in order to minimize the pin number, the ht1380/ht1381 use a se - rial i/o transmission method to interface with a microprocessor. only three wires are required: (1) rest , (2) sclk and (3) i/o. data can be de- livered 1 byte at a time or in a burst of up to 8 bytes. applications microcomputer serial clock clock and calendar

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pad assignment pad coordinates unit: m pad no. x y 1 851.40 775.00 2 851.40 494.60 3 844.40 203.90 4 845.90 618.30 5 848.40 4.30 6 845.90 332.60 7 844.40 572.60 chip size: 2010 1920 ( m) 2 * the ic substrate should be connected to vss in the pcb layout artwork. pad description pad no. pad name i/o internal connection description 1 x1 i cmos 32768hz crystal input pad 2 x2 o cmos oscillator output pad 3 vss cmos negative power supply, ground 4 rest i cmos reset pin with serial transmission 5 i/o i/o cmos data input/output pin with serial transmission 6 sclk i cmos serial clock pulse pin with serial transmission 7 vdd cmos positive power supply absolute maximum ratings supply voltage.............................. 0.3v to 5.5v storage temperature................. 50 cto125 c input voltage .................v ss 0.3v to v dd +0.3v operating temperature ..................0 cto70 c note: these are stress ratings only. stresses exceeding the range specified under absolute maxi - mum ratings may cause substantial damage to the device. functional operation of this de - vice at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. ht1380/ht1381 2 september 18, 2000 *+ ,+ -

d.c. characteristics ta=25 c symbol parameter test conditions min. typ. max. unit v dd conditions v dd operating voltage 2 5.5 v i stb standby current 2v 100 na 5v 100 na i dd operating current 2v no load 0.7 1.0 a 5v 0.7 1.2 a i oh source current 2v v oh =1.8v 0.2 0.4 ma 5v v oh =4.5v 0.5 1.0 ma i ol sink current 2v v ol =0.2v 0.7 1.5 ma 5v v ol =0.5v 2.0 4.0 ma v ih h input voltage 5v 2 v v il l input voltage 5v 0.8 v f osc system frequency 5v 32768hz x tal 32768 hz f sclk serial clock 2v 0.5 mhz 5v 2 mhz i stb is specified with sclk, i/o, rest open. the clock halt bit must be set to logic 1 (oscillator disabled). a.c. characteristics ta=25 c symbol parameter test conditions min. max. unit v dd conditions t dc data to clock setup 2v 200 ns 5v 50 t cdh clock to data hold 2v 280 ns 5v 70 t cdd clock to data delay 2v 800 ns 5v 200 t cl clock low time 2v 1000 ns 5v 250 t ch clock high time 2v 1000 ns 5v 250 f clk clock frequency 2v 0.5 mhz 5v d.c. 2.0 ht1380/ht1381 3 september 18, 2000
symbol parameter test conditions min. max. unit v dd conditions t r clock rise and fall time 2v 2000 ns t f 5v 500 t cc reset to clock setup 2v 4 us 5v 1 t cch clock to reset hold 2v 240 ns 5v 60 t cwh reset inactive time 2v 4 us 5v 1 t cdz reset to i/o high impedance 2v 280 ns 5v 70 ht1380/ht1381 4 september 18, 2000 functional description the ht1380/ht1381 mainly contains the fol - lowing internal elements: a data shift register array to store the clock/calendar data, com - mand control logic, oscillator circuit and read timer clock. the clock is contained in eight read/write registers as shown below. data con - tained in the clock register is in binary coded decimal format. two modes are available for transferring the data between the microprocessor and the ht1380/ht1381. one is in single-byte mode and the other is in multiple-byte mode. the ht1380/ht1381 also contains two addi - tional bits, the clock halt bit (ch) and the write protect bit (wp). these bits control the opera - tion of the oscillator and so data can be written to the register array. these two bits should first be specified in order to read from and write to the register array properly. command byte for each data transfer, a command byte is initiated to specify which register is accessed. this is to determine whether a read, write, or test cycle is operated and whether a single byte or burst mode transfer is to occur. refer to the table shown below and follow the steps to write the data to the chip. first give a command byte of ht1380/ht1381, and then write a data in the register. this table illustrates the correlation between command byte and their bits: command byte function description c7 c6 c5 c4 c3 c2 c1 c0 select read or write cycle r/w specify the register to be accessed a2 a1 a0 clock halt flag c for ic test only 1001xxx1 select single byte or burst mode 1011111x note: x stands for don t care
ht1380/ht1381 5 september 18, 2000 the following table shows the register address and its data format: register name range data register definition address a2~a0 bit r/w command byte d7 d6 d5 d4 d3 d2 d1 d0 seconds 00~59 ch 10 sec sec 000 w r 10000000 10000001 minutes 00~59 0 10 min min 001 w r 10000010 10000011 hours 01~12 00~23 12\ 24 0 0 ap 10 hr hr hour 010 w r 10000100 10000101 date 01~31 0 0 10 date date 011 w r 10000110 10000111 month 01~12 0 0 0 10m month 100 w r 10001000 10001001 day 01~07 0 0 0 0 day 101 w r 10001010 10001011 year 00~99 10 year year 110 w r 10001100 10001101 write protect 00~80 wp always zero 111 w r 10001110 10001111 ch: wp: clock halt bit ch=0 oscillator enabled ch=1 oscillator disabled write protect bit wp=0 register data can be written in wp=1 register data can not be written in bit 7 of reg2: bit 5 of reg2: 12/24 mode flag bit 7=1, 12-hour mode bit 7=0, 24-hour mode am/pm mode defined ap=1 pm mode ap=0 am mode r/w signal the lsb of the command byte determines whether the data in the register be read or be written to. when it is set as 0 means that a write cycle is to take place otherwise this chip will be set into the read mode. a0~a2 a0 to a2 of the command byte is used to specify which registers are to be accessed. there are eight registers used to control the month data, etc., and each of these registers have to be set as a write cycle in the initial time. burst mode when the command byte is 10 111110 (or 10111111), the ht1380/ht1381 is configured in burst mode. in this mode the eight clock/calen - dar registers can be written (or read) in series, starting with bit 0 of register address 0 (see the timing on the next page). test mode when the command byte is set as 1001xxx1, ht1380/ht1381 is configured in test mode. the test mode is used by holtek only for testing purposes. if used generally, unpredictable con - ditions may occur.
ht1380/ht1381 6 september 18, 2000 write protect register this register is used to prevent a write opera - tion to any other register. data can be written into the designated register only if the write protect signal (wp) is set to logic 0. the write protect register should be set first before re - starting the system or before writing the new data to the system, and it should set as logic 1 in the read cycle. the write protect bit cannot be written to in the burst mode. clock halt bit d7 of the seconds register is defined as the clock halt flag (ch). when this bit is set to logic 1, the clock oscilla - tor is stopped and the chip goes into a low-power standby mode. when this bit is writ - ten to logic 0, the clock will start. 12-hour/24-hour mode the d7 of the hour register is defined as the 12-hour or 24-hour mode select bit. when this bit is in high level, the 12-hour mode is selected otherwise it s the 24-hour mode. am-pm mode these are two functions for the d5 of the hour register determined by the value d7 of the same register. one is used in am/pm selection on the 12-hour mode. when d5 is logic 1, it is pm, otherwise it s am. the other is used to set the second 10-hour bit (20~23 hours) on the 24-hour mode. reset and serial clock control the rest pin is used to allow access data to the shift register like a toggle switch. when the rest pin is taken high, the built-in control logic is turned on and the address/command se - quence can access the corresponding shift regis - ter. the rest pin is also used to terminate either single-byte or burst mode data format. the input signal of sclk is a sequence of a fall - ing edge followed by a rising edge and it is used to synchronize the register data whether read or write. for data input, the data must be read after the rising edge of sclk. the data on the i/o pin becomes output mode after the falling edge of the sclk. all data transfer terminates if the rest pin is low and the i/o pin goes to a high impedance state. the data transfer is il - lustrated on the next page. data in and data out in writing a data byte with ht1380/ht1381, the read/write should first set as r/w=0 in the command byte and follow with the correspond - ing data register on the rising edge of the next eight sclk cycles. additional sclk cycles are ignored. data inputs are entered starting with bit 0. in reading a data on the register of ht1380/ht1381, r/w=1 should first be en - tered as input. the data bit outputs on the fall - ing edge of the next eight sclk cycles. note that the first data bit to be transmitted on the first falling edge after the last bit of the read command byte is written. additional sclk cy- cles re-transmits the data bytes as long as rest remains at high level. data outputs are read starting with bit 0. crystal selection a 32768hz crystal can be directly connected to the ht1380/ht1381 via pin 2 and pin 3 (x1, x2). in order to obtain the correct frequency, two additional load capacities (c1, c2) are needed. the value of the capacity depends on how accurate the crystal is. we suggest that you can follow the table on the next page. . /

the following diagram shows the single and burst mode transfer: the table illustrates the values suggested for capacities c1, c2 part no. crystal error capacity value ht1380/ht1381
10ppm 5pf 10~20ppm 8pf operating flowchart to initiate any transfer of data, rest is taken high and an 8-bit command byte is first loaded into the control logic to provide the register address and command information. following the command word, the clock/calendar data is serially transferred to or from the corresponding register. the rest pin must be taken low again after the transfer operation is completed. all data enter on the rising edge of sclk and outputs on the falling edge of sclk. in total, 16 clock pulses are needed for a sin - gle byte mode and 72 for burst mode. both input and output data starts with bit 0. in using the ht1380/ht1381, set first the wp and ch to 0 and wait for about 3 seconds, the oscilla - tor will generate the clocks for internal use. then, choose either single mode or burst mode to input the data. the read or write operating flowcharts are shown on the next page. ht1380/ht1381 7 september 18, 2000 0 1+ 1 1 + + + +
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* in reading data byte from ht1380/ht1381 register, the first data bit to be transmitted at the first falling edge after the last bit of the command byte is written. ht1380/ht1381 8 september 18, 2000 1 # 7 ) 8 7 !&&!" " #$ 56 . 5%8 7 !&5*0 9 - 56#2 3 ! !/ ! #7)8 &!" " #$56+. #5%!&%%! 56#2 3 ! +!/ ! 1 5%8 7 !& 5#$#5%!&%%! $! 8 &! 7!#$# $ 5 6 # 8 5 + : #7)&!" " #$ 5 6 # 8 5 + 1 $! 8 %% $56*$5-# . #8 5+! + : #7)5) " !$ &!" " #$56*;3 ! ; 3 < - # 8 5 + 5%8 7 !& 5#$#5%!&%%! #! &&$ 4 ! 7# !" %!8 ! 7# !" !%!8 7# !" %!8 ! 7# !" !%!8 7 # ! " ! %! 8 7# !" %!8 ! 7# !" %!8 ! 7 # !" !%!8 to disable the write protect (wp=0) bit and enable the oscillator (ch=0) single byte data transfer burst mode data transfer
timing diagrams read data transfer write data transfer application circuits ht1380/ht1381 9 september 18, 2000
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ht1380/ht1381 10 september 18, 2000 copyright 2000 by holtek semiconductor inc. the information appearing in this data sheet is believed to be accurate at the time of publication. however, holtek assumes no responsibility arising from the use of the specifications described. the applications mentioned herein are used solely for the purpose of illustration and holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may pres - ent a risk to human life due to malfunction or otherwise. holtek s products are not authorized for use as critical com - ponents in life support devices or systems. holtek reserves the right to alter its products without prior notification. for the most up-to-date information, please visit our web site at http://www.holtek.com.tw. holtek semiconductor inc. (headquarters) no.3, creation rd. ii, science park, hsinchu, taiwan tel: 886-3-563-1999 fax: 886-3-563-1189 http://www.holtek.com.tw holtek semiconductor inc. (taipei sales office) 4f-2, no. 3-2, yuanqu st., nankang software park, taipei 115, taiwan tel: 886-2-2655-7070 fax: 886-2-2655-7373 fax: 886-2-2655-7383 (international sales hotline) holtek semiconductor inc. (shanghai sales office) 7th floor, building 2, no.889, yi shan rd., shanghai, china 200233 tel: 021-6485-5560 fax: 021-6485-0313 http://www.holtek.com.cn holtek semiconductor inc. (shenzhen sales office) 5/f, unit a, productivity building, cross of science m 3rd road and gaoxin m 2nd road, science park, nanshan district, shenzhen, china 518057 tel: 0755-8616-9908, 8616-9308 fax: 0755-8616-9533 holtek semiconductor inc. (beijing sales office) suite 1721, jinyu tower, a129 west xuan wu men street, xicheng district, beijing, china 100031 tel: 010-66410030, 66417751, 66417752 fax: 010-66410125 holtek semiconductor inc. (chengdu sales office) 709, building 3, champagne plaza, no.97 dongda street, chengdu, sichuan, china 610016 tel: 028-6653-6590 fax: 028-6653-6591 holmate semiconductor, inc. (north america sales office) 46729 fremont blvd., fremont, ca 94538 tel: 510-252-9880 fax: 510-252-9885 http://www.holmate.com

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