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ACE5372
Technology Description
Low Power Real-Time Clock (RTC)
The ACE5372 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 ACE5372 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 oscillator 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 based on signals from the CPU. The crystal oscillator may be selected from 32KHz or 32.768KHz types. It adopts 8-pin SOP or TSSOP package.
Features
* * * * * * * * * * * * *
Lowest supply current: 400nA TYP.@5V Connected to the CPU via only 2-wires (MAX. 100KHz) A clock counter (counting hours. Minutes. 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 register) 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 Package: 8pin SOP or TSSOP
Packaging Type
SOP-8
1 2 3 4 8 7 6 5 1 2 3 4
TSSOP-8
8 7 6 5
Pin Symbol Definition Value In/Out 1 INTRB Interrupt Output B 0~12V Out 2 SCL Serial Clock Line 0~5.5V In 3 SDA Serial Data Line 0~5.5V In/Out 4 GND Ground Power 0V Power 5 INTRA Interrupt Output A 0~12V Out 6 OSCOUT Oscillator Circuit Output 0~1.5V Out 7 OSCIN Oscillator Circuit Input 0~1.5V IN 8 VDD Supply Voltage 1.8~5.5V Power
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Technology Ordering information
Selection Guide ACE5372 XX + H Halogen - free Pb - free FM : SOP-8 TM: TSSOP-8
Low Power Real-Time Clock (RTC)
ACE5372
Block Diagram
VDD and GND
ACE5372
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.
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Technology Bypass Capacitance
Low Power Real-Time Clock (RTC)
ACE5372
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. It's recommended to choose the right crystal oscillator parameter referring to the supplier's 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 when choosing capacitance capacity in an oscillator circuit. To minimize output distortion, both crystal oscillator and capacitance should be installed as close to ACE5372 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 synchronize 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 SCL 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 ACE5372 a pull-up resistance must be connected with pins of INTRA and INTRB. INTRA could output periodic interrupt 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 (when 32.768KHz crystal is used).
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Technology Functional Descriptions
Allocation of Internal Addresses
Internal Address 0H 1H 2H 3H 4H 5H 6H 7H 8H 9H AH BH CH DH EH FH Contents Second Counter Minute Counter Hour Counter Day of the Week Counter Day Counter Month Counter Year Counter Time Trimming Register Alarm_A (Minute Register) Alarm_A (Hour Register) Alarm_A (Day of the Week Register) Alarm_B (Minute Register) Alarm_B (Hour Register) Alarm_B (Day of the Week Register) Control Register 1 Control Register 2
Low Power Real-Time Clock (RTC)
ACE5372
Function Counting and storing seconds in BCD codes Counting and storing minutes in BCD codes Counting and storing hours in BCD codes Counting and storing days of the week in BCD codes Counting and storing days in BCD codes Counting and storing months in BCD codes Counting and storing years in BCD codes Storing adjusting parameter and external select control of crystal oscillator Storing minutes in Timer A Storing hours in Timer A Storing days of the week in Timer A Storing minutes in Timer B Storing hours in Timer B Storing days of the week in Timer B Storing ring enable, interrupt output port select, and periodic interrupt cycle select information Storing time display select, interrupt and alarm signal, oscillator halt sensing information
Calendar Counter
The ACE5372 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 separately in registers from 0H to 6H.
High Precision time Trimming function
The ACE5372 has an internal oscillation circuit capacitance CGND and CVDD so that an oscillation circuit may be configured simply by externally connecting a crystal. The ACE5372 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.
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Technology Alarm function and Periodic Interrupt
Low Power Real-Time Clock (RTC)
ACE5372
Alarm Function: The ACE5372 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 separately at a specific time. The 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 theINTRA pin while the ALARM-B is output from either the INTRA or theINTRB pins. Polling is possible separately for each alarm function. Periodic Interrupt: The ACE5372 can output periodic interrupt pulses in addition to alarm function from the INTRA andINTRB 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 minute, every hour and every month) that are appropriate for CPU level Oscillation Halt Sensing The oscillation halt sending function uses a register (XSTP bit at internal address FH) to store oscillation halt information. This function may be used to determine 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 ACE5372 may output oscillation frequency from INTRB pin. This clock output is set 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 the12/24 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 0 0 D6 S40 S40 Undefined D5 S20 S20 Undefined D4 S10 S10 Undefined D3 S8 S8 Undefined D2 S4 S4 Undefined D1 S2 S2 Undefined D0 S1 S1 Undefined Operation Write Read Default
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Technology
Minute digit register ( at internal address 1H )
D7 0 0 D6 M40 M40 Undefined D5 M20 M20 Undefined D4 M10 M10 Undefined D3 M8 M8 Undefined D2 M4 M4 Undefined
Low Power Real-Time Clock (RTC)
ACE5372
D1 M2 M2 Undefined
D0 M1 M1 Undefined
Operation Write Read Default
Hour digit register ( at internal address 2H)
D7 0 0 D6 0 0 D5 H20 or P/A H20 or P/A Undefined D4 H10 H10 Undefined D3 H8 H8 Undefined D2 H4 H4 Undefined D1 H2 H2 Undefined D0 H1 H1 Undefined Operation Write Read Default
* 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-week 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 0 0 D6 0 0 D5 0 0 D4 0 0 D3 0 0 D2 W4 W4 Undefined D1 W2 W2 Undefined D0 W1 W1 Undefined Operation Write Read 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 address4-6H ) * 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 30 (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.
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Technology
Day digit register ( at internal address 4H )
D7 0 0 D6 0 0 D5 D20 D20 Undefined D4 D10 D10 Undefined D3 D8 D8 Undefined D2 D4 D4 Undefined D1 D2 D2 Undefined
Low Power Real-Time Clock (RTC)
ACE5372
D0 D1 D1 Undefined
Operation Write Read 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 0 0 D6 0 0 D5 0 0 D4 MO10 MO10 Undefined D3 MO8 MO8 Undefined D2 MO4 MO4 Undefined D1 MO2 MO4 Undefined D0 MO1 MO1 Undefined Operation Write Read 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 Y80 Y80 Undefined D6 Y40 Y40 Undefined D5 Y20 Y20 Undefined D4 Y10 Y10 Undefined D3 Y8 Y8 Undefined D2 Y4 Y4 Undefined D1 Y2 Y2 Undefined D0 Y1 Y1 Undefined Operation Write Read Default
*Default means read value when XSTP bit is set to "1" by starting up from 0V, or supply voltage drop, etc.
4. Time Trimming Register ( at internal address 7H )
D7 XSL_ XSL_ 0 D6 F6 F6 0 D5 F5 F5 0 D4 F4 F4 0 D3 F3 F3 0 D2 F2 F2 0 D1 F1 F1 0 D0 F0 F0 0 Operation Write Read 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 to select a crystal oscillator.Set the XSL to"0"(default) to use 32.768KHz Set XSL to"1"to 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 crystal 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, *).
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
For example, when 32.768KHz 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 of1.5ppm. 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 internal address 8H)
D7 0 0 D6 AM40 AM40 Undefined D5 AM20 AM20 Undefined D4 AM10 AM10 Undefined D3 AM8 AM8 Undefined D2 AM4 AM4 Undefined D1 AM2 AM2 Undefined D0 AM1 AM1 Undefined Operation Write Read Default
Alarm-B minute register (at internal address BH)
D7 0 0 D6 BM40 BM40 Undefined D5 BM20 BM10 Undefined D4 BM10 BM10 Undefined D3 BM8 BM8 Undefined D2 BM4 BM4 Undefined D1 BM2 BM2 Undefined D0 BM1 BM1 Undefined Operation Write Read Default
Alarm-A hour register (at internal address 9H)
D7 0 0 D6 0 D5 AH20,AP/A AH20,AP/A Undefined D4 AH10 AH10 Undefined D3 AH8 AH8 Undefined D2 AH4 AH4 Undefined D1 AH2 AH2 Undefined D0 AH1 AH1 Undefined Operation Write Read Default
Alarm-B hour register (at internal address CH)
D7 0 0 D6 0 0 D5 BH20,BP/A BH20,BP/A Undefined D4 BH10 BH10 Undefined D3 BH8 BH8 Undefined D2 BH4 BH4 Undefined D1 BH2 BH2 Undefined D0 BH1 BH1 Undefined Operation Write Read Default
Alarm-A day-of-week register (at internal address AH)
D7 0 0 D6 AW6 AW6 Undefined D5 AW5 AW5 Undefined D4 AW4 AW4 Undefined D3 AW3 AW3 Undefined D2 AW2 AW2 Undefined D1 AW1 AW1 Undefined D0 AW0 AW0 Undefined Operation Write Read Default
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Technology
Alarm-B day-of-the-week register (at internal address DH)
D7 0 0 D6 BW6 BW6 Undefined D5 BW5 BW5 Undefined D4 BW4 BW4 Undefined D3 BW3 BW3 Undefined D2 BW2 BW2 Undefined
Low Power Real-Time Clock (RTC)
ACE5372
D1 BW1 BW1 Undefined
D0 BW0 BW0 Undefined
Operation Write Read Default
*Default means read value when XSTP bit is set to "1" by starting up from 0V, or supply voltage drop, 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 should 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 output when all of AW0 to AW6 (BW0 to BW6) are set to "0" Example of Alarm Time Settings
Alarm Time Settings 00:00AM every day 05:27AM every day 11:59AM every day 00:00PM on Mon thru Fri 05:56PM on Wed 11:59PM on Tue, Thu, and Sat Day-of-the-week
Sun Mon Tue Wed Thu Fri Sat
12-hour system
10H 1H 10M 1M
24-hour system
10H 1H 10M 1M
1 1 1 0 0 0
1 1 1 1 0 0
1 1 1 1 0 1
1 1 1 1 1 0
1 1 1 1 0 1
1 1 1 1 0 0
1 1 1 0 0 1
1 0 1 3 2 3
2 5 1 2 5 1
0 2 5 0 5 5
0 7 9 0 6 9
0 0 1 1 1 2
0 5 1 2 7 3
0 2 5 0 5 5
0 7 9 0 6 9
6. CONTROL Register 1 (
D7 AALE AALE 0 D6 BALE BALE 0 D5 SL2 SL2 0 D4 SL1 SL1 0
at internal address EH )
D3 TEST TEST 0 D2 CT2 CT2 0 D1 CT1 CT1 0 D0 CT0 CT0 0 Operation Write Read Default
*The default means read value when XSTP bit is set to "1" by starting up from 0V, or supply voltage drop, etc.
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Technology
AALE , BALE ALARM-A, ALARM-B enable bits
AALEBALE 0 1 Description
Low Power Real-Time Clock (RTC)
ACE5372
Operation Default
ALARM-AALARM-B correspondence action invalid ALARM-AALARM-B correspondence action valid
L2, SL1 Interrupt output select bits
SL2 0 0 1 1 SL1 0 1 0 1 Description Outputs ALARM-A, ALARM-B, INT to the INTRA. Outputs 32K clock pulses to the INTRB. Outputs ALARM-A, INT to the INTRA. Outputs 32K clock pulses, ALARM-B to the INTRB. Outputs ALARM-A, ALARM-B to the INTRA. Outputs 32K clock pulses, INT to the INTRB. Outputs ALARM-A to the INTRA. Outputs 32K clock pulses, ALARM-B, INT to the INTRB. Operation Default
By setting SL1 and SL2 bits, two alarm pulses (ALARM-A, ALARM-B), periodic interrupt output (INT), 32K clock pulses may be output to the INTRA or INTRB pins selectively. TEST ACE5372 Test bit
TEST 0 1 Description Ordinary operation mode Test mode Operation Default
CT2, CT1, CT0 Periodic interrupt cycle select bit
CT2 0 0 0 0 1 1 1 1 CT1 0 0 1 1 0 0 1 1 CT0 0 1 0 1 0 1 0 1 Description Wave Form Mode Pulse Mode Pulse Mode Level Mode Level Mode Level Mode Level Mode Cycle and INTRAINTRBFalling Timing INTRAINTRBat high level INTRAINTRBat low level 2HzDuty 50% 1HzDuty 50% Every secondsynchronized with second count up Every minute00 second of every minute Every hour00 minute 00 second of every hour Every monththe 1st day 00 A.M. 00 minute 00 second of every month
1) Pulse mode: Outputs 2Hz, 1Hz clock pulses. For relationships with counting up of seconds see the diagram below.
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
In the 2Hz clock pulse mode, 0.496s clock pulses and 0.504s clock pulses are output alternatively. Duty cycle for 1Hz clock pulses becomes 50.4%. 2) Level mode: One second, one minute or 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 range 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
Level mode
7. Control Register 2 ( at internal address FH )
D7 0 0 D6 0 0 D5 12_/24 12_/24 Undefined D4 ADJ XSTP 1 D3 CLEN_ CLEN_ 0 D2 CTFG CTFG 0 D1 AAFG AAFG 0 D0 BAFG BAFG 0 Operation Write Read 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
12/24 0 1 Description 12-hour time display system 24-hour time display system
Being set this bit at "0" indicates 12-hour display system while "1" indicates 24-hour system.
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Technology
Time Display Digit Table
24-hour time display system 00 01 02 03 04 05 06 07 08 09 10 11 12-hour time display system 12(AM12) 01(AM1) 02(AM2) 03(AM3) 04(AM4) 05(AM5) 06(AM6) 07(AM7) 08(AM8) 09(AM9) 10(AM10) 11(AM11)
Low Power Real-Time Clock (RTC)
ACE5372
24-hour time display system 12 13 14 15 16 17 18 19 20 21 22 23
12-hour time display system 32(PM12) 21(PM1) 22(PM2) 23(PM3) 24(PM4) 25(PM5) 26(PM6) 27(PM7) 28(PM8) 29(PM9) 30(PM10) 31(PM11)
Either the 12-hour or 24-hour time display system should be selected before writing time data. ADJ 30 Second Adjust Bit
ADJ 0 1
1) 2)
Description Ordinary operation Second digit adjustment
For second digits ranging from "00" to "29" secondsTime counters smaller than seconds are reset and second digits are set to "00". For second digits ranging from "30" to "59" seconds: Time counters smaller than seconds are reset and second digits are set to "00". Minute digits are incremented by 1.
* The following operations are performed by setting the second ADJ bit to 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 no read operation. XSTP Oscillator Halt Sending Bit
XSTP 0 1 Description Ordinary oscillation Oscillator halt sensing default Operation
The XSTP bit senses the oscillator halt.
* When oscillation is halted after initial power on from 0V or drop in supply voltage 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", XSLF6 to F0CT2CT1CT0AALEBALESL2SL1CLEN 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.
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Technology
CLEN 32KHz Clock Output Bit
CLEN 0 1 Description 32KHz clock output enabled 32KHz clock output disabled Operation Default
Low Power Real-Time Clock (RTC)
ACE5372
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 0 1 Description Periodic interrupt output=OFF Periodic interrupt output=ON Operation Default
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 theINTRA or theINTRB to OFF ("H"). When this bit is set to "1" nothing happens.
AAFG, BAFG ALARM-A, ALARM-B Flag Bit
ALARM-AALARM-B 0 1
sensed for each alarm. * The AAFG, BAFG bit may be set only to "0". Setting this bit to "0" sets either the INTRA or the INTRB to the OFF "H". When this bit is set to "1" nothing happens.
Description Unmatched alarm register with clock counter Matched alarm register with clock counter
Operation Default
* The alarm interruption is enabled only when the AALE, BALE bits are set to "1". This bit turns to "1" when matched time is
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 AAFGBAFGBit and INTRAINTRB
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Technology Transmission System of Interface
Low Power Real-Time Clock (RTC)
ACE5372
Communication protocol determines: circuits in the equipment which sends data through SDA bus are regarded as emitters, contrarily, circuits in the equipment which receives 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. Changing 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
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
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 indicates 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 device type id. In ACE5372, 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 0 BIT6 1 BIT5 1 BIT4 0 BIT3 0 BIT2 1 BIT1 0 BIT0 R/W
BIT7-BIT1 : The slave 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 address 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 ACE5372 is specified at (0110010). At the 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 setting 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 S0110010 0 A Data A Data A P Slave address Write When data is read from the slave immediately after 7bit addressing from the master S 0 110010 1 A Data A Data A_ P Slave address Read
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
When the transmission direction is to be changed during transmission
Data Transmission Write Format in the ACE5372
A) First send 7 address bit(0110010), the eighth bit is write command "0". B) When the ninth bit is ACK signal, ACE5372 is under writing condition. C)In the following byte, the high 4 bits are determined as internal address in ACE5372(0H-FH), the low 4 bits are transmission model. D)After another bit's 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
Data Transmission Read Format in the ACE5372
The ACE5372 allows the following three readout methods of data 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 transmission in INTERFACE connection. C)Then send 7 address bit(0110010), the eighth bit command is "1", ACE5372 is under data reading condition. D) After another bit's ACK signal, it starts reading data normally.
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
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 reading operation be stopped and then CPU sends stop signals. Example 1 of data read (when data is read from 7H to 9H)
Inform ACE5372 to stop read
CPU to ACE5372
ACE5372 to CPU
Acknowledge signal
Start signal
Stop signal
Repeat Start signal
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 used. Example 2 of data read (when data is read from internal address Dh to 0h)
Inform ACE5372 to stop read
CPU to ACE5372 ACE5372 to CPU Acknowledge signal
Start signal
Stop signal
Repeat Start signal
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
III) 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).
CPU to ACE5372
ACE5372 to CPU
Acknowledge signal
Start signal
Stop signal
Repeat Start signal
Data Transmission Under Special Condition
The ACE5372 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 operation. When 0.5 to 1.0 seconds elapses after start condition any access to the ACE5372 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). Also 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 ACE5372 is automatically released. 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 while 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. ACE5372 confirms (Stop condition) and carry second digit being hold and the time changes to 10:00:00 PM. Then, when the hour digit is read, 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 frequency of CL (load capacitance) and available further grouped in several ranks as 1020 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 crystal oscillator.
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Technology Configuration of Oscillating Circuit
Low Power Real-Time Clock (RTC)
ACE5372
Because the adjustment of crystal oscillator frequency is also the adjustment of clock frequency, so the former adjustment can be done through CIN & COUT on the both sides of crystal. ACE5372 clock cooperates with CIN & COUT, so oscillator frequency can be referred to crystal CL. General, relation between CL and CIN or COUT is as follows
Cl =
Cin*Cout + Cs Cin+ Cout
CSBoard floating capacitance
If crystal oscillator frequency is on the higher side, the CL should be decreased, contrarily, the CL should be increased. According to this standard, the best CL is chosen to adjust frequency and clock frequency. For example: if the frequency is on the higher side, it can be lowed by attaching a CGOUT capacitor.
ACE5372
*CGOUT0~15pF
Time Trimming Circuit
Using the time trimming circuit gain or lose of clock may be adjusted with high precision by changing clock pulses for one second every 20 seconds. 1.When oscillation frequency *1 > target frequency*2clock gain Adjustment amount*3 =
(OscilationFrequency - T arg etFrequency + 0.1) OscillationFrequency * 2 (T arg etFrequency * 20)
= (Oscillation frequency - Target frequency) x 10 +1 *1) Oscillation frequency: Clock frequency output 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 (two's compliment).
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
2.When oscillation frequency = target frequency (no clock gain or loss) Set the adjustment value to 0 or +1, or -64, or -63 to disable adjustment. 3.When oscillation frequency < target frequency (clock losses) Adjustment amount =
(OscilationFrequency - T arg etFrequency ) OscillationFrequency * 2 (T arg etFrequency * 20)
= (Oscillation frequency - Target frequency) x 10
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 F6F5F4F3F2F1F0=0010101 2) When oscillation frequency =32762kHz; target frequency = 32768kHz Adjustment value =32762-32768/(32762*2/(32768*20)) = (32762-32768)*10=-60 To express -60 in 7bi binary digits with sign bit ( two's compliment) Subtract 60(3Ch) from 128(80h) in the above case, 80h-3Ch=44h Thus set F6F5F4F3F2F1F0=1000100 After adjustment, adjustment error against the target frequency will the approx. 1.5ppm at a room temperature.
Notice: 1) Clock frequency output from theINTRB 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 F6F5F4F3F2F1 F0 0000001 (0111111) and actual adjustable amount shall be -3.05ppm to -189.2ppm (-3.125ppm = to to 193.7ppm for 32000Hz crystal). B) When oscillation frequency is lower than target frequency, the range of adjustment values is F6F5F4F3F2F1 and actual adjustable amount shall be 3.05ppm to 189.2ppm (3.125ppm F0 1111111 1000010 = to to 193.7ppm for 32000Hz crystal)
Output Waveforms
The following three output waveforms can be output from the INTRA (INTRB) pin. 1Alarm interrupt When a registered time for alarm (such as day-of-the-week, hour or minute) 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. 2Periodic interrupt Outputs an output waveform selected by setting the periodic interrupt frequency select bit. Waveforms include pulse mode and level mode. 332KHz clock output Clock pulses generated in the oscillation circuit are output as they are.
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
Control of theINTRA (INTRB) Output (flag bit, enable bit, interrupt output select bit)
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 output wave form and the output select bit that selects either INTRA or INTRB to be output.
Interrupt output select bit SL2SL1 Flag bit AAFG (D1 at FH) BAFG (D0 at FH) CTFG (D2 at FH) NO Enable bit 00 Alarm_A Alarm_B Periodic interrupt 32KHz clock output AALE (D7 at EH) BALE (D6 at EH) Disabled at CT2=CT1=CT0=0 (D2 to D0 at EH) CLEN (D3 at FH) INTRA INTRA INTRA INTRB (D5D4 at EH) 01 INTRA INTRB INTRA INTRB 10 INTRA INTRA INTRB INTRB 11 INTRA INTRB INTRB INTRB
* 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.
When 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 AALEBALEbit to 0. After that set the AALEBALE bit to 1, from this moment onward when such registered alarm time coincide the value of calendar counter theINTRA (INTRB) comes down to "L" (ON). The INTRA (INTRB) output can be controlled by operating to the AALE (BALE) and AAFG (BAFG) bits.
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
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.
CT2 0 0 0 0 1 1 1 1 CT1 0 0 1 1 0 0 1 1 CT0 0 1 0 1 0 1 0 1 Description Wave Form Mode Pulse Mode Pulse Mode Level Mode Level Mode Level Mode Level Mode Cycle and INTRA(INTRB) Falling Timing INTRAINTRBOFF (Default) INTRAINTRBfixed at "L" 2Hz (Duty 50%) 1Hz (Duty 50%) Every second (coincident with second count-up) Every minute (00 second of every minute) Every hour (00minute 00second of every hour) Every month (1st day, 00:00:00 a.m.of every month)
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 range 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.
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
Level mode: Frequency in 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
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 monitoring 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". *1The XSTP bit is set to "1" upon power-on from 0V. Note that any instantaneous power disconnection may cause operation failure. *2Once oscillation halt has been sensed, the XSTP bit is held at "1" even if oscillation is restarted. Ensure error-free oscillation 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 individual pins of the IC
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Technology DC Characteristics
TOPT=-40 to +85, GND=0V, VDD=3.6V, fOSC=32,768Hz or 32,000Hz Symbol VIH VIL IOL1 IOL2 IILK VDD IOZ Item "H" Input Voltage "L" Input Voltage "L" Output Current Input Leakage Current Operating Voltage Counting Voltage Output Off State Leakage Current Pin name SCL, SDA SCL, SDA INTRA, INTRB SDA SCL VDD GND SDA, INTRA, INTRB VDD
Low Power Real-Time Clock (RTC)
ACE5372
Conditions
Min. 0.8VDD -0.3
Typ.
Max. 6.0 0.3VDD
Unit V V mA mA
VOL1=0.4V VOL2=0.6V VI=6VorGND VDD=6V
1 7 -1 1.8 1.2 1 5.5 5.5 1
uA V V uA
VO=6VorGND VDD=6V VDD=5V, TOPT=25 SCL,SDA=5V
-1
IDD
Standby Current
0.4
uA
AC Characteristics
Characteristics Parameter
TA= -40 to +85VDD =4.5V to 5.5V Symbol fSCL tLOW tHIGH tBUF tSU:STA tSU:STO tHD:STA tHD:STO tSU:DAT tHD:DAT THD tAA tR tF tI Item SCL Clock Frequency SCL Clock "L" Time SCL Clock "H" Time Bus release Time Start Condition Setup Time Stop Condition Setup Time Start Condition Hold Time Stop Condition Hold Time Data Setup Time Data input Hold Time Data output Hold Time clock output Rising Time of SCL and SDA (Input) Falling Time of SCL and SDA (Input) Spike width that can be removed with input filter SCL negedge to SDA data changes SCL negedge to SDA data availed before next data is transmitted Conditions Min. 0 4.7 5 4.7 4.7 4.7 4 4 250 0 0 0.3 3.5 1 300 100 Max. 100 Unit KHz us us us us us us us ns ns ns us us ns ns
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
Absolute Maximum Ratings
Symbol VDD VI VO1 VO2 TOPT TSTG Item Supply Voltage Input Voltage Output Voltage 1 Output Voltage 2 Operating Temperature Storage Temperature SCLSDA SDA INTRA, INTRB Conditions Ratings -0.3 to +7.0 -0.3 to +7.0 -0.3 to +7.0 -0.3 to +12.0 -40 to +85 -55 to +125 Unit V V V V
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Technology Typical Applications
Example of Circuit
Low Power Real-Time Clock (RTC)
ACE5372
ACE5372
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 VCC's Voltage: VBATTVVCC 4.Connect the pull-up resistor of the INTRA pin or the INTRB pin to two different positions depending battery back-up: A. when the spare battery supplies power, INTRA (B) is not used. B. when the spare battery supplies power, INTRA (B) is used.
Example of Interface Circuit to the CPU
ACE5372
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Technology Package Information
SOP-8
Low Power Real-Time Clock (RTC)
ACE5372
Symbol A A1 B C D ddd E e H h L
mm Min 1.35 0.10 0.33 0.19 4.80 3.80 5.80 0.25 0.40 0
o
Inches Max 1.75 0.25 0.51 0.25 5.00 0.10 4.00 6.20 0.50 0.90 8
o
Typ. 1.27 -
Min 0.053 0.004 0.013 0.007 0.189 0.150 0.228 0.010 0.016 0
o
Typ. 0.050 -
Max 0.069 0.010 0.020 0.010 0.197 0.004 0.157 0.244 0.020 0.035 8o
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Technology
Tssop-8
Low Power Real-Time Clock (RTC)
ACE5372
Dimensions (mm are the original dimensions) Unit mm Unit mm
Notes 1.Plastic 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
A max. 1.10
A1
A2
A3
Bp
C
D(1)
E(2)
e
0.32 0.25 3.10 4.60 0.15 0.95 0.65 0.25 0.12 0.10 2.90 4.20 0.05 0.80
HE L Lp v w y Z(1) 0.70 100 0.80 6.70 0.1 0.1 0.1 0.94 0.35 00 0.20 6.10
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Technology
Low Power Real-Time Clock (RTC)
ACE5372
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 sued 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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