Real-Time Clock. CDP1879C-1 Datasheet

CDP1879C-1 Clock. Datasheet pdf. Equivalent


GE CDP1879C-1
CMOS Peripherals
CDP1879, CDP1879C-1
iN'f
RESET
POWER DOWN
iii)
X-O/MEM
TPB/Wii
TPA
CS
A2
AI
AD
VSS'
I
2
5
4
5
6
7
B
9
10
II
12
24 VDD
23 XTAL
22 XTAL
21
CLOCK
OUT
20 DB7
19 DBS
IB DBS
17 OB4
16 OB3
15 OB2
14 OBl
15 OBO
92CS-54345RI
TERMINAL ASSIGNMENT
CMOS Real-Time Clock
Features
• CPU interface for use with general-purpose microprocessors
• Time of day/calendar
• Reads seconds, minutes, hours
• Reads day of month and month
• Alarm circuit with seconds, minutes or hours operation
• Power down mode
• Separate clock output selects 1 of 15 square wave signals
• Interrupt output activated by clock output and/or alarm circuit
• Data integrity sampling for clock rollover eliminated
• On-board oscillator 4.19 MHz, 2.09 MHz or 1.048 MHz
@ 10 V (CDP1879) crystal operation
4.19 MHz, 2.09 MHz, 1.048 MHz or 32 kHz @ 5 V
(CDP1879C-1) crystal operation
4.19 MHz, 2.09 MHz, 1.048 MHz or 32 kHz
@ 10 V or 5 V external clock operation
• Addressable in memory space or CDP1800 series I/O mode
• Low standby (timekeeping) voltage with external clock
The CDP1879 real-time clock supplies time and calendar
information from seconds to months in BCD format. It
consists of 5 separately addressable and programmable
counters that divide down an oscillator input. The clock
input can have anyone of 4 possible frequencies, allowing
flexibility in the choice of crystal or external clock sources.
Using an external 32-kHz clock source, timekeeping can be
performed down to 2.5 V (see Standby (Timekeeping)
Voltage Operation).
The device can be memory-mapped for use with any
general-purpose microprocessor and has the additional
capability of operating in the CDP1800-series input/output
mode.
The real-time clock functions as a time-of-day/calendar
with an alarm capability that can be set for combinations of
seconds, minutes or hours. Alarm time is configured by
loading alarm latches that activate an interrupt output
through a comparator when the counter and alarm latch
values are equal.
CDP1879 MODES OF OPERATION
OPERATION
FUNCTION
Fifteen selectable square-wave signals are available as a
separate clock output signal and can also activate the
interrupt output. A status register is available to indicate the
interrupt source. The value in an 8-bit control register
determines the operational characteristics of the device, by
selecting the prescaler divisor and the clock output, and
controls the load and alarm functions.
A transparent "freeze" circuit precludes clock rollover
during counter and latch access times to assure stable and
accurate values in the counters and alarm latches.
The CDP1879 is functionally identical to the CDP1879C-l.
The CDP1879 has a recommended operating voltage range
of 4 to 10.5 volts, and the CDP1879C-1 has a recommended
operating voltage range of 4 to 6.5 volts. The CDP1879 and
the CDP1879C-1 are supplied in 24-lead hermetic dual-in-
line side-brazed ceramic packages (0 suffix) and 24-lead
dual-in-line plastic packages (E suffix).
Read
1. Seconds, minutes, hours, date and month counters
2. Status register to identify interrupt source
Write
Power Down
Interrupt
1. Control register to set device operation
2. Seconds, minutes, hours, date and month counters
3. Alarm latches for alarm time
1. Tri-state interrupt output with active alarm or clock out circuitry for wake-up
control.
2. Data bus and address inputs are "DON'T CARE".
1. Clock out as source
2. Alarm time as source
3. Either ·interrupt can occur during normal or power down· mode
File Number 1360
452 ______________________________________________________________


CDP1879C-1 Datasheet
Recommendation CDP1879C-1 Datasheet
Part CDP1879C-1
Description CMOS Real-Time Clock
Feature CDP1879C-1; CMOS Peripherals CDP1879, CDP1879C-1 iN'f RESET POWER DOWN iii) X-O/MEM TPB/Wii TPA CS A2 AI AD VS.
Manufacture GE
Datasheet
Download CDP1879C-1 Datasheet




GE CDP1879C-1
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ CMOS Peripherals
CDP1879, CDP1879C·1
MAXIMUM RATINGS, Absolute-Maximum Values:
DC SUPPLY-VOLTAGE RANGE, (Vee)
(Vollage referenced 10 Vss Terminal)
CDP1879 ...........................................................................................................-0.5 10 +11 V
CDPI879C-l ........................................................................................................ -0.510 +7 V
INPUT VOLTAGE RANGE, ALL INPUTS .......................................................................... -0.510 Vee +05 V
DC INPUT CURRENT, ANY ONE INPUT ................................................................................... ±10 mA
POWER DISSIPATION PER PACKAGE (Pe)
For TA = -4010 +60· C (PACKAGE TYPE E) ............................................................................... 500 mW
For TA = +6010 +85·C (PACKAGE TYPE E) ................................................. Derale Linearly al12 mW/·C 10 200 mW
For TA = -5510 +100· C (PACKAGE TYPE D) ........•...............................•..................................... 500 mW
ForTA = +100 10 +125·C (PACKAGE TYPE D) .............................................. Derale Linearly al12 mW/·C 10 200 mW
DEVICE DISSIPATION PER OUTPUT TRANSISTOR
For TA = FULL PACKAGE-TEMPERATURE RANGE (All Package Types) .................................................... 40 mW
OPERATING-TEMPERATURE RANGE (TA):
PACKAGE TYPE D, H ............................................................................................. -5510 +125·C
PACKAGE TYPE E ....................................................................................... . ..... -40 10 +85· C
STORAGE TEMPERATURE RANGE (TO'9) ........................................................................... -6510 +150·C
LEAD TEMPERATURE (DURING SOLDERING)
AI dislance 1/16 ± 1/32 in (1.59 ± 0 79 mm) from case for 10 s max ..................................................... +265·C
OPERATING CONDITIONS at TA=Full Package-Temperature Range, unle•• otherwise noted.
For maximum reliability, operating condition. Ihould be selected 10 that operation II alwaYI within the following rangel:
CHARACTERISTIC
DC Operating Voltage Range
Input Voltage Range
DC Standby (Timekeeping) Voltage"
TA = -40° to +85° ct
TA = 0° to +70°C
Clock Input Rise or Fall Time
Voo = 5 V
Voo= 10V
Vs,.v
t"t,
LIMITS
CDP1879
CDP1879C-l
Min.
Max.
Min.
Max.
4 10.5 4
6.5
Vss Voo
Vss Voo
3-
2.5 -
3-
2.5 -
- 10 - 10
-
1-
-
"Timekeeping funclion only, no READ/WRITE accesses, 32-kHz exlernal frequency source only,
no cryslal operation.
tSee Standby (Timekeeping) Voltage Operalion, Page ".
UNITS
V
V
ps
___________________________________________ 453



GE CDP1879C-1
CMOS Peripherals
CDP1879, CDP1879C-1
A2
TPA
I-O/MEM
TPB/W""A"
ADDRESS DECODE
AND
CONTROL LOGIC
-
CS
POWER DOWN
TABLE I
Control Register Bit Assignment
Bit 1, 0
Fig. 1 - Real-tIme clock functional diagram.
TABLE II
Addresses
A2 A1 AO
Frequency 00
Select 01
10
11
32768 Hz
1.048576 MHz
2.097152 MHz
4.194304 MHz
Blt2
Start/Stop
1 = Start
o = Stop
Blt3
Counter/Latch Control
"0" = Write to counter and
disable alarm
"1" = Write to &enable alarm
Clock Select
Bits 7, 6, 5, 4
0000 - disable J1S
1000 - 62.5 ms
0001 - 488.2 J1S
1001 - 125 ms
0010 - 976.5 J1S
1010 - 250 ms
0011 - 1953.1 J1S
1011 - 500 ms
0100 - 3906.2 J1S
1100 - sec.
0101 - 7812.5 J1S
1101 - min.
0110 - 15.625 ms
1110 - hour
0111 - 31.25 ms
1111 - day
Latch, Counter Seconds
Latch, Counter Minutes
Latch, Counter Hours
Counter, Day
Counter, Month
Control, Register
Status Register
0 10
011
100
101
1 10
111
111
MSB of hours counters (Bit 7) is an AM-PM bit. 0 = AM;
1 = PM.
Bit 6 of hours counter controls 12/24 hr. 1 = 12 hr:
0= 24 hr.
Status Register: Bit 7 MSB = alarm
Interrupt Source: Bit 6 = clock
MSB of Month Counter (Bit 7) is a Leap Year Bit 0 = No,
1 = Yes.
454 _________________________________________________________________







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