R
EM MICROELECTRONIC-MARIN SA
A3024
Very Low Power 8-Bit 32 kHz RTC with
Digital Trimming, User RAM and High Level Integration
Features
n
Digital trimming and temperature compensation
facilities
n
Can be synchronized to 50 Hz or nearest s/min
n
50 ns access time with 50 pF load capacitance
n
Standby on power down typically 1.2
m
A
n
Universal interface compatible with both Intel and Motorola
n
Simple 8 bit interface with no delays or busy flags
n
16 bytes of user RAM
n
Power fail input disables during power up / down or reset
n
Bus can be tri-state in power fail mode
n
Wide voltage range, 2.0 V to 5.5 V
n
12 or 24 hour data formats
n
Time to 1/100 of a second
n
Leap year correction and week number calculation
n
Alarm and timer interrupts
n
Programmable interrupts: 10 ms, 100 ms, s or min
n
Sleep mode capability
n
Alarm programmable up to one month
n
Timer measures elapsed time up to 24 hours
n
Temperature range -40 to +85
O
C
n
Packages DIP20 and SO20
Typical Operating Configuration
WR or R/W
RD or DS
IRQ
CPU
Address
Decoder
Description
The A3024 is a low power CMOS real time clock. Standby
current is typically 1.2
m
A and the access time is 50 ns. The
interface is 8 bits with multiplexed address and data bus.
Multiplexing of address and data is handled by the input line
A/D. There are no busy flags in the A3024, internal time update
cycles are invisible to the user’s software. Time data can be
read from the A3024 in 12 or 24 hour data formats. An external
signal puts the A3024 in standby mode. Even in standby, the
A3024 pulls the IRQ pin active low on an internal alarm interrupt.
Calendar functions include leap year correction and week
number calculation. Time precision can be achieved by digital
triming. The A3024 can be synchronized to an external 50 Hz
signal or to the nearest second or minute.
CS
RD
WR
Address Bus
CS
IRQ
RD
X in
WR
A3024
A/D
X out
AD0 to AD7
Data Bus
RAM
Fig. 1
Pin Assignment
DIP20 / SO20
Applications
n
n
n
n
n
Industrial controllers
Alarm systems with periodic wake up
PABX and telephone systems
Point of sale terminals
Automotive electronics
SYNC
PF
AD0
AD1
AD2
AD3
A/D
IRQ
V
SS
X
IN
A3024
NC
AD7
AD6
AD5
AD4
RD
WR
CS
V
DD
X
OUT
Fig. 2
1
EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
