DS17285E3 MAXIM [Maxim Integrated Products], DS17285E3 Datasheet - Page 8

• Manufacturer Part Number: DS17285E3
• Description: Real-Time Clocks
• Manufacturer: MAXIM [Maxim Integrated Products]

Real-Time Clocks
8
24
13
14
15
17
18
19
20
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PIN
28
23
24
25
27
28
1
2
NAME
V
ALE
IRQ
WR
CS
RD
KS
BAT
Active-Low Chip-Select Input. This pin must be asserted low during a bus cycle for the device
to be accessed. CS must be kept in the active state during RD and WR. Bus cycles that take
place without asserting CS latch addresses, but no access occurs.
Address Latch Enable Input, Active High. This input pin is used to demultiplex the
address/data bus. The falling edge of ALE causes the address to be latched within the device.
Active-Low Write Input. This pin defines the period during which data is written to the
addressed register.
Active-Low Read Input. This pin identifies the period when the device drives the bus with read
data. It is an enable signal for the output buffers of the device.
Active-Low Kickstart Input. When V
powered on in response to an active-low transition on the KS pin, as might be generated from
a key closure. V
the kickstart function is used, and the KS pin must be pulled up to the V
V
grounded and ABE set to 0.
Active-Low Interrupt Request. This pin is an active-low output that can be used as an interrupt
input to a processor. The IRQ output remains low as long as the status bit causing the interrupt
is present and the corresponding interrupt-enable bit is set. To clear the IRQ pin, the
application software must clear all enabled flag bits contributing to the pin’s active state. When
no interrupt conditions are present, the IRQ level is in the high-impedance state. Multiple
interrupting devices can be connected to an IRQ bus, provided that they are all open drain.
The IRQ pin requires an external pullup resistor to V
Connection for Primary Battery. This supply input is used to power the normal clock functions
when V
proper operation. If V
against reverse charging current when used with a lithium battery (
ic.com/qa/info/ul
CC
is applied, the KS pin can be used as an interrupt input. If not used, KS must be
CC
is absent. Diodes placed in series between V
BAUX
). This pin is missing (N.C.) on the EDIP package.
BAT
must be present and auxiliary-battery-enable bit (ABE) must be set to 1 if
is not required, the pin must be grounded. UL recognized to ensure
CC
is removed from the device, the system can be
FUNCTION
Pin Description (continued)
CC
.
BAT
and the battery can prevent
www.maxim-
BAUX
supply. While