pcf8593 NXP Semiconductors, pcf8593 Datasheet - Page 12

• Manufacturer Part Number: pcf8593
• Description: Low Power Clock/calendar
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.9
The conditions for activating the open-drain n-channel
interrupt output INT (active LOW) are determined by
appropriate programming of the alarm control register.
These conditions are clock alarm, timer alarm, timer
overflow, and event counter alarm. An interrupt occurs
when the alarm flag or the timer flag is set, and the
corresponding interrupt is enabled. In all events, the
interrupt is cleared only by software resetting of the flag
which initiated the interrupt.
1997 Mar 25
handbook, full pagewidth
Low power clock/calendar
Interrupt output
MSB
7
MBD817
Fig.10 Alarm control register, event-counter mode.
6
5
4
3
2
12
In the clock mode, if the alarm enable is not activated
(alarm enable bit of control/status register is logic 0), the
interrupt output toggles at 1 Hz with a 50% duty cycle (may
be used for calibration). The OFF voltage of the interrupt
output may exceed the supply voltage, up to a maximum
of 6.0 V. A logic diagram of the interrupt output is shown in
Fig.11.
1
LSB
0
memory location 08
timer function :
000
001
010
011
100
101
110
111
timer interrupt enable :
0
1
clock alarm function :
00
01
10
11not allowed
timer alarm enable :
0
1
alarm interrupt enable :
0
1
not allowed
no timer
units
100
10 000
1 000 000
not allowed
test mode, all counters
in parallel
timer flag, no interrupt
timer flag, interrupt
no event alarm
event alarm
not allowed
no timer alarm
timer alarm
alarm flag, no interrupt
alarm flag, interrupt
Product specification
PCF8593