Philips Semiconductors
Product specification
Low power clock/calendar
Table 1
Cycle length of the time counters, clock modes.
UNIT
Hundredths of a second
Seconds
Minutes
Hours (24 h)
Hours (12 h)
COUNTING CYCLE
00 to 99
00 to 59
00 to 59
00 to 23
12 AM
01 AM to 11 AM
12 PM
01 PM to 11 PM
Date
01 to 31
01 to 30
01 to 29
01 to 28
Months
Year
Weekdays
Timer
7.5
01 to 12
0 to 3
0 to 6
00 to 99
Alarm control register
CARRY TO NEXT UNIT
99 to 00
59 to 00
59 to 00
23 to 00
−
−
−
11 PM to 12 AM
31 to 01
30 to 01
29 to 01
28 to 01
12 to 01
−
6 to 0
no carry
−
−
−
−
−
−
−
−
PCF8593
CONTENTS OF THE
MONTH COUNTER
1, 3, 5, 7, 8, 10 and 12
4, 6, 9 and 11
2, year = 0
2, year = 1, 2 and 3
−
−
−
−
When the alarm enable bit of the control/status register is
set (address 00, bit 2) the alarm control register
(address 08) is activated. All alarm, timer, and interrupt
output functions are controlled by the contents of the alarm
control register (see Fig.8).
7.6
Alarm registers
An alarm signal is generated when the contents of the
alarm registers matches bit-by-bit the contents of the
involved counter registers. The year and weekday bits are
ignored in a dated alarm. A daily alarm ignores the month
and date bits. When a weekday alarm is selected, the
contents of the alarm weekday/month register will select
the weekdays on which an alarm is activated (see Fig.9).
Remark:
in the 12 h mode, bits 6 and 7 of the alarm hours
register must be the same as the hours counter.
All alarm registers are allocated with a constant address
offset of hexadecimal 08 to the corresponding counter
registers (see Fig.4,Register arrangement).
1997 Mar 25
9
PHILIPS [ NXP SEMICONDUCTORS ]
