w83977f Winbond Electronics Corp America, w83977f Datasheet - Page 107

• Manufacturer Part Number: w83977f
• Description: Plug & Play 1.0a Compliant
• Manufacturer: Winbond Electronics Corp America

Time, Calendar, Alarm A, and Alarm B data Modes continued
6.2 Update Cycle
The RTC executes an update cycle once per second. It is in an update cycle when RTC updates the
contents of the clock and calendar registers. In the meantime, RTC also compares each alarm byte
with corresponding timer byte and generates an alarm flag if a match or a don't care condition (0C0h)
is present in the alarm register.
The update-in-progress bit (UIP) in register A pulses high once per second. The update cycle occurs
244 S after the UIP bit goes high. This bit is cleared and the update-ended flag (UF) is set in the end
of an update cycle.
Register 05h
Register 06h
Register 07h
Register 08h
Register 09h
Register 40h
Register 41h
Register 42h
Register 43h
Register 44h
Register 45h
Register 46h
Register 47h
Register 48h
REGISTER
LOCATION
Hours Alarm A
(12-Hour Mode)
(24-Hour Mode)
Day of Week
Date of Month
Month
Year
Century
Sec. Alarm B
Min. Alarm B
Hours Alarm B
(12-Hour Mode)
(24-Hour Mode)
Day of Week
Alarm B
Date of Month
Alarm B
Month Alarm B 01h-0Ch
Year Alarm B
Century Alarm
B
FUNCTION
01h-0Ch(AM)
81h-8Ch(PM)
00h-17h
01h-07h
01h-1Fh
01h-0Ch
00h-63h
00h-63h
00h-3Bh
00h-3Bh
01h-0Ch(AM)
81h-8Ch(PM)
00h-17h
01h-07h
01h-1Fh
00h-63h
00h-63h
BINARY
RANGE(DATA MODE)
- 95 -
01h-12h(AM)
81h-92h(PM)
00h-23h
01h-07h
01h-31h
01h-12h
00h-99h
00h-99h
00h-59h
00h-59h
01h-12h(AM)
81h-92h(PM)
00h-23h
01h-07h
01h-31h
01h-12h
00h-99h
00h-99h
BCD
W83977F/ W83977AF
Publication Release Date:March 1998
BINARY
1Eh
1Eh
08h
08h
02h
04h
07h
61h
13h
08h
08h
02h
04h
07h
61h
13h
EXAMPLE
PRELIMINARY
Revision 0.58
BCD
08h
08h
02h
04h
07h
97h
19h
30h
30h
08h
08h
02h
04h
07h
97h
19h