w83977f Winbond Electronics Corp America, w83977f Datasheet - Page 110

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

6.3.2 Register 0Bh (Read/Write)
SET
When the SET bit is set, any occurring update cycle is aborted and registers (Register 00h~09h,
Register (40h~48h) may be modified without entering an update cycle. When this bit is cleared, the
update cycle function occurs once per second. This bit is not affected by any other internal functions
or by a RESET.
PE
A "1" on the periodic interrupt enable bit enables the periodic interrupt flag (PF) bit in Register 0Ch to
A "0" on this bit blocks the IRQ output from being driven by a periodic interrupt. This bit can not be
AE
A "1" on the enable bit of alarm A enables the alarm A flag (AF) bit in Register 0Ch to assert an
A "0" on this bit prohibits alarm A interrupt. The RESET signal clears AE to "0". This bit can not be
UE
A "1" on this bit enables the update-ended flag (UF) bit in register C to assert an interrupt.
A "0" on this bit prohibits update-ended interrupt. The UE bit is cleared by setting the SET bit or by a
DM
The data mode bit determines whether time and calendar updates are in binary format or in binary-
coded-decimal (BCD) format.
A "1" on this bit means binary format.
A "0" on this bit means BCD format. This bit can not be modified by a RESET or any internal
function.
24/12
A "1" on this bit selects 24-hour mode for the time-of-day function.
A "0" on this bit selects 12-hour mode. This bit can not be modified by a RESET or any internal
DSE
A "1" on this bit allows two special updates:
A "0" on this bit disables these special updates. DSE can not be changed by any internal operation or
(Note: RTC IRQ is ultimately controlled by Logical Device 4-CR70 and Logical Device 4-CR71. These two registers must be set
NAME
assert an interrupt.
modified by any internal function, but it may be cleared by a RESET.
interrupt.
modified by any internal function.
RESET.
function.
BIT
a RESET.
properly if RTC IRQ is needed)
On the last Sunday of April, the time increments from 1:59:59 AM to 3:00:00 AM.
On the last Sunday of October, the time decrements from 1:59:59 AM to 1:00:00 AM.
SET
7
PE
6
AE
5
- 98 -
UE
4
Reserved
3
W83977F/ W83977AF
Publication Release Date: January 1997
DM
2
12/24
PRELIMINARY
1
Revision 0.50
DSE
0