NO:
W90P710 Programming Guide
VERSION:
2.0
PAGE:
183
The above information is the exclusive intellectual property of Winbond Electronics and shall not be disclosed, distributed or reproduced without permission
from Winbond.
Table No.: 2005-W90P710-11-A
RTC_DWR
0xFFF8.4018 R/W
Day of the Week Register
0x0000.0006
RTC_TAR 0xFFF8.401C
R/W
Time
Alarm
Register
0x0000.0000
RTC_CAR 0xFFF8.4020
R/W
Calendar
Alarm
Register
0x0000.0000
RTC_LIR
0xFFF8.4024
R
Leap year Indicator Register
0x0000.0000
RTC_RIER
0xFFF8.4028 R/W
RTC Interrupt Enable Register
0x0000.0000
RTC_RIIR
0xFFF8.402C R/C
RTC Interrupt Indicator Register
0x0000.0000
RTC_TTR
0xFFF8.4030 R/W
RTC Time Tick Register
0x0000.0000
15.4 Functional Description
15.4.1 Initialization
When RTC block is power on, programmer has to write a number Oxa5eb1357 to register
INIR
to
reset all logic.
INIR
act as hardware reset circuit. Once
INIR
has been set as 0xa5eb1357, user
cannot reload any other value.
15.4.2 RTC
Read/Write
Enable
Register
AER
bit 15~0 is RTC read /write password. It is used to avoid signal interference from
system during system power off.
AER
bit 15~0 has to be set as
0xa965
after system power on, and be
set as 0x0000 before system power off. Once it is set, it will take effect 10 RTC clocks later(about
300us). Programmer can read
AER
bit 16 to find out whether RTC register can be accessed.
15.4.3 Frequency
Compensation
The RTC
FCR
allows software control digital compensation of a 32.768Khz crystal oscillator.
User can utilize a frequency counter to measure RTC clock in one of GPIO pin during manufacture,
and store the value in Flash memory for retrieval when the product is first power on.