www.geehy.com Page 291
Field
Name
R/W
Description
15:0
SUBSEC
R
Sub Second Value Setup
When a timestamp event occurs, SUBSEC [15:0] is the value in
synchronous prescaler counter.
31:16
Reserved
RTC precision calibration register (RTC_CAL)
This register is in write protection state.
Offset address: 0x3C
Reset value of backup domain: 0x0000 0000
System reset: 0xXXXX XXXX
Field
Name
R/W
Description
8:0
RECALF
R/W
Reduced Calibration Frequency
Reduced date frequency: Mask RECALF pulses within 2
20
RTCCLK
pulses (32sec if the output frequency is 32768 Hz) and the date
frequency will be reduced (the resolution is 0.9537 ppm).
Increased date frequency: It takes effect at the same time with
ICALFEN
12:9
Reserved
13
CAL16CFG R/W
16 Second Calibration Cycle Period Configure
When CAL16CFG is set to 1, 16-second calibration cycle is used, and
it cannot be set to 1 at the same time with CAL8CFG bit.
When CAL16CFG=1, RECALF [0] is always 0.
14
CAL8CFG
R/W
8 Second Calibration Cycle Period Configure
When CAL8CFG is set to 1, 8-second calibration cycle is used, and it
cannot be set to 1 at the same time with CAL16CFG bit.
When CAL8CFG=1, RECALF [1:0] is always 00.
15
ICALFEN
R/W
Increase Calibration Frequency Enable
0: RTCCLK pulse is not increased
1: One RTCCLK pulse is increased (the frequency increases by 488.5
ppm) every 2
11
pulses
It takes effect at the same time with RECALF, and when the resolution
is high, the date frequency will be reduced. If the input frequency is
32768Hz, the number of RTCCLK pulses added in the 32-second
window is determined by the following formula:
(512*ICALFEN)–RECALF
。
31:16
Reserved
RTC tamper and multiplexing configuration register
(RTC_TACFG)
Offset address: 0x40
Reset value of backup domain: 0x0000 0000
System reset: 0xXXXX XXXX
Field
Name
R/W
Description
0
TP1EN
R/W
RTC_TAMP1 Input Detection Enable
0: Disable