Rtc Control Register (Rtc_Ctrl_Reg) - Texas Instruments OMAP5910 Technical Reference Manual

Real-Time Clock
Table 7–139. RTC Control Register (RTC_CTRL_REG)
Bit Name
7 Reserved
6 RTC_DISABLE
5 SET_32_COUNTER
4 TEST_MODE
3 MODE_12_24
2 AUTO_COMP
1 ROUND_30S
0 STOP_RTC
† RTC_DISABLE can be written to 1 to disable RTC clock. Behavior is unpredictable if this bit is reset to 0 after having been
set to 1.
‡ SET_32_COUNTER must only be used when the RTC is frozen. The set operation is asynchronous, which means the RTC
counter is frozen to the compensation value as long as this bit is set. The correct sequence: reset STOP_RTC (freezes RTC),
set SET_32_COUNTER bit, set STOP_RTC (launches RTC), then reset SET_32_COUNTER bit (3 register writes).
§ You can switch between the two modes at any time without disturbing the RTC. Read or write is always performed using the
current mode.
¶ ROUND_30S is a toggle bit: MPU can only write 1, RTC clears it. If the MPU sets this bit and then reads it, the MPU reads
1 until the rounding to the closet minute is performed at the next second.
7-182
Reset
Function
Value
†
0 RTC enabled
1 RTC disabled (no 32-kHz clock)
‡
0 No action
1 Sets the 32-kHz counter with COMP_REG (14:0) val-
ue
0 Functional mode
1 Test mode (autocompensation is enabled when
32-kHz counter reaches its end)
§
0 24-hour mode
1 12-hour mode (PM/AM mode)
0 Autocompensation disabled
1 Autocompensation enabled
¶
0 No update
1 Rounding enabled
0 RTC is frozen
1 RTC is running
R/W
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W