82NM10 Datasheet, PDF (399/671 Pages) Intel Corporation – Intel® NM10 Family Express Chipset

LPC Interface Bridge Registers (D31:F0)
13.6.2.2
Bit
Description
3:0 Rate Select (RS[3:0]) — R/W. Selects one of 13 taps of the 15 stage divider chain.
The selected tap can generate a periodic interrupt if the PIE bit is set in Register B.
Otherwise this tap will set the PF flag of Register C. If the periodic interrupt is not to be
used, these bits should all be set to 0. RS3 corresponds to bit 3.
0000 = Interrupt does not toggle
0001 = 3.90625 ms
0010 = 7.8125 ms
0011 = 122.070 µs
0100 = 244.141 µs
0101 = 488.281 µs
0110 = 976.5625 µs
0111 = 1.953125 ms
1000 = 3.90625 ms
1001 = 7.8125 ms
1010 = 15.625 ms
1011 = 31.25 ms
1100 = 62.5 ms
1101 = 125 ms
1110 = 250 ms
1111= 500 ms
RTC_REGB—Register B (General Configuration)
(LPC I/F—D31:F0)
RTC Index:
Default Value:
Lockable:
0Bh
Attribute:
U0U00UUU (U: Undefined) Size:
No
Power Well:
R/W
8-bit
RTC
Bit
Description
7 Update Cycle Inhibit (SET) — R/W. Enables/Inhibits the update cycles. This bit is not
affected by RSMRST# nor any other reset signal.
0 = Update cycle occurs normally once each second.
1 = A current update cycle will abort and subsequent update cycles will not occur until
SET is returned to 0. When set is one, the BIOS may initialize time and calendar
bytes safely.
NOTE: This bit should be set then cleared early in BIOS POST after each powerup
directly after coin-cell battery insertion.
6 Periodic Interrupt Enable (PIE) — R/W. This bit is cleared by RSMRST#, but not on
any other reset.
0 = Disable.
1 = Enable. Allows an interrupt to occur with a time base set with the RS bits of register
A.
5 Alarm Interrupt Enable (AIE) — R/W. This bit is cleared by RTCRST#, but not on any
other reset.
0 = Disable.
1 = Enable. Allows an interrupt to occur when the AF is set by an alarm match from the
update cycle. An alarm can occur once a second, one an hour, once a day, or one a
month.
Datasheet
399