82801FB Datasheet, PDF (718/786 Pages) Intel Corporation – Intel I/O Controller Hub 6 (ICH6) Family

High Precision Event Timer Registers
20.1.3
.
20.1.4
.
GINTR_STA—General Interrupt Status Register
Address Offset: 020h
Default Value: 0000000000000000h
Attribute:
Size:
R/W, R/WC
64 bits
Bit
Description
63:3 Reserved. These bits will return 0 when read.
2 Timer 2 Interrupt Active (T02_INT_STS) — R/W. Same functionality as Timer 0.
1 Timer 1 Interrupt Active (T01_INT_STS) — R/W. Same functionality as Timer 0.
Timer 0 Interrupt Active (T00_INT_STS) — R/WC. The functionality of this bit depends on whether
the edge or level-triggered mode is used for this timer. (default = 0)
If set to level-triggered mode:
This bit will be set by hardware if the corresponding timer interrupt is active. Once the bit is set, it can
be cleared by software writing a 1 to the same bit position. Writes of 0 to this bit will have no effect.
0
If set to edge-triggered mode:
This bit should be ignored by software. Software should always write 0 to this bit.
NOTE: Defaults to 0. In edge triggered mode, this bit will always read as 0 and writes will have no
effect.
MAIN_CNT—Main Counter Value Register
Address Offset: 0F0h
Default Value: N/A
Attribute:
Size:
R/W
64 bits
Bit
Description
Counter Value (COUNTER_VAL[63:0]) — R/W. Reads return the current value of the counter.
Writes load the new value to the counter.
NOTES:
1. Writes to this register should only be done while the counter is halted.
2. Reads to this register return the current value of the main counter.
63:0
3. 32-bit counters will always return 0 for the upper 32-bits of this register.
4. If 32-bit software attempts to read a 64-bit counter, it should first halt the counter. Since this
delays the interrupts for all of the timers, this should be done only if the consequences are
understood. It is strongly recommended that 32-bit software only operate the timer in 32-bit
mode.
5. Reads to this register are monotonic. No two consecutive reads return the same value. The
second of two reads always returns a larger value (unless the timer has rolled over to 0).
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Intel^® I/O Controller Hub 6 (ICH6) Family Datasheet