Motorola MVME172 - Manual (Page 148)

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VMEchip2
2
Tick Timer 2 Compare Register
The tick timer 2 counter is compared to this register. When they are equal,
an interrupt is sent to the local bus interrupter and the overflow counter is
incremented. If the clear-on-compare mode is enabled, the counter is also
cleared. For periodic interrupts, the following equation should be used to
determine the compare register value for a specific period.
compare register value = T (
µ
s)
When programming the tick timer for periodic interrupts, the counter
should be cleared to zero by software and then enabled. If the counter does
not initially start at zero, the time to the first interrupt may be longer or
shorter than expected. Remember the rollover time for the counter is 71.6
minutes.
Tick Timer 2 Counter
This is the tick timer 2 counter. When enabled, it increments every
microsecond. Software may read or write the counter at any time.
ADR/SIZ $FFF40058 (32 bits)
BIT 31 . . . 0
NAME Tick timer 2 Compare Register
OPER R/W
RESET 0 P
ADR/SIZ $FFF4005C (32 bits)
BIT 31 . . . 0
NAME Tick timer 2 Counter
OPER R/W
RESET 0 P