2

VMEchip2

Tick Timer 1 Compare Register

ADR/SIZ

 

$FFF40050 (32 bits)

 

 

 

 

 

BIT

31

. . .

0

 

 

 

 

NAME

 

Tick timer 1 Compare Register

 

 

 

 

 

OPER

 

R/W

 

 

 

 

 

RESET

 

0 P

 

 

 

 

 

The tick timer 1 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 calculate the compare register value for a specific period (T).

compare register value = T (μs)

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 0, 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 1 Counter

ADR/SIZ

 

$FFF40054 (32 bits)

 

 

 

 

 

BIT

31

. . .

0

 

 

 

 

NAME

 

Tick timer 1 Counter

 

 

 

 

 

OPER

 

R/W

 

 

 

 

 

RESET

 

0 P

 

 

 

 

 

This is the tick timer 1 counter. When enabled, it increments every microsecond. Software may read or write the counter at any time.

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Computer Group Literature Center Web Site

Page 158
Image 158
Motorola MVME1X7P manual Tick Timer 1 Compare Register, Tick Timer 1 Counter