MVME3100 Programmer’s Guide (V3100A/PG1)
Chapter 1 Board Description and Memory Maps
22
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. The rollover time for the counter is 71.6 minutes.
Counter Registers
When enabled, the tick timer Counter register increments every microsecond. Software may read or
write the counter at any time.
Geographical Address Register
The VMEbus Status register in the TSi148 provides the VMEbus geographical address of the
MVME3100. This register reflects the inverted states of the geographical address pins at the 5-row, 160-
pin P1 connector.
Table 1-21. Tick Timer Compare Registers
REG
Tick Timer 1 Compare Register - 0xE202 0014 (32 bits)
Tick Timer 2 Compare Register - 0xE202 0024 (32 bits)
Tick Timer 3 Compare Register - 0xE202 0034 (32 bits)
Tick Timer 4 Compare Register - 0xE202 0044 (32 bits)
BIT
31
0
FIELD
Tick Timer Compare Value
OPER
R/W
RESET
0
Table 1-22. Tick Timer Counter Registers
REG
Tick Timer 1 Counter Register - 0xE202 0018 (32 bits)
Tick Timer 2 Counter Register - 0xE202 0028 (32 bits)
Tick Timer 3 Counter Register - 0xE202 0038 (32 bits)
Tick Timer 4 Counter Register - 0xE202 0048 (32 bits
BIT
31
0
FIELD
Tick Timer Counter Value
OPER
R/W
RESET
0