SIS Documentation
SIS3820
VME Scaler
Page 20 of 79
7.1.1 Counter test mode
VME Key test pulse signals will be counted by all (non inhibited) counters in test mode.
Counter test mode has to be activated for 25 MHz test pulse operation also.
7.1.2 25 MHz test pulse mode
All (non inhibited) scaler channels will count 25 MHz test pulses if this bit and the counter
test mode bit is set. From firmware 01 0A on you can use the test pulse mask register to
exclude selected channels from participating in test pulse counting.
7.1.3 Reference pulser channel 1
Channel 1 will count 50 MHz reference pulses (precision defined by the on board 100 ppm 50
MHz quarz) if this bit is set.
Note:
test mode has priority over reference pulser, i.e. reference pulses will not be counted if
test mode (with or without 25 MHz test pulse mode) is active.