SIS Documentation
SIS3800
Scaler/Counter
Page 26 of 39
17 Test
The SIS380x scaler series provides the user with a number of test features, which allow for
debugging of the unit as well as for overall system setups.
17.1 LED (selftest)
During power up self test and LCA configuration all LEDs except the Ready (R) LED are on.
After the initialisation phase is completed, all LEDs except the Ready (R) LED and the Power
(P) have to go off. Differing behaviour indicates either a problem with the download of the
firmware boot file or one or more LCA and/or the download logic.
17.2 Internal pulser tests
17.2.1 Single Pulse
A single pulse into all channels can be generated with a write to the key address 0x68 if test
mode is enabled via the control register. In conjunction with the count enable register more
complex count patterns, like increment patterns e.g., can be generated before readout.
17.2.2 25 MHz Pulser
Simultaneous pulsing at 25 MHz into all channels can be used to test the complete readout
chain and internal counter logic of the SIS3800. The feature is activated by enabling input test
mode and 25 MHz test pulses via the corresponding bits in the control register.
The 25 MHz test pulser gives easy access to your VME CPUs readout timing. By making
subsequent reads to the same counter and multiplying the difference in counts with 40 ns you
can measure the single word access time.
17.3 Reference pulser channel 1
The reference pulser for channel 1 can be seen rather as a monitoring feature than a test
feature. It sets the counting rate of channel 1 to 25 MHz (note, that a simultaneous front panel
signal on channel 1 is ignored).
17.4 Signal-Input Priority
If the user happens to enable more than one input option (enable test mode, enable reference
pulser, scaler enable) at the same time, the priority is as show in the table below:
Priority
Feature
1
Test mode
2
Reference Pulser (channel 1 only)
3
Front Panel Inputs
Example: If test mode and reference pulser are enabled at the same time, channel one will
count test pulses (i.e. will count synchronous with the test pulser).
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
