Trigger modes and appendant registers
External (TTL) trigger using multi purpose I/O connectors
(c) Spectrum GmbH
97
HIGH level TTL trigger
This trigger mode will generate an internal gate signal that can be
very good used together with a second trigger mode to gate the
trigger. If using this mode as a single trigger source the card will
detect a trigger event at the time when entering the high level (act-
ing like positive edge trigger) or if the trigger signal is already at
high level at the start it will immediately detect a trigger event.
The trigger input is continuously sampled with the selected sample
rate. The trigger event will be detected if the trigger input is at TTL
high level.
Negative TTL trigger
This mode is for detecting the falling edges of an external TTL sig-
nal. The board will trigger on the first falling edge that is detected
after starting the board. The next triggerevent will then be detect-
ed, if the actual recording/replay has finished and the board is
armed and waiting for a trigger again.
LOW level TTL trigger
This trigger mode will generate an internal gate signal that can be
very good used together with a second trigger mode to gate the
trigger. If using this mode as a single trigger source the card will
detect a trigger event at the time when entering the low level (acting
like negative edge trigger) or if the trigger signal is already at low
level at the start it will immediately detect a trigger event.
The trigger input is continuously sampled with the selected sample
rate. The trigger event will be detected if the trigger input is at TTL
low level.
Register
Value
Direction
Description
SPC_TRIG_EXT1_MODE
40511
read/write
Sets the trigger mode for multi purpose X0 trigger input.
SPC_TRIG_EXT2_MODE
40512
read/write
Sets the trigger mode for multi purpose X1 trigger input.
SPC_TM_HIGH
8h
Sets the trigger mode for external TTL trigger to detect HIGH levels.
Register
Value
Direction
Description
SPC_TRIG_EXT1_MODE
40511
read/write
Sets the trigger mode for multi purpose X0 trigger input.
SPC_TRIG_EXT2_MODE
40512
read/write
Sets the trigger mode for multi purpose X1 trigger input.
SPC_TM_NEG
2h
Sets the trigger mode for external TTL trigger to detect negative edges.
Register
Value
Direction
Description
SPC_TRIG_EXT1_MODE
40511
read/write
Sets the trigger mode for multi purpose X0 trigger input.
SPC_TRIG_EXT2_MODE
40512
read/write
Sets the trigger mode for multi purpose X1 trigger input.
SPC_TM_LOW
10h
Sets the trigger mode for external TTL trigger to detect LOW levels.
