External TTL trigger | Trigger modes and appendant registers |
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Positive and negative TTL trigger
This mode is for detecting the rising and falling edges of an ex- ternal TTL signal. The board will trigger on the first rising or falling edge that is detected after starting the board. The next triggere- vent will then be detected, if the actual recording/replay has fin- ished and the board is armed and waiting for a trigger again.
Register | Value | Direction | Description | |
SPC_TRIGGERMODE | 40000 | r/w | Sets the triggermode for the board. | |
| TM_TTLBOTH | 20030 | Sets the trigger mode for external TTL trigger to detect positive and negative edges. | |
Pulsewidth triggers
TTL pulsewidth trigger for long HIGH pulses
This mode is for detecting HIGH pulses of an external TTL signal that are longer than a programmed pulsewidth. If the pulse is shorter than the programmed pulsewidth, no trigger will be de- tected. The board will trigger on the first pulse matching the trig- ger condition after starting the board. The next triggerevent will then be detected, if the actual recording/replay has finished and the board is armed and waiting for a trigger again.
Register | Value | Direction | Description | |
SPC_PULSEWIDTH | 44000 | r/w | Sets the pulsewidth in samples. Values from 2 to 255 are allowed. | |
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SPC_TRIGGERMODE | 40000 | r/w | Sets the triggermode for the board. | |
| TM_TTLHIGH_LP | 20001 | Sets the trigger mode for external TTL trigger to detect HIGH pulses that are longer than a programmed pulsewidth. | |
TTL pulsewidth trigger for short HIGH pulses
This mode is for detecting HIGH pulses of an external TTL signal that are shorter than a programmed pulsewidth. If the pulse is longer than the programmed pulsewidth, no trigger will be detect- ed. The board will trigger on the first pulse matching the trigger condition after starting the board. The next triggerevent will then be detected, if the actual recording/replay has finished and the board is armed and waiting for a trigger again.
Register | Value | Direction | Description | |
SPC_PULSEWIDTH | 44000 | r/w | Sets the pulsewidth in samples. Values from 2 to 255 are allowed. | |
SPC_TRIGGERMODE | 40000 | r/w | Sets the triggermode for the board. | |
| TM_TTLHIGH_SP | 20002 | Sets the trigger mode for external TTL trigger to detect HIGH pulses that are shorter than a programmed pulsewidth. | |
64 | MC.31xx Manual |
