Channel Trigger | Trigger modes and appendant registers |
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Channel pulsewidth trigger for long positive pulses
The analog input is continuously sampled with the selected sample rate. If the programmed triggerlevel is crossed by the channel’s signal from lower to higher values (rising edge) the pulsewidth counter is started. If the signal crosses the triggerlevel again in the opposite direction within the the programmed pulsewidth time, no trigger will be detect- ed. If the pulsewidth counter reaches the programmed amount of samples, without the signal crossing the trigger- level in the opposite direction, the triggerevent will be de- tected.
The pulsewidth trigger modes for long pulses can be used to prevent the board from triggering on wrong (short) edges in noisy signals.
Register | Value | Direction | set to | Value |
SPC_TRIGGERMODE | 40000 | r/w | TM_CHANNEL | 20040 |
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SPC_TRIGGERMODE0 | 40200 | r/w | TM_CHXPOS_LP | 10001 |
SPC_HIGHLEVEL0 | 42000 | r/w | Set it to the desired triggerlevel relatively to the channel’s input range. | board dependant |
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SPC_PULSEWIDTH | 44000 | r/w | Set to the desired pulsewidth in samples. | 2 to 255 |
Channel pulsewidth trigger for long negative pulses
The analog input is continuously sampled with the selected sample rate. If the programmed triggerlevel is crossed by the channel’s signal from higher to lower values (falling edge) the pulsewidth counter is started. If the signal crosses the triggerlevel again in the opposite direction within the the programmed pulsewidth time, no trigger will be detect- ed. If the pulsewidth counter reaches the programmed amount of samples, without the signal crossing the trigger- level in the opposite direction, the triggerevent will be de- tected.
The pulsewidth trigger modes for long pulses can be used to prevent the board from triggering on wrong (short) edges in noisy signals.
Register | Value | Direction | set to | Value |
SPC_TRIGGERMODE | 40000 | r/w | TM_CHANNEL | 20040 |
SPC_TRIGGERMODE0 | 40200 | r/w | TM_CHXNEG_LP | 10011 |
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SPC_HIGHLEVEL0 | 42000 | r/w | Set it to the desired triggerlevel relatively to the channel’s input range. | board dependant |
SPC_PULSEWIDTH | 44000 | r/w | Set to the desired pulsewidth in samples. | 2 to 255 |
70 | MC.31xx Manual |
