Trigger modes and appendant registers
External logic trigger (X1, X2, X3)
(c) Spectrum Instrumentation GmbH
111
TTL pulsewidth trigger for long LOW pulses
This mode is for detecting LOW 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 trigger event will then be detected, if the actual record
-
ing/replay has finished and the board is armed and waiting for
a trigger again.
TTL pulsewidth trigger for short LOW pulses
This mode is for detecting LOW 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.
The following example shows, how to setup the card for using external TTL pulse width trigger on EXT1 (X1) input:
To find out what maximum pulsewidth (in samples) is available, please read out the register shown in the table below:
Register
Value
Direction
set to
Value
SPC_TRIG_EXT1_PULSEWIDTH
SPC_TRIG_EXT2_PULSEWIDTH
SPC_TRIG_EXT3_PULSEWIDTH
44211
44212
44213
read/write
Sets the pulsewidth in samples.
2 up to [4G -1]
SPC_TRIG_EXT1_MODE
SPC_TRIG_EXT2_MODE
SPC_TRIG_EXT3_MODE
40511
40512
40513
read/write
(SPC_TM_NEG | SPC_TM_PW_GREATER)
4000002h
Register
Value
Direction
set to
Value
SPC_TRIG_EXT1_PULSEWIDTH
SPC_TRIG_EXT2_PULSEWIDTH
SPC_TRIG_EXT3_PULSEWIDTH
44211
44212
44213
read/write
Sets the pulsewidth in samples.
2 up to [4G -1]
SPC_TRIG_EXT1_MODE
SPC_TRIG_EXT2_MODE
SPC_TRIG_EXT3_MODE
40511
40512
40513
read/write
(SPC_TM_NEG | SPC_TM_PW_SMALLER)
2000002h
// Setting up external X1 TTL trigger to detect low pulses that are longer than 50 samples ...
spcm_dwSetParam_i32 (hDrv,SPC_TRIG_EXT1_MODE, SPC_TM_NEG | SPC_TM_PW_GREATER);
spcm_dwSetParam_i64 (hDrv, SPC_TRIG_EXT1_PULSEWIDTH , 50);
spcm_dwSetParam_i32 (hDrv, SPC_TRIG_ORMASK, SPC_TMASK_EXT1); // ... and enable it in OR mask
Register
Value
Direction
Description
SPC_TRIG_EXT_AVAILPULSEWIDTH
44201
read
Contains the maximum possible value for the external trigger pulsewidth counter. Valid for all of the
external trigger sources.
Summary of Contents for M2p.59 Series
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