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M2i.30xx / M2i.30xx-exp Manual
Channel Trigger
Trigger modes and appendant registers
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.
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 triggerevent will
then be detected, if the actual recording/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:
To find out what maximum pulsewidth (in samples) is available, please read out the register shown in the table below:
Channel Trigger
Overview of the channel trigger registers
The channel trigger modes are the most commonly used ones, similar to external equipment like oscilloscopes. The huge variety of different
channel trigger modes enable you to observe nearly any part of the analog signal. This chapter is about to explain the different modes in
detail. To enable the channel trigger, you have to set the channel triggermode register accordingly. Therefore you have to choose, if you
Register
Value
Direction
set to
Value
SPC_TRIG_EXT0_PULSEWIDTH
44210
read/write
Sets the pulsewidth in samples.
2 up to 65535
SPC_TRIG_EXT0_MODE
40510
read/write
(SPC_TM_POS | SPC_TM_PW_SMALLER)
2000001h
Register
Value
Direction
set to
Value
SPC_TRIG_EXT0_PULSEWIDTH
44210
read/write
Sets the pulsewidth in samples.
2 up to 65535
SPC_TRIG_EXT0_MODE
40510
read/write
(SPC_TM_NEG | SPC_TM_PW_GREATER)
4000002h
Register
Value
Direction
set to
Value
SPC_TRIG_EXT0_PULSEWIDTH
44210
read/write
Sets the pulsewidth in samples.
2 up to 65535
SPC_TRIG_EXT0_MODE
40510
read/write
(SPC_TM_NEG | SPC_TM_PW_SMALLER)
2000002h
spcm_dwSetParam_i32 (hDrv,SPC_TRIG_EXT0_MODE, SPC_TM_NEG | SPC_TM_PW_GREATER); // Setting up external TTL
// trigger to detect low pulses
spcm_dwSetParam_i32 (hDrv, SPC_TRIG_EXT0_PULSEWIDTH , 50); // that are longer than 50 samples.
spcm_dwSetParam_i32 (hDrv, SPC_TRIG_ORMASK, SPC_TMASK_EXT0); // and enable it within the OR mask
Register
Value
Direction
Description
SPC_TRIG_EXT_AVAILPULSEWIDTH
44200
read
Contains the maximum possible value for the external trigger pulsewidth counter.
