
Mode Gated Sampling
Trigger
(c) Spectrum Instrumentation GmbH
141
LOW TTL level trigger
This mode is for detecting the low levels of an external TTL signal.
The gate will start on low levels that are detected after starting the
board.
As this mode is purely level-triggered, the low level at the cards
start time, does trigger the board.
With the next high level the gate will be stopped.
TTL pulsewidth trigger for long HIGH pulses
This mode is for detecting a rising edge of an external TTL signal
followed by a HIGH pulse that are longer than a programmed
pulsewidth. If the pulse is shorter than the programmed pulse
-
width, no trigger will be detected.
The gate will start on the first pulse matching the trigger condition
after starting the board.
The gate will stop with the next falling edge.
TTL pulsewidth trigger for long LOW pulses
This mode is for detecting a falling edge of an external TTL signal
followed by a LOW pulse that are longer than a programmed
pulsewidth. If the pulse is shorter than the programmed pulse
-
width, no trigger will be detected.
The gate will start on the first pulse matching the trigger condition
after starting the board.
The gate will stop with the next rising edge.
The following example shows, how to setup the card for using external TTL pulse width trigger on EXT1 (X1) input:
Register
Value
Direction
set to
Value
SPC_TRIG_EXT1_MODE
SPC_TRIG_EXT2_MODE
SPC_TRIG_EXT3_MODE
40511
40512
40513
read/write
SPC_TM_LOW
10h
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_POS | SPC_TM_PW_GREATER)
4000001h
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
// 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
Содержание M2p.59 Series
Страница 190: ......