Trigger modes and appendant registers
Delay trigger
(c) Spectrum GmbH
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Delay trigger
All of the Spectrum M2i series cards allow the user to program an additional trigger delay. As shown in the trigger overview section, this
delay is the last element in the trigger chain. Therefore the user does not have to care for the sources when programming the trigger delay.
The following table shows the related register and the possible values. A value of 0 disables the extra delay. The resulting delays (due to the
internal structure of the card) can be found in the technical data section of this manual.
The example shows, how to use the delay trigger command:
Using the delay trigger does not affect the ratio between pre trigger and post trigger recorded number of samples, but only shifts
the trigger event itself. For changing these values, please take a look in the relating chapter about „Acquisition Modes“.
Please note that the trigger delay setting is not used when synchronizing cards. If you need a trigger delay
on synchronized systems it is necessary to program posttrigger, segmentsize and memsize to fulfill this task.
External TTL trigger
Enabling the external trigger input(s) is done, if you choose one of the following external trigger modes. The dedicated register for that op-
eration is shown below.
Using the SPC_TM_PULSESTRETCH mode requires driver version V2.11 (or newer) and firmware version V18
(or newer). Please update your system to the newest versions to use this mode.
For all external edge and level trigger modes, the OR mask must contain the corresponding input, as the following table shows:
Register
Value
Direction
Description
SPC_TRIG_AVAILDELAY
40800
read
Contains the maximum available delay as a decimal integer value.
SPC_TRIG_DELAY
40810
read/write
Defines the delay for the detected trigger events.
0
No additional delay will be added. The resulting internal delay is mentioned in the technical data section.
0…65535
Defines the additional trigger delay in number of sample clocks.
spcm_dwSetParam_i32 (hDrv, SPC_TRIG_DELAY, 2000); // A detected trigger event will be
// delayed for 2000 sample clocks.
Register
Value
Direction
Description
SPC_TRIG_EXT_AVAILMODES
40500
read
Bitmask, in which all bits of the below mentioned modes for the external trigger are set, if available.
SPC_TRIG_EXT0_MODE
40510
read/write
Defines the external TTL trigger mode for the external SMB connector (A/D and D/A boards only).
On digital boards this defines the TTL trigger mode for the trigger input of the first module (Mod A).
SPC_TRIG_EXT1_MODE
40511
read/write
Defines the external TTL trigger mode for the trigger input of the second module (digital boards only).
SPC_TRIG_XIO0_MODE
40560
read/write
Defines the trigger mode for the extra TTL input 0. On plain cards this input is only available if the
option BaseXIO is installed. As part of the digitizerNETBOX this input is available as connector Trig-
ger B.
SPC_TRIG_XIO1_MODE
40561
read/write
Defines the trigger mode for the extra TTL input 1. These trigger inputs are only available, when
option BaseXIO is installed.
SPC_TM_NONE
0h
Input is not used for trigger detection. This is as with the trigger masks another possibility for disabling TTL sources.
SPC_TM_POS
1h
Sets the trigger mode for external TTL trigger to detect positive edges.
SPC_TM_POS |
SPC_TM_PULSESTRETCH
10000001h
Sets the trigger mode for external TTL trigger to stretch and detect HIGH pulses.
SPC_TM_NEG
2h
Sets the trigger mode for external TTL trigger to detect negative edges
SPC_TM_NEG |
SPC_TM_PULSESTRETCH
10000002h
Sets the trigger mode for external TTL trigger to stretch and detect LOW pulses.
SPC_TM_BOTH
4h
Sets the trigger mode for external TTL trigger to detect positive and negative edges
SPC_TM_HIGH
8h
Sets the trigger mode for external TTL trigger to detect HIGH levels.
SPC_TM_LOW
10h
Sets the trigger mode for external TTL trigger to detect LOW levels.
SPC_TM_POS |
SPC_TM_PW_GREATER
4000001h
Sets the trigger mode for external TTL trigger to detect HIGH pulses that are longer than a programmed pulsewidth.
SPC_TM_POS |
SPC_TM_PW_SMALLER
2000001h
Sets the trigger mode for external TTL trigger to detect HIGH pulses that are shorter than a programmed pulsewidth.
SPC_TM_NEG |
SPC_TM_PW_GREATER
4000002h
Sets the trigger mode for external TTL trigger to detect LOW pulses that are longer than a programmed pulsewidth.
SPC_TM_NEG |
SPC_TM_PW_SMALLER
2000002h
Sets the trigger mode for external TTL trigger to detect LOW pulses that are shorter than a programmed pulsewidth.
Register
Value
Direction
Description
SPC_TRIG_ORMASK
40410
read/write
Defines the OR mask for the different trigger sources.
SPC_TMASK_EXT0
2h
Enable external trigger input for the OR mask
SPC_TMASK_XIO0
100h
Enable extra TTL input 0 for the OR mask. On plain cards this input is only available if the option BaseXIO is installed.
As part of the digitizerNETBOX this input is available as connector Trigger B.
SPC_TMASK_XIO1
200h
Enable extra TTL input 1 for the OR mask. These trigger inputs are only available, when option BaseXIO is installed.
