Spectrum Brands MI.61XX Trigger modes and appendant registers

58 MI.61xx Manual

General Description Trigger modes and appendant registers

Trigger modes and appendant registers

Concerning the trigger modes of the Spectrum MI, MC and MX D/A boards, you can choose between three external TTL trigger modes and

one internal software trigger. This chapter is about to explain the different trigger modes and setting up the board’s registers for the desired

mode. Every analog Spectrum board has one dedicated SMB connector mounted in it’s bracket for feeding in an external trigger signal or

outputting a trigger signal of an internal trigger event. As only one connector is available for external trigger I/O, it is not possible to forward

the external trigger signal that is fed in to another board. If this is necessary, you need to first split up the external trigger signal.

The software trigger is the easiest way of triggering any Spectrum

board. The acquisition or replay of data will start immediately af-

ter starting the board. The only delay results from the time the

board needs for its setup.

In addition to the softwaretrigger (free run) it is also possible to force a triggerevent by software while the board is waiting for an internal or

external trigger event. Therefore you can use the board command shown in the following table.

Due to the fact that the software trigger is an internal trigger mode, you can optionally enable the external trigger output to generate a high

active trigger signal, which indicates when the data acquisition or replay begins. This can be useful to synchronize external equipment with

your Spectrum board.

Example for setting up the software trigger:

Enabling the external trigger input is performed by one of the following external trigger modes. The dedicated register for that operation is

shown below.

If you choose an external trigger mode the SPC_TRIGGEROUT register will be overwritten and the trigger connector will be used as an input

by default.

SPC_TRIGGERMODE 40000 r/w Sets the triggermode for the board.

TM_SOFTWARE 0 Sets the trigger mode to software, so that the recording/replay starts immediately.

SPC_COMMAND 0 r/w Command register of the board.

SPC_FORCETRIGGER 16 Forces a trigger event if the hardware is still waiting for a trigger event. Needs a base board hardware version > 7.x.

SPC_TRIGGEROUT 40100 r/w Defines the data direction of the external trigger connector.

0 The trigger connector is not used and the line driver is disabled.

1 The trigger connector is used as an output that indicates a detected internal trigger event.

SpcSetParam (hDrv, SPC_TRIGGERMODE, TM_SOFTWARE); // Internal software trigger mode is used

SpcSetParam (hDrv, SPC_TRIGGEROUT , 1 ); // And the trigger output is enabled

SPC_TRIGGERMODE 40000 r/w

TM_TTLPOS 20000 Sets the trigger mode for external TTL trigger to detect positive edges.

TM_TTLNEG 20010 Sets the trigger mode for external TTL trigger to detect negative edges

TM_TTLBOTH 20030 Sets the trigger mode for external TTL trigger to detect positive and negative edges

SPC_TRIGGEROUT 40100 r/w Defines the data direction of the external trigger connector.

X If external triggermodes are used, this register will have no effect.