Spectrum Brands MC.31XX manual Triggerlevel, Spctriggermode Tmchor, SPCTRIGGERMODE0 Tmchxoff

Trigger modes and appendant registers Channel Trigger

If you want to set up a four channel board to detect a triggerevent on either a positive edge on channel1 or a negative edge on channel3 you would have to set up your board as the following example shows.

SpcSetParam (hDrv,	SPC_TRIGGERMODE ,	TM_CHOR );	// Enable channel OR trigger mode
SpcSetParam (hDrv,	SPC_TRIGGERMODE0,	TM_CHXOFF);	// Disable channel0 concerning trigger detection
SpcSetParam (hDrv, SPC_TRIGGERMODE1, TM_CHXPOS);			// Set triggermode of channel1 to positive edge trigger
SpcSetParam (hDrv,	SPC_TRIGGERMODE2,	TM_CHXOFF);	// Disable channel2 concerning trigger detection
SpcSetParam (hDrv, SPC_TRIGGERMODE3, TM_CHXNEG);			// Set triggermode of channel3 to positive edge trigger
SpcSetParam (hDrv, SPC_TRIGGERMODE4,		TM_CHXOFF );	// Disable channel4 concerning trigger detection
SpcSetParam (hDrv, SPC_TRIGGERMODE5,		TM_CHXOFF );	// Disable channel5 concerning trigger detection
SpcSetParam (hDrv, SPC_TRIGGERMODE6,		TM_CHXOFF );	// Disable channel6 concerning trigger detection
SpcSetParam (hDrv, SPC_TRIGGERMODE7,		TM_CHXOFF );	// Disable channel7 concerning trigger detection

Triggerlevel

All of the channel trigger modes listed above require at least one triggerlevel to be set (except TM_CHXOFF of course). Some like the window trigger require even two levels (upper and lower level) to be set. Before explaining the different channel trigger modes, it is necessary to explain the board’s series specific range of triggerlevels.

After the data has been sampled, the upper N data bits are compared with the N bits of the trigger levels. The amount of bits, the trigger levels are represented with depends on the board’s series. The following table shows the level registers and the possible values they can be set to for your specific board.

8 bit resolution for the trigger levels:

Register	Value	Direction	Description	Range
SPC_HIGHLEVEL0	42000	r/w	Defines the upper level (triggerlevel) for channel 0	-127 to +127
SPC_HIGHLEVEL1	42001	r/w	Defines the upper level (triggerlevel) for channel 1	-127 to +127
SPC_HIGHLEVEL2	42002	r/w	Defines the upper level (triggerlevel) for channel 2	-127 to +127
SPC_HIGHLEVEL3	42003	r/w	Defines the upper level (triggerlevel) for channel 3	-127 to +127
SPC_HIGHLEVEL4	42004	r/w	Defines the upper level (triggerlevel) for channel 4	-127 to +127
SPC_HIGHLEVEL5	42005	r/w	Defines the upper level (triggerlevel) for channel 5	-127 to +127
SPC_HIGHLEVEL6	42006	r/w	Defines the upper level (triggerlevel) for channel 6	-127 to +127
SPC_HIGHLEVEL7	42007	r/w	Defines the upper level (triggerlevel) for channel 7	-127 to +127
SPC_LOWLEVEL0	42100	r/w	Defines the lower level (triggerlevel) for channel 0	-127 to +127
SPC_LOWLEVEL1	42101	r/w	Defines the lower level (triggerlevel) for channel 1	-127 to +127
SPC_LOWLEVEL2	42102	r/w	Defines the lower level (triggerlevel) for channel 2	-127 to +127
SPC_LOWLEVEL3	42103	r/w	Defines the lower level (triggerlevel) for channel 3	-127 to +127
SPC_LOWLEVEL4	42104	r/w	Defines the lower level (triggerlevel) for channel 4	-127 to +127
SPC_LOWLEVEL5	42105	r/w	Defines the lower level (triggerlevel) for channel 5	-127 to +127
SPC_LOWLEVEL6	42106	r/w	Defines the lower level (triggerlevel) for channel 6	-127 to +127
SPC_LOWLEVEL7	42107	r/w	Defines the lower level (triggerlevel) for channel 7	-127 to +127

In the above table the values for the triggerlevels represent the digital values for the corresponding data width N of the triggerlevels. If for example the triggerlevels are represented by 8 bit, the bipolar range would be -128 … 127. To archieve symmetric triggerlevels the most negative value is not used and the so resulting range would be -127 … +127.

As the triggerlevels are compared to the digitized data, the triggerlevels depend on the channels input range. For every input range available to your board there is a corresponding range of triggerlevels. On the different input ranges the possible stepsize for the triggerlevels differs as well as the maximum and minimum values. The following table, gives you the absolute triggerlevels for your specific board’s series.

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