Barracuda RV8 Manual - Trigger Mode
System 3
4-19
RV8 Barracuda
Trigger Mode
The first circuit requires three additional components: LinGate gates the output on
and off, Schmitt opens and closes the gate and Src (Soft1) starts the Schmitt
trigger. The second circuit requires that the Barracuda be controlled from the trigger
mode. Trigger mode is accessible within RPvdsEx or from the ActiveX controls.
TimeStamp
The TimeStamp component is unique to the Barracuda and Multifunction Processor
(RX6). The event-timer, with its submicrosecond accuracy, is independent of the
sample period. This allows users to have separate control of both slow processes,
such as button presses, and fast events, such as neural activity, all on one circuit
with little or no loss of processing power.
PCM DAC Outs
The PCM DACs have a sample delay of only 2 samples. This makes them ideal for
use with time critical presentation of signals. These DACs are excellent for
neurophysiological stimulation for examining motor behavior.
Multiple Triggering
Multiple triggers allow users to repeatedly trigger the Barracuda without resetting
(Halting and then Running the chain). To use multiple triggering with RPvdsEx add
the bit-masked value of 128 to the Special Mode value. For example, to configure
the Barracuda for multiple triggering from the zBUSTrigA, you would set the value to
1 (Trigger Enabled) + 16 (ZbusTRIGA) + 128 (multiple triggers). RPvdsEx has
no way to control the number of presentations.
To generate an RPvdsEx circuit for multiple triggering, use the Setup Device
command on the Implement menu to open the Set Hardware Parameters dialog box,
then modify the Special Mode register. Use the bit-masked values for the Special
Mode to make a circuit trigger off either the zBUS or external trigger. In general this
will be 1(trigger mode enabled) + (trigger type) + 128 (mTrig enabled).
The multiple trigger does not require the addition of the trigger component. The
circuit runs when the trigger pulses high. The RPvdsEx circuit will trigger for a near
infinite number of times before stopping.
Arbitrary Sample Rates
The Barracuda is the only System 3 module that has arbitrary sample rates. To set
the arbitrary sample, click Device Setup on the Implement menu, and then set the
sample rate in the Arbitrary Sample Rate box. To check the true sample rate, click
Check Realizable. This will display the true sample rate. Sample periods are in
increments of 40 nanoseconds. To calculate the true sample rate determine the