Barracuda RV8 User Manual

RV8Barracuda

Note: This device is no longer available for new purchase.

4-13

RV8Overview

The Barracuda features include nanosecond accurate event-timing, fast DAC's for
high frequency stimulus presentation and user control of sample frequencies. In
addition the Barracuda gives users precise control over stimulus presentation. The
system has 16-digital inputs, 8-digital outputs, and 8 analog outputs.

PowerandCommunication

The RA16 mounts in a System 3 zBus Powered Device Chassis (ZB1PS) and
communicates with the PC using any of the zBus PC interfaces. The ZB1PS is UL
compliant, see the

SoftwareControl

Software control is implemented with circuit files developed using TDT's RP Visual
Design Studio (RPvdsEx). Circuits are loaded to the processor through TDT run­time applications or custom applications. This manual includes device specific
information needed during circuit design. For circuit design techniques and a complete
reference of the RPvdsEx circuit components, see the

NanosecondEvent‐Timing

ZB1PS Operations Manual

for power and safety information.

RPvdsEx Manual

.

The Barracuda is a nanosecond accurate event timer. The TimeStamp component
uses the high-speed clock on the system to record when a TTL event occurred
during a sampling period. This means that event times are independent of sample
rate. When an event occurs the TimeStamp sends out the time in microseconds from
the start of that sample period. At the end of each sample period the event timer is
reset to zero. In the figure below three events occurred during a sample period of

RV8 Barracuda

4-14 System 3

ten microseconds. For each digital input a unique time stamp is recorded for that
sample period.

TimeStampDiagram

FastDigital‐AnalogConverters

The Barracuda ships with PCM DAC's with up to 500 kHz sample rate. The fast
DAC's can be used for high frequency presentations. In addition the Barracuda's PCM
DAC's give users precise control over voltage outputs for microelectrode stimulation.

VariableSampleFrequency

The Barracuda allows users to set the sample period in 40 nanosecond steps. Users
can select sample frequency from 10 to 500,000 Hz.

UserControlofSystemDevices

The Barracuda has two control modes: Free-run and Triggered. In Free-run mode
the circuit runs continuously and gating functions are required to control the signal
outputs and inputs. In Trigger mode the circuit only runs after it has been triggered.
It then runs for a set number of samples and then stops. The system can be
triggered once or multiple times. The circuit must be reset before it can trigger
again. Gating functions are not required for turning on and off stimuli.

AdditionalFeatures

To simplify signal synchronization it is possible to send out the sample clock and the
system clock (50 MHz) on the digital outputs. Users can also send out the sample
clock period.

BarracudaFeatures

Trigger

Takes an external TTL pulse and triggers components (free run mode) or triggers
the circuit (trigger mode).

RV8 Barracuda

System 3 4-15

StatusLights

The status lights indicate the state of the RV8. Armed, Running, (DoCount), and
FreeRun. Combinations of the status light describe the state of the RV8.

Free Run Mode

Free Run Mode w/

Circuit Running

Trigger Mode

Trigger Mode with

System Armed

Trigger Mode with

System Running:

DigitalInputLights

Lights are on when there is a TTL pulse on the digital input line. Pulse times may
be too brief to see in many cases. Only channels 0-7 have indicator lights.

DigitalOutputLights

Lights are on when a TTL pulse is sent out of a digital output line. All eight
channels (0-7) have a TTL indicator light.

25‐pinConnectorforDigitalInputsandOutputs

A 25-pin connector gives access to all 24 channels of digital I/O. The pin outs for
the connector are shown in “Barracuda Technical Specifications” on page 4-21. TDT
provides the PP16 with 24 connectors to give users easy access to all the digital
output channels of the Barracuda.

BarracudaDeviceSetup

The Barracuda has several additional features not found in other RP devices. An
expanded dialog box opens after selecting the RV8 option.

RV8 Barracuda