Digital Input/Output

This example shows how to set up digital inputs and outputs. In this example, a digital input is used to provide additional control over when a task transitions from one state to the next, and a digital output is used to indicate when a subject’s hand is in or out of a target. The digital input could be from a push-button that the experimenter has and the digital output could go to a speaker to provide audio output.

10.19.1      Simulink Code for Digital I/O Example

The Simulink code for this example is based on the code in 6.7 Centre-out Reaching Task. The differences are the addition a Digital Input block (PCI-6229 DI) and a Digital Output block (PCI-6229 DO), as well as the associated inputs/outputs in Trial_Control.

Figure 10.29: Simulink Code for Digital I/O Example

10.19.2      Stateflow Chart for Digital Input and Output Example

The Stateflow Chart shown below is based upon 10.18.2 Stateflow Chart for Parallel State Execution (Independent State Machines) Example, with a few modifications:

• A new transition from MoveTarget to EndOfTrial was added, based on the condition [Digital_Input==1]. Thus if the push button connected to digital input 1 is pressed when the task is in the MoveTarget state, then [Digital_Input==1] will become true and the transition will occur.
• HandInTarget_Output is a newly defined output whose value depends on the HandInTarget If [HandInTarget==1], then the Task Program will set HandInTarget_Output=1, which in this example is connected to a digital output that goes to a speaker, thus providing audio feedback on when a subject’s hand is in the desired target.

Figure 10.30: Stateflow Chart for Digital I/O Example

10.19.3     Connecting to National Instruments I/O When Using a PCI-6229

Most Kinarm Labs come with a National Instruments PCI-6229 I/O card and a BNC 2090A to interface with it. The table below shows how the labels on the BNC 2090A relate to the I/O channels specified in Simulink for the PCI-6229.

Table 10.3: BNC 2090A to PCI-6229 interface