External Interfaces/API

Example: Parsing Input Data Using strread

This example illustrates how to use the strread function to parse and format data that you read from a device. strread is particularly useful when you want to parse a string into one or more variables, where each variable has its own specified format.

The instrument is a Tektronix TDS 210 two-channel oscilloscope connected to the serial port COM1.

1. Create a serial port object - Create the serial port object s associated with serial port COM1.

• s = serial('COM1');
  

2. Connect to the device - Connect s to the oscilloscope. Because the default value for the ReadAsyncMode property is continuous, data is asynchronously returned to the input buffer as soon as it is available from the instrument.

• fopen(s)
  

3. Write and read data - Write the RS232? command to the instrument using fprintf, and then read back the result of the command using fscanf. RS232? queries the RS-232 settings and returns the baud rate, the software flow control setting, the hardware flow control setting, the parity type, and the terminator.

• fprintf(s,'RS232?')
  data = fscanf(s)
  data =
  9600;0;0;NONE;LF
  

1. Use the strread function to parse and format the data variable into five new variables.

   • [br,sfc,hfc,par,tm] = strread(data,'%d%d%d%s%s','delimiter',';')
     
     br =
             9600
     sfc =
          0
     hfc =
          0
     par = 
         'NONE'
     tm = 
         'LF'
     

4. Disconnect and clean up - When you no longer need s, you should disconnect it from the instrument, and remove it from memory and from the MATLAB workspace.

• fclose(s)
  delete(s)
  clear s
  

Example: Writing and Reading Text Data

Example: Reading Binary Data