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. Since 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

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

[baud,swfc,hwfc,par,term] = strread(data,'%d%d%d%s%s', 
'delimiter',';')
baud =
        9600
swfc =
     0
hwfc =
     0
par = 
    'NONE'
term = 
    '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