|MATLAB Function Reference|
Read data from the device, and format as text
||A serial port object.
||C language conversion specification.
||The number of values to read.
||Data read from the device and formatted as text.
||The number of values read.
||A message indicating if the read operation was unsuccessful.
A = fscanf(obj)
reads data from the device connected to
obj, and returns it to
A. The data is converted to text using the
A = fscanf(obj,' reads data and converts it according to
format is a C language conversion specification. Conversion specifications involve the
% character and the conversion characters d, i, o, u, x, X, f, e, E, g, G, c, and s. Refer to the
sscanf file I/O format specifications or a C manual for more information.
A = fscanf(obj,' reads the number of values specified by
size. Valid options for
||Read at most
||Read at most m-by-n values filling an m-by-n matrix in column order.
size cannot be
inf, and an error is returned if the specified number of values cannot be stored in the input buffer. If
size is not of the form
[m,n], and a character conversion is specified, then
A is returned as a row vector. You specify the size, in bytes, of the input buffer with the
InputBufferSize property. An ASCII value is one byte.
[A,count] = fscanf(...)
returns the number of values read to
[A,count,msg] = fscanf(...)
returns a warning message to
msg if the read operation did not complete successfully.
Before you can read data from the device, it must be connected to
obj with the
fopen function. A connected serial port object has a
Status property value of
open. An error is returned if you attempt to perform a read operation while
obj is not connected to the device.
msg is not included as an output argument and the read operation was not successful, then a warning message is returned to the command line.
ValuesReceived property value is increased by the number of values read - including the terminator - each time
fscanf is issued.
If you use the
help command to display help for
fscanf, then you need to supply the pathname shown below.
Rules for Completing a Read Operation with fscanf
A read operation with
fscanf blocks access to the MATLAB command line until:
Terminatorproperty is read.
Create the serial port object
s and connect
s to a Tektronix TDS 210 oscilloscope, which is displaying sine wave.
fprintf function to configure the scope to measure the peak-to-peak voltage of the sine wave, return the measurement type, and return the peak-to-peak voltage.
Because the default value for the
ReadAsyncMode property is
continuous, data associated with the two query commands is automatically returned to the input buffer.
fscanf to read the measurement type. The operation will complete when the first terminator is read.
fscanf to read the peak-to-peak voltage as a floating-point number, and exclude the terminator.
s from the scope, and remove
s from memory and the workspace.