User`s manual

Writing and Reading Data

8-35

Note that the ValuesSent property value includes the terminator since each

occurrence of

\n in the command sent to the device is replaced with the

Terminator property value.

s.Terminator

ans =

The default value of Terminator is the line feed character. The terminator

required by your device will be described in its documentation.

Synchronous Versus Asynchronous Write Operations. By default, fprintf operates

synchronously and will block the MATLAB command line until execution

completes. To write text data asynchronously to the device, you must specify

async as the last input argument to fprintf.

fprintf(s,'Display:Contrast 45','async')

Asynchronous operations do not block access to the MATLAB command line.

Additionally, while an asynchronous write operation is in progress, you can:

•Execute an asynchronous read operation since serial ports have separate

pins for reading and writing

•Make use of all supported callback properties

You can determine which asynchronous operations are in progress with the

TransferStatus property. If no asynchronous operations are in progress, then

TransferStatus is idle.

s.TransferStatus

ans =

idle

Rules for Completing a Write Operation with fprintf.

A synchronous or asynchronous

write operation using

fprintf completes when:

•The specified data is written.

•The time specified by the

Timeout property passes.

Additionally, you can stop an asynchronous write operation with the

stopasync function.