External Interfaces Reference |
Write binary data to the device
Syntax
Arguments
Description
fwrite(obj,A)
writes the binary data A
to the device connected to obj
.
fwrite(obj,A,'
writes binary data with precision specified by precision
')
precision
.
precision
controls the number of bits written for each value and the interpretation of those bits as integer, floating-point, or character values. If precision
is not specified, uchar
(an 8-bit unsigned character) is used. The supported values for precision
are listed below in Remarks.
writes binary data with command line access specified by fwrite(obj,A,'
mode
')
mode
. If mode
is sync
, A
is written synchronously and the command line is blocked. If mode
is async
, A
is written asynchronously and the command line is not blocked. If mode
is not specified, the write operation is synchronous.
writes binary data with precision specified by fwrite(obj,A,'
precision
','
mode
')
precision
and command line access specified by mode
.
Remarks
Before you can write data to 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 write operation while obj
is not connected to the device.
The ValuesSent
property value is increased by the number of values written each time fwrite
is issued.
An error occurs if the output buffer cannot hold all the data to be written. You can specify the size of the output buffer with the OutputBufferSize
property.
If you use the help
command to display help for fwrite
, then you need to supply the pathname shown below.
Synchronous Versus Asynchronous Write Operations
By default, data is written to the device synchronously and the command line is blocked until the operation completes. You can perform an asynchronous write by configuring the mode
input argument to be async
. For asynchronous writes:
BytesToOutput
property value is continuously updated to reflect the number of bytes in the output buffer.
OutputEmptyFcn
property is executed when the output buffer is empty.
You can determine whether an asynchronous write operation is in progress with the TransferStatus
property.
Synchronous and asynchronous write operations are discussed in more detail in Writing Data.
Rules for Completing a Write Operation with fwrite
A binary write operation using fwrite
completes when:
Timeout
property passes.
Note
The Terminator property is not used with binary write operations.
|
Supported Precisions
The supported values for precision
are listed below.
Functions
Properties
BytesToOutput
, OutputBufferSize
, OutputEmptyFcn
, Status
, Timeout
, TransferStatus
, ValuesSent
fscanf (serial) | get (serial) |
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