Sensoray 2410 API User Manual

Page 38

Sensoray 24xx Programming Guide

Model 2426 Multi-Function I/O Module

7.5.4 s2426_ComportWrite()

Function:

Enqueue data for transmission on the comport.

Prototype:

u32 s2426_ComportWrite( HSESSION sess, u32 *err, void *buf, int len, BOOL wait );

Returns:

Number of data bytes that were enqueued for transmission. If an error occurs, zero is returned and an error code is
stored in

err

Notes:

This function copies data from

buf

to the comport’s transmit FIFO. The comport consumes byte data from the

FIFO output and transmits the bytes onto the comport’s physical interface. Data bytes are transmitted in the same
order they were enqueued. Previously enqueued, but unsent data pending in the FIFO will be transmitted before
new data. This function doesn’t actually transmit data on the comport; it only enqueues data for later transmission.

wait

is False and the transmit FIFO would overflow as a result of enqueing all of the new data, only a portion of

the data will be enqueued and the returned value will be less than

len

The comport must be attached to the specified session when this function is called. If the comport is closed, the
function will return zero and

err

will be set to

COMPORT_UNATTACHED

Example:

// Send a text string to the comport.

char

msg[] = "This is a test\n";

u32 err = ERR_NONE;
u32 len =

sizeof

(msg) - 1;

// exclude NUL char at end of string

u32 nsent = s2426_ComSend( sess, &err, msg, len, TRUE );

( nsent == len )

printf( "sent string\n" );

else if

( err != ERR_NONE )

printf( "Error: %s\n", s24xx_ErrorText(err) );

else

printf( "Error: no data sent\n" );

Argument

Description

sess

Session handle obtained from

s24xx_SessionOpen()

err

Pointer to error code. See Section 4.3.1 for details.

buf

Pointer to a buffer that contains data to be enqueued for transmission.

len

Number of bytes to be enqueued.

wait

Enable blocking operation. When True, this function will return when data has been
enqueued or upon error. When False, the function will return immediately regardless
of whether data was successfully enqueued.