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Sensoray 2600 Programming Guide 72 Comport Transaction Functions

8.4.3 S26_ComClearFlags()

Function: Resets all error flags belonging to a comport.

Prototype: u32 S26_ComClearFlags( u32 hbd, u8 LogDev, u32 msec, u32 retries );

Returns: Error/status value, as described in section 8.1.1.

Notes: If this function executes successfully, the COM_FRAMINGERROR, COM_PARITYERROR and COM_OVERFLOWERROR

flags will be reset to zero on the target comport. This will be reflected in the returned status byte as well.

Example: // Reset all COM1 error flags on MM number 0.

// For clarity, error detection is not shown here.

S26_ComClearFlags( 0, 1, 1000, 1 );

8.4.4 S26_ComFlush()

Function: Flushes a comport’s receiver buffer and resets its error flags.

Prototype: u32 S26_ComFlush( u32 hbd, u8 LogDev, u32 msec, u32 retries );

Returns: Error/status value, as described in section 8.1.1.

Notes: S26_ComFlush() may be used to “reset” the receiver buffer to compensate for a detected error on a received

character from the remote serial device; this has the effect of resynchronizing the Ethernet client to the remote

serial device.

This function should be called, for example, if a parity, framing or overrun error is detected on a received character.

When a receive error occurs, the entire contents of the receiver buffer must be considered corrupt and the receiver

buffer should accordingly be dumped in preparation for a communication retry to the remote serial device.

The target comport must be open when this function is called. If the comport is already closed when this command

is issued, the command will be rejected and the status byte’s COM_REJECTED flag will be set.

Example: // Fetch and display an ASCII string from COM1 on MM number 0.

char RcvBuf[256]; // Buffer that will receive the string.

u16 BufLen = sizeof(RcvBuf); // Max number of characters to receive.

u32 errstat = S26_ComReceive( 0, 1, RcvBuf, &BufLen, 1000, 1 );

if ( errstat & GWERRMASK )

printf( "COM1 error detected.\n" );

else if ( errstat & ( COM_PARITYERROR | COM_OVERFLOWERROR | COM_FRAMINGERROR ) )

{

Parameter Type Description

hbd u32

MM handle.

LogDev u8

Logical device identifier for the target comport. Specify a value from 1 to 4 to

address comport 1 to 4, respectively.

msec u32

Maximum time, in milliseconds, to wait for the MM to respond.

retries u32

Maximum number of transaction retry attempts.