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Getting Started Manual 27
4.3.6 Circular Buffer Functions
These functions act on or report status of the circular transmit/receive buffers.
Macro definitions are used to establish the buffer sizes:
xINBUFSIZE —read buffer size, where x is A, B, C, or D
xOUTBUFSIZE —write buffer size where x is A, B, C, or D
The user must define each buffer size for each port being used to be a power of 2 minus 1
with a macro. The size of 2^n - 1 enables masking for fast rollover calculations. If no
value or an illegal value is defined, a default size of 31 will be used and a compiler warn-
ing will be given. When using cofunctions, smaller buffer sizes can yield more frequently
to other tasks, but have the risk of a large input data stream overrunning the buffer and los-
ing data if the other task executes for too long relative to the baud rate.
int serXpeek ( );
Returns the first character in the receive buffer, if any are available, without removing it from the buffer.
Parameters
None
Return Value
An integer with return character in the low byte. No character is represented by a return of –1.
void serXrdFlush ( );
Flushes the serial port receive buffer.
Parameters
None
Return Value
None
void serXwrFlush ( );
Flushes the serial port transmit buffer.
Parameters
None
Return Value
None