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SetSerialTATxRValues

long SetSerialTATxRValues( long bps, char *divisor, int tatXr );

Description

Sets up the possibly shared serial timer (TATxR) resources required to achieve, as closely as possible, the requested serial bps rate. The algorithm attempts to find, when necessary and if possible, the lowest value for the TAT1R that will precisely produce the requested serial bps rate. For this reason, an application that requires the TAT1R to be shared should generally first set up its usage with (1) the most critical timer A1 cascade rate, or (2) the lowest timer A1 cascade rate. That is, consider setting up the most critical stage (PWM, servo, triac, ultra-precise serial rate, etc.) first, else set up the slowest usage (often, the lowest serial rate) first.

Note that this function provides no TATxR resource sharing protection for an application that uses any of the individual TATxR resources either directly or indirectly. For example, this function affords no protection to an application that sets a direct usage TAT7R timer interrupt and also opens serial port D such that TAT7R is used to set the serial data rate.

A run time error occurs if parameter(s) are invalid. Also, this function is not reentrant.

Parameters

bps

The requested serial bits per second (BPS, baud) rate.

divisor

An optional pointer to the caller's serial timer divisor variable. If the caller is not interested in the actual serial timer (TATxR) divisor value that is set by this function, then NULL may be passed.

tatXr

The TATxR for the serial timer whose value(s) are to be set. Use exactly one of the following macros:

• TAT4R for serial port A

• TAT5R for serial port B

• TAT6R for serial port C

• TAT7R for serial port D

• TAT2R for serial port E

• TAT3R for serial port F

Return Value

The actual serial rate BPS (baud) setting that was achieved.

Library

sys.lib

See Also

TAT1R_SetValue