ST10R272L - ASYNCHRONOUS/SYNCHRONOUS SERIAL INTERFACE
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12.4.2 Synchronous mode baud rates
For synchronous operation, the baud rate generator provides a clock with 4 times the rate of
the established baud rate. The baud rate for synchronous operation of serial channel ASC0
can be determined by the following formula:
<S0BRL> is the content of the reload register, taken as unsigned 13-bit integers,
<S0BRS> is the value of bit S0BRS (i.e. ‘0’ or ‘1’), taken as integer.
Using the above equation, the maximum baud rate can be calculated for any given clock
speed.
12.5
ASC0 interrupt control
Four bit addressable interrupt control registers are provided for serial channel ASC0.
Register S0TIC controls the transmit interrupt, S0TBIC controls the transmit buffer interrupt,
S0RIC controls the receive interrupt and S0EIC controls the error interrupt of serial channel
ASC0. Each interrupt source also has its own dedicated interrupt vector. S0TINT is the
transmit interrupt vector, S0TBINT is the transmit interrupt vector, S0RINT is the receive
interrupt vector, and S0EINT is the error interrupt vector.
The cause of an error interrupt request (framing, parity, overrun error) can be identified by
the error status flags in control register S0CON.
B
Sync
=
S0BRL = (
f
CPU
(8 + 4*<S0BRS>) * B
Sync
) - 1
f
CPU
(8 + 4*<S0BRS>) * (<S0BRL> + 1)
