Extended Baud Rate Generation; Receiver Muting And Wake-Up Feature - STMicroelectronics ST72361 Auto Series Manual

ST72361xx-Auto
RR = 1, 2, 4, 8, 16, 32, 64, 128
(see SCR[2:0] bits)
All these bits are in the SCIBRR register.
Example 1: If f
and receive baud rates are 38400 baud.
Note: The baud rate registers MUST NOT be changed while the transmitter or the receiver is
enabled.
16.4.5

Extended baud rate generation

The extended prescaler option gives a very fine tuning on the baud rate, using a 255 value
prescaler, whereas the conventional baud rate generator retains industry standard software
compatibility.
The extended baud rate generator block diagram is described in the
The output clock rate sent to the transmitter or to the receiver is the output from the 16
divider divided by a factor ranging from 1 to 255 set in the SCIERPR or the SCIETPR
register.
Note: The extended prescaler is activated by setting the SCIETPR or SCIERPR register to a value
other than zero. The baud rates are calculated as follows:
with:
ETPR = 1...255 (see SCIETPR register)
ERPR = 1...255 (see SCIERPR register)
16.4.6

Receiver muting and wake-up feature

In multiprocessor configurations it is often desirable that only the intended message
recipient should actively receive the full message contents, thus reducing redundant SCI
service overhead for all non addressed receivers.
The non addressed devices may be placed in sleep mode by means of the muting function.
Setting the RWU bit by software puts the SCI in sleep mode:
All the reception status bits cannot be set.
All the receive interrupts are inhibited.
A muted receiver may be awakened by one of the following two ways:
●
By idle line detection if the WAKE bit is reset,
●
By address mark detection if the WAKE bit is set.
Receiver wakes-up by idle line detection when the receive line has recognized an idle frame.
Then the RWU bit is reset by hardware but the IDLE bit is not set.
LINSCI serial communication interface (LIN master only)
is 8 MHz (normal mode) and if PR = 13 and TR = RR = 1, the transmit
CPU
f
CPU
Tx =
16 ETPR*(PR*TR)
*
Doc ID 12468 Rev 3
f
CPU
Rx =
16 ERPR*(PR*RR)
*
Figure 90.
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