ST72F324BK6TAS STMicroelectronics, ST72F324BK6TAS Datasheet - Page 118

• Manufacturer Part Number: ST72F324BK6TAS
• Description: 8-BIT MCU
• Manufacturer: STMicroelectronics

On-chip peripherals
Note:
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Conventional baud rate generation
The baud rate for the receiver and transmitter (Rx and Tx) are set independently and
calculated as follows:
with:
PR = 1, 3, 4 or 13 (see SCP[1:0] bits)
TR = 1, 2, 4, 8, 16, 32, 64,128
(see SCT[2:0] bits)
RR = 1, 2, 4, 8, 16, 32, 64,128
(see SCR[2:0] bits)
All these bits are in the
Example: If f
receive baud rates are 38400 baud.
The baud rate registers MUST NOT be changed while the transmitter or the receiver is
enabled.
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 output clock rate sent to the transmitter or to the receiver will be the output from the 16
divider divided by a factor ranging from 1 to 255 set in the SCIERPR or the SCIETPR
register.
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
page 128.
ERPR = 1,.. 255, see
page 128
CPU
is 8 MHz (normal mode) and if PR = 13 and TR = RR = 1, the transmit and
SCI Extended Transmit Prescaler Division Register (SCIETPR) on
SCI Extended Receive Prescaler Division Register (SCIERPR) on
SCI Baud Rate Register (SCIBRR) on page
Tx =
Tx =
16
Doc ID13466 Rev 4
(16
*
ETPR*(PR*TR)
f
CPU
*
f
PR)
CPU
*
TR
Rx =
Rx =
16
*
ERPR*(PR*RR)
(16
f
CPU
f
*
CPU
PR)
*
RR
Figure
127.
57.
ST72324B-Auto