MB96300 Super Series Hardware Manual
20.6.1
Setting the Baud Rate
This section describes how the baud rates are set and the resulting serial clock
frequency is calculated.
■ Calculating the baud rate
The both 16-bit reload counters are programmed by the baud rate generator registers (BGRn). The following
calculation formula should be used to set the desired baud rate:
Reload Value:
v = [Φ / b] - 1,
where Φ is the peripheral clock CLKP1, b the baud rate and [] gaussian brackets (mathematical rounding
function).
●
Example of calculation
If the peripheral clock CLKP1 is 16 MHz and the desired baud rate is 19200 bps baud then the reload value v
is:
v = [16*10
The exact baud rate can then be recalculated: b
Note:
Setting the reload value to 0 stops the reload counter. For this reason the minimum division ratio is 2. For
asynchronous communication, the reload value must be greater than equal to 4 because 5 times over-
sampling is performed internally.
6
/ 19200] - 1 = 832
= Φ / (v + 1), here it is: 16*10
exact
CHAPTER 20 USART
6
/ 833 = 19207.6831
505