MB95630H Series
MN702-00009-1v0-E
FUJITSU SEMICONDUCTOR LIMITED
215
CHAPTER 14 LIN-UART
14.5 LIN-UART Baud Rate
14.5.1
Baud Rate Setting
This section shows baud rate settings and the result of calculating the serial
clock frequency.
■
Baud Rate Calculation
The two 15-bit reload counters are set by the LIN-UART baud rate generator registers 1, 0
(BGR1, BGR0).
The equation for the baud is shown below.
Reload value:
v = (
) - 1
v: Reload value, b: Baud rate, MCLK: Machine clock, or external clock frequency
Calculation example
Assuming that the machine clock is 10 MHz, the internal clock is used, and the baud rate is set
to 19200 bps:
Reload value:
Thus, the actual baud rate can be calculated as shown below.
Note:
The reload counter stops if the reload value is set to "0". Therefore, set the smallest
reload value to "1".
For transmission/reception in asynchronous mode, since five times of oversampling have
to be done before the reception value is determined, the reload value must be set to at
least "4".
v = (
10
×
10
6
) -1
=
519.83...
≈
520
19200
b =
MCLK
=
10
×
10
6
= 19193.8579
(v + 1)
521
MCLK
b