Lin-Uart Baud Rate - Fujitsu 8FX Hardware Manual

MB95630H Series
14.5

LIN-UART Baud Rate

The input clock (transmit/receive clock source) of the LIN-UART can be
selected from one of the following:
• Input a machine clock to a baud rate generator (reload counter).
• Input an external clock to a baud rate generator (reload counter).
• Use an external clock (SCK pin input clock) directly.
■ LIN-UART Baud Rate Selection
The baud rate can be selected from one of following three types. Figure 14.5-1 shows the baud
rate selection circuit.
● Baud rate derived from the internal clock divided by the dedicated baud rate generator
(reload counter)
There are two internal reload counters, corresponding to the transmit serial clock and the
receive serial clock respectively. The baud rate is selected by setting a 15-bit reload value in
the LIN-UART baud rate generator registers 1, 0 (BGR1, BGR0).
The reload counter divides the internal clock by the value set in BGR1 and BGR0.
The baud rate is used in asynchronous mode and in synchronous mode (transmit side of the
serial clock).
As for clock source settings, select the internal clock and use the baud generator clock
(SMR:EXT = 0, OTO = 0).
● Baud rate derived from the external clock divided by the dedicated baud rate generator
(reload counter)
The external clock is used as the clock source for the reload counter.
The baud rate is selected by setting a 15-bit reload value in the LIN-UART baud rate generator
registers 1, 0 (BGR0, BGR1).
The reload counter divides the external clock by the value set in BGR1 and BGR0.
The baud rate is used in asynchronous mode.
As for clock source settings, select the external clock and use the baud generator clock
(SMR:EXT = 1, OTO = 0).
● Baud rate by the external clock (one-to-one mode)
The clock input from the clock input pin (SCK) of the LIN-UART is used as the baud rate
(slave operation in operating mode 2 (synchronous) (ECCR:MS = 1)).
It is used in synchronous mode (serial clock reception side).
As for clock source settings, select the external clock and its direct use (SMR:EXT = 1,
OTO = 1).
MN702-00009-2v0-E FUJITSU SEMICONDUCTOR LIMITED
CHAPTER 14 LIN-UART
14.5 LIN-UART Baud Rate
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