Fujitsu 8FX Hardware Manual page 281

MB95630H Series
● Modifying sampling clock edge select bit (ESCR:SCES)
With the SCES bit set to "1", executing the LIN-UART software reset is prohibited.
• To modify the SCES bit from "0" to "1"
Disable
(SMR:UPCL = 1), then modify the SCES bit from "0" to "1".
• To modify the SCES bit from "1" to "0"
Disable reception and transmission, modify the SCES bit from "1" to "0", then executing a
LIN-UART software reset (SMR:UPCL = 1).
● Using LIN functions
The LIN functions are available in operating mode 3. In the same mode, the communication
format is predefined (8-bit data, no parity, one stop bit, LSB first).
While the length of the LIN synch break transmit bit is variable, in detection, the bit length is
fixed at 11 bits.
● LIN slave settings
Before the LIN-UART starts operating as a slave, the baud rate must be set before the first LIN
synch break is received to ensure that a LIN synch break whose length is a minimum of 13 bits
is successfully detected.
● Bus idle function
The bus idle function is not available in synchronous mode (operating mode 2).
● AD bit (LIN-UART serial control register (SCR): Address/data format select bit)
Pay attention to the following issues when using the AD bit.
The AD bit is used to select the address/data for transmission by writing a value to it. When the
AD bit is read, it returns the value of the AD bit received last. Inside the microcontroller, the
AD bit value received and the one transmitted are saved in separate registers.
The AD bit value transmitted is read when the read-modify-write (RMW) type of instruction is
used. Therefore, if another bit in the SCR register is accessed by bit access, an incorrect value
may be written to the AD bit.
For the above reason, set the AD bit at the last access to the SCR register before transmission.
The above problem can also be prevented by always using byte access to write values to the
SCR register.
● LIN-UART software reset
Execute the LIN-UART software reset (SMR:UPCL = 1) when the TXE bit in the LIN-UART
serial control register (SCR) is "0".
MN702-00009-2v0-E
reception and transmission,
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER 14 LIN-UART
14.8 Notes on Using LIN-UART
executing a LIN-UART software reset
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