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CHAPTER 14 SERIAL INTERFACE UART6
User’s Manual U19780EJ2V0UD
363
Cautions 1. The T
X
D6 output inversion function inverts only the transmission side and not the reception
side. To use this function, the reception side must be ready for reception of inverted data.
2. If clock supply to serial interface UART6 is not stopped (e.g., in the HALT mode), normal
operation continues. If clock supply to serial interface UART6 is stopped (e.g., in the STOP
mode), each register stops operating, and holds the value immediately before clock supply
was stopped. The T
X
D6 pin also holds the value immediately before clock supply was
stopped and outputs it. However, the operation is not guaranteed after clock supply is
resumed. Therefore, reset the circuit so that POWER6 = 0, RXE6 = 0, and TXE6 = 0.
3. Set POWER6 = 1 and then set TXE6 = 1 (transmission) or RXE6 = 1 (reception) to start
communication.
4. TXE6 and RXE6 are synchronized by the base clock (f
XCLK6
) set by CKSR6. To enable
transmission or reception again, set TXE6 or RXE6 to 1 at least two clocks of the base clock
after TXE6 or RXE6 has been cleared to 0. If TXE6 or RXE6 is set within two clocks of the
base clock, the transmission circuit or reception circuit may not be initialized.
5. Set transmit data to TXB6 at least one base clock (f
XCLK6
) after setting TXE6 = 1.
6. If data is continuously transmitted, the communication timing from the stop bit to the next
start bit is extended two operating clocks of the macro. However, this does not affect the
result of communication because the reception side initializes the timing when it has
detected a start bit. Do not use the continuous transmission function if the interface is
used in LIN communication operation.
Remark
LIN stands for Local Interconnect Network and is a low-speed (1 to 20 kbps) serial communication
protocol intended to aid the cost reduction of an automotive network.
LIN communication is single-master communication, and up to 15 slaves can be connected to one
master.
The LIN slaves are used to control the switches, actuators, and sensors, and these are connected to the
LIN master via the LIN network.
Normally, the LIN master is connected to a network such as CAN (Controller Area Network).
In addition, the LIN bus uses a single-wire method and is connected to the nodes via a transceiver that
complies with ISO9141.
In the LIN protocol, the master transmits a frame with baud rate information and the slave receives it and
corrects the baud rate error. Therefore, communication is possible when the baud rate error in the slave
is
±
15% or less.