Chapter 15 Serial Interface Uart6; Functions Of Serial Interface Uart6 - NEC 78K0 Series User Manual

15.1 Functions of Serial Interface UART6

Serial interface UART6 has the following two modes.
(1) Operation stop mode
This mode is used when serial communication is not executed and can enable a reduction in the power
consumption.
For details, see 15.4.1 Operation stop mode.
(2) Asynchronous serial interface (UART) mode
This mode supports the LIN (Local Interconnect Network)-bus. The functions of this mode are outlined below.
For details, see 15.4.2
generator.
• Maximum transfer rate: 312.5 kbps
• Two-pin configuration
• Data length of communication data can be selected from 7 or 8 bits.
• Dedicated internal 8-bit baud rate generator allowing any baud rate to be set
• Transmission and reception can be performed independently (full duplex operation).
• MSB- or LSB-first communication selectable
• Inverted transmission operation
• Sync break field transmission from 13 to 20 bits
• More than 11 bits can be identified for sync break field reception (SBF reception flag provided).
Cautions 1. The T D6 output inversion function inverts only the transmission side and not the reception
X
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
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
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
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
incorporated in LIN.

CHAPTER 15 SERIAL INTERFACE UART6

Asynchronous serial interface (UART) mode and 15.4.3
T D6: Transmit data output pin
X
R D6: Receive data input pin
X
D6 pin also holds the value immediately before clock supply was
X
Preliminary User's Manual U17260EJ3V1UD
Dedicated baud rate
) set by CKSR6. To enable
XCLK6
) after setting TXE6 = 1.
XCLK6
347