UPD78F0411GA-GAM-AX Datasheet, PDF (315/564 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 13 SERIAL INTERFACE UART0
13.1 Functions of Serial Interface UART0
Serial interface UART0 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 13.4.1 Operation stop mode.
(2) Asynchronous serial interface (UART) mode
The functions of this mode are outlined below.
For details, see 13.4.2 Asynchronous serial interface (UART) mode and 13.4.3
generator.
Dedicated baud rate
• Maximum transfer rate: 625 kbps
• Two-pin configuration TXD0: Transmit data output pin
RXD0: Receive data input pin
• Length of communication data can be selected from 7 or 8 bits.
• Dedicated on-chip 5-bit baud rate generator allowing any baud rate to be set
• Transmission and reception can be performed independently (full-duplex operation).
• Fixed to LSB-first communication
Cautions 1. If clock supply to serial interface UART0 is not stopped (e.g., in the HALT mode), normal
operation continues. If clock supply to serial interface UART0 is stopped (e.g., in the STOP
mode), each register stops operating, and holds the value immediately before clock supply
was stopped. The TXD0 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 POWER0 = 0, RXE0 = 0, and TXE0 = 0.
2. Set POWER0 = 1 and then set TXE0 = 1 (transmission) or RXE0 = 1 (reception) to start
communication.
3. TXE0 and RXE0 are synchronized by the base clock (fXCLK0) set by BRGC0. To enable
transmission or reception again, set TXE0 or RXE0 to 1 at least two clocks of base clock
after TXE0 or RXE0 has been cleared to 0. If TXE0 or RXE0 is set within two clocks of base
clock, the transmission circuit or reception circuit may not be initialized.
4. Set transmit data to TXS0 at least one base clock (fXCLK0) after setting TXE0 = 1.
User’s Manual U18698EJ1V0UD
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