UPD784938 Datasheet, PDF (435/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 18 ASYNCHRONOUS SERIAL INTERFACE/3-WIRE SERIAL I/O
18.2.3 Data format
Serial data transmission/reception is performed in full-duplex asynchronous mode.
The transmit/receive data format is shown in Figure 18-5. One data frame is made up of a start bit, character bits, parity
bit, and stop bit(s).
Character bit length specification, parity selection and stop bit length specification for one data frame are performed by
means of the asynchronous serial interface mode register (ASIM).
Figure 18-5. Asynchronous Serial Interface Transmit/Receive Data Format
1 data frame
Start
bit
D0
D1
D2
D3
D4 D5
D6
D7
Parity
bit
Stop
bit(s)
• Start bit ························ 1 bit
• Character bits ············· 7 bits/8 bits
• Parity bits ···················· Even parity/odd parity/0 parity/no parity
• Stop bits ······················ 1 bit/2 bits
The serial transfer rate is selected in accordance with the asynchronous serial interface mode register and baud rate
generator settings. If a serial data receive error occurs, the nature of the receive error can be determined by reading the
asynchronous serial interface status register (ASIS) status.
Preliminary User’s Manual U13987EJ1V0UM00
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