Data Format - NEC uPD784038 Series User Manual

CHAPTER 17 ASYNCHRONOUS SERIAL INTERFACE/3-WIRE SERIAL I/O

17.2.3 Data Format

Serial data transmission/reception is performed in full-duplex asynchronous mode.
The transmit/receive data format is shown in Figure 17-5. 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 17-5 Asynchronous Serial Interface Transmit/Receive Data Format
• Start bit ························ 1 bit
• Character bits ············· 7 bits/8 bits
• Parity bit ······················ Even parity/odd parity/0 parity/no parity
• Stop bit s ····················· 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.
Start
D0 D1 D2 D3
Bit
User's Manual U11316EJ4V1UD
1 Data Frame
Parity
D4 D5 D6 D7
Bit
Stop
Bit(s)
421