CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U15195EJ5V0UD
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10.3.5 Operation
(1) Data format
Full-duplex serial data is transmitted and received.
Figure 10-17 shows the format of transmit/receive data. One data frame consists of a start bit, character bits,
a parity bit, and a stop bit(s). When 2 data frame transfer is set, both frames have the above-described
format.
Specification of the character bit length in one data frame, parity selection, and specification of the stop bit
length is done using asynchronous serial interface mode register 10 (ASIM10). Specification of the number
of frames and specification of the extension bit is mode using asynchronous serial interface mode register 11
(ASIM11). Data is transmitted LSB first.
Figure 10-17. Asynchronous Serial Interface Transmit/Receive Data Format
(a) 1-frame format
1 frame
Data
Stop bit
Start
bit
Parity/
extension
bit
D0
D1
D2
D3
D4
D5
D6
D7
(b) 2-frame format
Higher frame
Lower frame
Data
D8 D9 D10 D11 D12 D13 D14 D15
D0 D1 D2 D3 D4 D5 D6 D7
Start
bit
Parity
bit
Stop
bit
Parity
bit
Stop
bit
Start
bit
• Start bit ... 1 bit
• Character bits ... 7 or 8 bits
• Parity bit ... Even parity, odd parity, 0 parity, or no parity
• Stop bit ... 1 or 2 bits
Caution The extension bit is invalid in the 2-frame continuous mode or when a parity bit is added.