M16C62_M Datasheet, PDF (391/615 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

UART
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
2.5 Clock-Asynchronous Serial I/O (UART) Usage
2.5.1 Overview of the clock-asynchronous serial I/O usage
UART handles communications by means of character-by-character synchronization. The transmission
side and the reception side are independent of each other, so full-duplex communication is possible. The
following is an overview of the clock-asynchronous serial I/O usage.
(1) Transmission/reception format
Figure 2.5.1 shows the transmission/reception format, and Table 2.5.1 shows the names and func-
tions of transmission data.
Transfer data length : 7 bits
Transfer data length : 8 bits
Transfer data length : 9 bits
1ST – 7DATA
1SP
1ST – 7DATA
2SP
1ST – 7DATA – 1PAR – 1SP
1ST – 7DATA – 1PAR – 2SP
1ST – 8DATA
1SP
1ST – 8DATA
2SP
1ST – 8DATA – 1PAR – 1SP
1ST – 8DATA – 1PAR – 2SP
1ST – 9DATA
1SP
1ST – 9DATA
2SP
1ST – 9DATA – 1PAR – 1SP
1ST – 9DATA – 1PAR – 2SP
ST : Start bit
DATA : Character bit (Transfer data)
PAR : Parity bit
SP : Stop bit
Figure 2.5.1. Transmission/reception format
Table 2.5.1. Transmission data names and functions
Name
ST (start bit)
Function
A 1-bit “L” signal to be added immediately before character bits.
This bit signals the start of data transmission.
DATA (character bits) Transmission data set in the UARTi transmit buffer register.
PAR (parity bit)
A signal to be added immediately after character bits so as to increase data
reliability. The level of this signal so varies that the total number of 1's in
character bits and this bit always becomes even or odd depending on which
parity is chosen, even or odd.
SP (stop bit)
Either 1-bit or 2-bit “H” signal to be added immediately after character bits (after
the parity bit if parity is checked). This / they signals the end of data
transmission.
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