M38203M4 Datasheet, PDF (200/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.5 Serial I/O1
sTransfer data format
Data transfer format is set by the UART control register (address 001B16). Figure 2.5.9 shows a
transfer data format in the UART mode, Table 2.5.2, the each bit function of UART transmit data,
Figure 2.5.10, all transfer data formats in the UART mode.
qFor 1ST–8DATA–1PA–2SP
Transmit data
Data bit (8 bits)
LSB
ST D0 D1
MSB
D6 D7 PA
Next transmit data
(at continuous output)
SP SP ST D0 D1
Fig. 2.5.9 Transfer data format in UART mode
Table 2.5.2 Each bit function of UART transmit data
Bit
ST
(Start bit)
DATA
(Data bit)
PA
(Parity bit)
SP
(Stop bit)
Functions
Indicates a start of data transmission. A “L” signal for one bit is added just before transmit
data.
Indicates the transmit data written in the transmit buffer register, “02” data is a “L” signal
and “12” data is a “H” signal. These bits are called as character bits.
To improve the reliability of data, this bit is added just after the last data bit. The value
of this bit changes in accordance with the value of the parity selection bit so that the
number of “1” in the transmit/receive data (including the parity bit) can always be an even
or an odd number.
Indicates an completion of data transmission. This bit is added just after the last data bit
(or just after a parity bit in the parity checking enabled). As a stop bit, a “H” signal for 1
bit or 2 bits is output.
2–114
3820 GROUP USER’S MANUAL