M38203M4 Datasheet, PDF (193/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

‘At the time when a transmit shift operation
starts, the transmit shift register shift com-
pletion flag (bit 2) of the serial I/O1 status
register is cleared to “0.” ^V4
’At the time when the transmit shift operation
completes, the transmit shift register shift com-
pletion flag is set to “1.” ^{V2 V4}
V4: When an internal clock is used as a syn-
chronizing clock, supplying the shift clock
to the transmit shift register stops auto-
matically at the completion of 8-bit trans-
mission. However, when the next transmit
data is written to the transmit buffer regis-
ter while the transmit shift register shift com-
pletion flag is “0,” supplying the shift clock
is continued.
APPLICATION
2.5 Serial I/O1
b0
D7 D6 D5 D4 D3 D2 D1
Transmit shift register
Serial I/O1 status
register
[Address 1916]
D0
P45/TxD
1
0
b2
b0
Transmit shift register
Serial I/O1 status
register
[Address 1916]
D7
P45/TxD
0
1
b2
Shift clock
Transmit shift register
b7
b0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1
D0
D7 D6 D5 D4 D3 D2
D1
D7 D6 D5 D4 D3
D2
D7
Fig. 2.5.3 Transmit operation in clock synchronous mode
3820 GROUP USER’S MANUAL
2–107