M38203M4 Datasheet, PDF (229/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.6 Serial I/O2
sTransmit operation of the serial I/O2
Transmit operation of the serial I/O2 is described below (When LSB first is selected).
qStart of transmit operation
A transmit operation is started by writing transmit data into the serial I/O2 register (address 001F16)
in the transmit enable state.^V1
qTransmit operation
ŒThe transmit data written in the serial
I/O2 register is output from the P51/SOUT2
pin in synchronization with the falling of the
shift clocks.
b0
D7 D6 D5 D4 D3 D2 D1
Serial I/O2 register
D0
P51/SOUT2
The data is output from the least significant
bit of the serial I/O2 register. Each time 1-bit
data is output, the data of the serial I/O2
register is shifted by 1 bit toward the least
significant bit.
b0
D7 D6 D5 D4 D3 D2
Serial I/O2 register
D1
P51/SOUT2
ŽWhen 8-bit transmit data has been transferred,
the serial I/O2 interrupt request bit is set to
“1” in synchronization with the rising of a shift
clock.^V2
b0
Serial I/O2 register
Interrupt request ⁰
register 2
[Address 3D16] 1
b6
D7
P51/SOUT2
V1: Initialization of register or others for a trans-
mit operation. Refer to “2.6.4 Register set-
ting example.”
V2: When an internal clock is used as a syn-
chronizing clock, supplying the shift clock
to the serial I/O2 register stops automati-
cally at the completion of 8-bit transmis-
sion.
3820 GROUP USER’S MANUAL
2–143