M38203M4 Datasheet, PDF (231/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.6 Serial I/O2
sReceive operation of the serial I/O2
Receive operation of the serial I/O2 is described below (When LSB first is selected).
qStart of receive operation
A receive operation is started by writing the following data into the serial I/O2 register (address
001F16) in the receive enable state.^V1
•Transmit data in the full duplex data transfer mode
•Arbitrary dummy data in the half duplex data transfer mode
qReceive operation
ŒEach 1-bit data is read into the serial I/O2
register from the P50/SIN2 pin in synchroni-
zation with the rising of the shift clocks.
D1
P50/SIN2
b0
D0
Serial I/O2 register
The data enters first into the most significant
bit of the serial I/O2 register. Each time 1-bit
data is received, the data of the serial I/O2
register is shifted by 1 bit toward the least
significant bit.
D4
P50/SIN2
b0
D3 D2 D1 D0
Serial I/O2 register
ŽWhen 8-bit receive data transfer is completed,
the serial I/O2 interrupt request bit is set to
“1” in synchronization with the rising of a shift
clock.^V2
P50/SIN2
D7 D6 D5 D4 D3 D2 D1 D0
Serial I/O2 register
Interrupt request 0
register 2
[Address 3D16] 1
b6
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
2–145