Fig. 2.7.7 Connection Example For Serial I/O Transmit/Receive; Fig. 2.7.8 Serial Data Transmit/Receive Processing Sequence - Renesas 7200 Series User Manual

FUNCTIONAL DESCRIPTION
2.7 Serial I/O
The transmit side in Figure 2.7.7, P2
I/O synchronous clock output pin by the initialization program.
The receive side, P2
clock (external clock) input pin by the initialization program.
Figure 2.7.8 shows the serial data transmit/receive processing sequence using the above structure.
Transmit Side
Serial I/O Mode Register
b7
0 1 1
M37221M6-XXXSP/FP

Fig. 2.7.7 Connection example for serial I/O transmit/receive

Transmit side
LDM #$0C, $DC
CLB 2, $FD
SEB 2, $FF
LDM #DATA, $DD ; Write transfer data to serial
As a result of the above processing 1-byte data is transferred from the transmit side to the receive side.
When the transmit operation is completed, interrupts occur on both sides, so that completion of the data
transfer can be reported.
After that, repeating the processing after the symbol ( ) can transmit/receive more data.

Fig. 2.7.8 Serial data transmit/receive processing sequence

2-46
is set as the serial I/O data output pin and P2
1
is set as the serial I/O data input pin and P2
1
b0
Internal synchronous clock selection bits
Synchronous clock selection bit
1: Internal clock
Serial I/O port selection bit
1: S , S
CLK OUT
Fix this bit to "0."
Transfer direction selection bit
Serial input pin selection bit
Nothig is assigned.
P2 /S
0
P2 /S
1
; Set serial I/O mode register.
; Reset serial I/O interrupt
request bit.
; Set the serial I/O interrupt
enable bit to "1."
I/O register.
7220 Group User's Manual
Synchronous clock
S
CLK CLK
Serial data
S
OUT OUT
LDM #$48, $DC
CLB 2, $FD
SEB 2, $FF
LDM #$FF, $DD
0
is used for the serial I/O synchronous
0
Receive Side
Serial I/O Mode Register
b7
b0
1 0 1 0
Internal synchronious clock selection bits
Synchronous clock selection bit
0: External clock
Serial I/O port selection bit
1: S
CLK
Fix this bit to "0."
Transfer direction selection bit
Serial input pin selection bit
1: Input signal from S
Nothig is assigned.
/P2
0
/P2
1
M37221M6-XXXSP/FP
Receive side
; Set serial I/O mode
register.
; Reset serial I/O interrupt
request bit.
; Set serial I/O interrupt
enable bit to "1."
; Write dummy data to
serial I/O register.
is set as the serial
, S
OUT
pin
OUT