Serial I/O; Structure Of Serial I/O; Serial I/O Register (Address 00Dd ) - Renesas 7200 Series User Manual

FUNCTIONAL DESCRIPTION

2.7 Serial I/O

2.7 Serial I/O
The M37221M6-XXXSP/FP has on-chip clock synchronous serial I/O which can receive and transmit 8-bit
data serially.
Because pin S also can be used as the serial I/O data input pin, it can transmit and receive with only
OUT
one signal line.

2.7.1 Structure of serial I/O

Serial I/O consists of
Serial I/O register
Serial I/O mode register
Serial I/O counter
Clock source generating counter
The serial I/O register is the register which 8-bit transfer data is written into. Each function of serial I/O
can be controlled by setting appropriate values to the serial I/O mode register.
Serial I/O transfers data to and from the internal CPU via the data bus, and it transfers data to and from
external devices via ports P2
P2 : Serial I/O synchronous clock input/output pin (S
0
P2 : Serial I/O data input/output pin (S
1
P2 : Serial I/O data input pin (S
2
The functions of these ports can be selected by the serial I/O mode register.
The transfer clock that determines the serial data transfer rate can selected 4 kinds of clock sources with
the serial I/O mode register.
Figure 2.7.1 shows the serial I/O block diagram, Figure 2.7.2 shows the serial I/O mode register.
2-40
–P2 . When using the serial I/O, ports P2
2 0
)
OUT
)
IN
7220 Group User's Manual
–P2 have the following functions:
2 0
)
CLK