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Preliminary User’s Manual U16035EJ1V0UM
CHAPTER 14 SERIAL INTERFACE (SIO3)
The serial interface (SIO3) incorporates two 3-wire serial I/O mode channels (SIO30, SIO31).
These two channels have exactly the same functions.
14.1 Functions of Serial Interface
The serial interface (SIO3n) has the following two modes.
(1) Operation stop mode
This mode is used when serial transfers are not performed. For details, see
14.4.1 Operation stop mode
.
(2) 3-wire serial I/O mode (fixed as MSB first)
This is an 8-bit data transfer mode using three lines: a serial clock line (SCK3n), serial output line (SO3n), and
serial input line (SI3n).
Since simultaneous transmit and receive operations are enabled in 3-wire serial I/O mode, the processing time
for data transfers is reduced.
The first bit of the serial transferred 8-bit data is fixed as the MSB.
3-wire serial I/O mode is useful for connection to a peripheral I/O incorporating a clocked serial interface, or a
display controller, etc. For details see
14.4.2 3-wire serial I/O mode
.
Figure 14-1 shows a block diagram of the serial interface (SIO3n).
Remark
n = 0, 1
Figure 14-1. Block Diagram of Serial Interface (SIO3n)
Note
SI30, SO30, and SCK30 pins are shared with P20, P21, and P22 pins. SI31, SO31, and SCK31 pins are
shared with P34, P35, and P36 pins.
Remark
n = 0, 1
Internal bus
8
Serial clock
controller
Serial clock
counter
Interrupt
request signal
generator
Selector
Serial I/O shift register
3n (SIO3n)
SI3n
Note
SO3n
Note
SCK3n
Note
INTCSI3n
f
X
/2
3
f
X
/2
4
f
X
/2
5
