Structure Of 8-Bit Serial I/O-1 - Fujitsu F2MC-8L MB89620 Series Hardware Manual

3
10.

Structure of 8-bit Serial I/O-1

This section describes the pins, pin block diagram, registers, and interrupt source of 8-
bit serial I/O-1.
n 8-bit Serial I/O-1 Pins
8-bit serial I/O-1 uses the P33/SI1, P32/SO1, and P31/SCK1 pins.
l P33/SI1 pin
The P33/SI1 pin can function either as a general-purpose I/O port (P33) or as the serial data
input (hysteresis input) for 8-bit serial I/O-1 (SI1).
Set the P33/SI1 pin as an input port in the port data direction register (DDR3: bit 3 = "0") when
using as the SI1 pin.
P32/SO1 pin
l
The P32/SO1 pin can function either as a general-purpose I/O port (P32) or as the serial data
output for 8-bit serial I/O-1 (SO1).
Enabling serial data output (SMR1: SOE = "1") automatically sets the P32/SO1 pin as an output
pin, regardless of the port data direction register (DDR3: bit 2) value, and sets the pin to function
as the SO1 pin.
P31/SCK1 pin
l
The P31/SCK1 pin can function either as a general-purpose I/O port (P31) or as the shift clock
I/O for 8-bit serial I/O-1 (SCK1).
• When using as the shift clock input pin
When using SCK1 as an input pin, set the pin as an input port in the port data direction
register (DDR3: bit 1 = "0") and disable shift clock output (SMR1: SCKE = "0"). In this case,
always select external shift clock operation (SMR1: CKS1, CKS0 = "11
• When using as the shift clock output pin
Enabling shift clock output (SMR1: SCKE = "1") automatically sets the P31/SCK1 pin as an
output pin, regardless of the port data direction register (DDR3: bit 1) value, and sets the pin
to function as the SCK1 output pin. In this case, always select internal shift clock operation
(SMR1: CKS1, CKS0 = other than "11
202
CHAPTER 10 8-BIT SERIAL I/O (SERIAL I/O-1 AND SERIAL I/O-2)
").
B
").
B
MB89620 series