Structure Of 8-Bit Serial I/O-2 - Fujitsu F2MC-8L MB89620 Series Hardware Manual

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10.

Structure of 8-bit Serial I/O-2

This section describes the pins, pin block diagram, registers, and interrupt source of 8-
bit serial I/O-2.
n 8-bit Serial I/O-2 Pins
8-bit serial I/O-2 uses the P47/SI2, P46/SO2, and P45/SCK2 pins.
l P47/SI2 pin
The P47/SI2 pin can function either as a general-purpose I/O port (P47) or as the serial data
input (hysteresis input) for 8-bit serial I/O-2 (SI2).
Set "1" in the port data register (PDR4: bit 7) to turn "OFF" the output transistor and set the pin
as an input port when using as the SI2 pin.
P46/SO2 pin
l
The P46/SO2 pin can function either as a general-purpose I/O port (P46) or as the serial data
output (N-ch open-drain output) for 8-bit serial I/O-2 (SO2).
Enabling serial data output (SMR2: SOE = "1") automatically sets the pin as an output pin,
regardless of the output latch (PDR4: bit 6) value, and sets the pin to function as the SO2 pin.
P45/SCK2 pin
l
The P45/SCK2 pin can function either as a general-purpose I/O port (P45) or as the shift clock
I/O pin (hysteresis input, N-ch open-drain output) for 8-bit serial I/O-2 (SCK2).
• When using as the shift clock input pin
When using SCK2 as an input pin, set the pin as an input port by setting "1" in the port data
register (PDR4: bit 5) and disable shift clock output (SMR2: SCKE = "0"). In this case, always
select external shift clock operation (SMR2: CKS1, CKS0 = "11
• When using as the shift clock output pin
Enabling shift clock output (SMR2: SCKE = "1") automatically sets the P45/SCK2 pin as an
output pin, regardless of the output latch (PDR4: bit 5) value, and sets the pin to function as
the SCK2 output pin. In this case, always select internal shift clock operation (SMR2: CKS1,
CKS0 = other than "11
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CHAPTER 10 8-BIT SERIAL I/O (SERIAL I/O-1 AND SERIAL I/O-2)
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MB89620 series