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EPSON
S1C63558 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (I/O Ports)
ESIF: Serial interface (1) enable register (FF70H•D0)
Selects function for P10–P13.
When "1" is written: Serial interface (1) input/output port
When "0" is written: I/O port
Reading: Valid
When using the serial interface (1), write "1" to this register and when P10–P13 are used as the I/O port,
write "0". The terminal configuration within P10–P13 that are used for the serial interface (1) is decided by
the transfer mode (7-bit asynchronous, 8-bit asynchronous, clock synclonous slave, clock synchronous
master) selected with the SMD1 and SMD0 registers.
In the clock synchronous slave mode, all the P10–P13 ports are set to the serial interface (1) input/output
port. In the clock synchronous master mode, P10–P12 are set to the serial interface (1) input/output port
and P13 can be used as the I/O port. In the 8/7-bit asynchronous mode, P10 and P11 are set to the serial
interface (1) input/output port and P12 and P13 can be used as the I/O port.
At initial reset, this register is set to "0".
ESIFS: Serial interface (2) enable register (FF58H•D0)
Selects function for P30–P33.
When "1" is written: Serial interface (2) input/output port
When "0" is written: I/O port
Reading: Valid
When using the serial interface (2), write "1" to this register and when P30–P33 are used as the I/O port,
write "0". The terminal configuration within P30–P33 that are used for the serial interface (2) is decided by
the transfer mode (7-bit asynchronous, 8-bit asynchronous, clock synclonous slave, clock synchronous
master) selected with the SMD1S and SMD0S registers.
In the clock synchronous slave mode, all the P30–P33 ports are set to the serial interface (2) input/output
port. In the clock synchronous master mode, P30–P32 are set to the serial interface (2) input/output port
and P33 can be used as the I/O port. In the 8/7-bit asynchronous mode, P30 and P31 are set to the serial
interface (2) input/output port and P32 and P33 can be used as the I/O port.
At initial reset, this register is set to "0".
(2) I/O port control
P00–P03: P0 I/O port data register (FF42H)
P10–P13: P1 I/O port data register (FF46H)
P20–P23: P2 I/O port data register (FF4AH)
P30–P33: P3 I/O port data register (FF4EH)
I/O port data can be read and output data can be set through these registers.
• When writing data
When "1" is written: High level
When "0" is written: Low level
When an I/O port is set to the output mode, the written data is output unchanged from the I/O port
terminal. When "1" is written as the port data, the port terminal goes high (V
DD
), and when "0" is written,
the terminal goes low (V
SS
).
Port data can be written also in the input mode.
• When reading data
When "1" is read: High level
When "0" is read: Low level
The terminal voltage level of the I/O port is read out. When the I/O port is in the input mode the voltage
level being input to the port terminal can be read out; in the output mode the register value can be read.
