Specifications

II-28 EPSON S1C62N82 TECHNICAL SOFTWARE
CHAPTER 3: PERIPHERAL CIRCUITS (I/O Ports)
The S1C62N82 contains a 4-bit general I/O port (4 bits × 1).
This port can be used as an input port or an output port,
according to I/O port control register IOC. When IOC is "0",
the port is set for input, when it is "1", the port is set for
output.
• How to set an input port
Set "0" in the I/O port control register (D0 of address 0FCH),
and the I/O port is set as an input port. The state of the I/O
port (P00–P03) is decided by the data of address 0F6H. (In
the input mode, the port level is read directly.)
• How to set an output port
Set "1" in the I/O port control register, and the I/O port is
set as an output port. The state of the I/O port is decided by
the data of address 0F6H. This data is held by the register,
and can be set regardless of the contents of the I/O control
register. (The data can be set whether P00 to P03 ports are
input ports or output ports.)
The I/O control registers are cleared to "0" (input/output
ports are set as input ports), and the data registers are also
cleared to "0" after an initial reset.
• Loading P00–P03 input data into A register
Label Mnemonic/operand Comment
LD Y,0FCH ;Set address of I/O control port
AND MY,1110B ;Set port as input port
LD Y,0F6H ;Set address of port
LD A,MY ;A register ← P00–P03
Control of
the I/O port
Examples of I/O port
control
program