S1C8F626 TECHNICAL MANUAL
EPSON
49
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (I/O Ports)
■ DC output control
P00D–P07D: 00FF62H
P10D–P17D: 00FF63H
P20D–P27D: 00FF6AH
How I/O port terminal Pxx data readout and output
data settings are performed.
When writing data:
When "1" is written: HIGH level
When "0" is written: LOW level
When the I/O port is set to output mode, the data
written is output as is to the I/O port terminal. In
terms of port data, when "1" is written, the port
terminal goes to HIGH (VDD) level and when "0" is
written to a LOW (VSS) level.
Even when the port is in input mode, data can still be
written in.
When reading out data:
When "1" is read:
HIGH level ("1")
When "0" is read:
LOW level ("0")
When an I/O port is in input mode, the voltage level
being input to the port terminal is read out.
When terminal voltage is HIGH (VDD), it is read as a
"1", and when it is LOW (VSS), it is read as a "0".
Furthermore, in output mode, the contents of the data
register are read out.
At initial reset, this register is set to "1" (HIGH level).
Note: The data registers of the ports that are
configured to the serial interface outputs and
special outputs can be used as general
purpose registers that do not affect the
terminal inputs/outputs.
IOC00–IOC07: 00FF60H
IOC10–IOC17: 00FF61H
IOC20–IOC27: 00FF68H
Sets the I/O ports to input or output mode.
When "1" is written: Output mode
When "0" is written: Input mode
Reading:
Valid
IOCxx is the I/O control register which correspond to
each I/O port in a bit unit.
Writing "1" to the IOCxx register will switch the
corresponding I/O port Pxx to output mode, and
writing "0" will switch it to input mode.
When the special output is used, "1" must always be
set for the I/O control registers (IOC14–IOC17) of I/
O ports which will become output terminals.
At initial reset, this register is set to "0" (input mode).
Note: The I/O control registers of the ports that are
configured to the serial interface inputs/
outputs and special outputs can be used as
general purpose registers that do not affect
the terminal inputs/outputs.
IFLP10–IFLP17: 00FF67H
IFLP20–IFLP27: 00FF6EH
Selects an input interface level.
When "1" is written: CMOS Schmitt level
When "0" is written: CMOS level
Reading:
Valid
IFLPxx is the input I/F level select register
corresponding to the I/O ports P10–P17 and P20–
P27.
When "1" is written to IFLPxx, the corresponding I/
O port Pxx is configured with a CMOS Schmitt
level input interface. When "0" is written, the port is
configured with a CMOS level input interface.
At initial reset, this register is set to "0" (CMOS
level).
PULP00–PULP07: 00FF64H
PULP10–PULP17: 00FF65H
PULP20–PULP27: 00FF6CH
The pull-up during the input mode are set with
these registers.
When "1" is written: Pull-up ON
When "0" is written: Pull-up OFF
Reading:
Valid
PULPxx is the pull-up control register
corresponding to each I/O port (in bit units).
By writing "1" to the PULPxx register, the
corresponding I/O ports are pulled up (during
input mode), while writing "0" turns the pull-up
function OFF.
At initial reset, these registers are all set to "1", so
the pull-up function is set to ON.
Note: The pull-up control registers of the ports that
are configured to the serial interface outputs
or special outputs can be used as general
purpose registers that do not affect the pull-
up control. The pull-up control registers of
the port that are configured to the serial
interface inputs function the same as the I/O
port.