Overview Of The I/O Port - Fujitsu FR60 Hardware Manual

CHAPTER 5 I/O PORT
5.1

Overview of the I/O Port

This section provides an overview of the I/O port.
■ Basic Block Diagram of the I/O Port
The MB91301 series interface can be used as an I/O port if settings are made so that the
external bus interface or peripherals corresponding to pins do not use the pins as input/output
pins.
Figure 5.1-1 shows the basic configuration of the I/O port.
Internal Bus
Peripheral output
PDR
PFR
DDR
PCR
Note:
For port output, the pull-up resistor register is invalid regardless of the setting.
The I/O port consists of PDRs (Port Data Registers), DDRs (Data Direction Registers),
PFRs (Port Function Registers) and PCR (Pull-up Resistance Control Registers).
258
Figure 5.1-1 Port Block with Pull-up
Periphral input
PDR read
1
0
PCR=0: No pull-up resistor
PCR=1:With pull-up resistor
0
1
PDR :Port Data Register
DDR :Data Direction Register
PFR :Port Function Register
PCR :Pull-up Resistor Control Register
approx.
Pin