Overview Of The I/O Port - Fujitsu MB91319 Series Hardware Manual

CHAPTER 4 I/O PORT
4.1

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 pins of this LSI device can be used as I/O ports if settings are made so that the
corresponding pins are not used for the inputs and outputs of the peripheral circuits.
Figure 4.1-1 shows the basic configuration of the port.
Port Bus
Peripheral output
The I/O port consists of PDRs (Port Data Registers), DDRs (Data Direction Registers), and PFRs
(Port Function Registers).
128
Figure 4.1-1 Basic Block Diagram of the I/O Port
Peripheral output
1
PDR
0
PFR
DDR
0
1
PDR: Port Data Register
DDR: Data Drection Register
PFR: Port Function Register
Pin