User Manual

EP7309/11/12 User’s Manual - DS508UM4 11-1
Copyright Cirrus Logic, Inc. 2003
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Chapter 11
11General Purpose I/O (GPIO)
Introduction
GPIOs are user controlled pins that can be configured as independent input and
output data registers. In put or output data is read or written respectively to the
register address. Typical uses include keyboard interface, contr ol signal interface for
external peripherals, and data transfer.
Features
• 27 independent GPIO pins
• All programmable for Input/Output Operations
• Multiplexed functions for Port A and Port D GPIO pins
General Purpose I/O (GPIO) Register List
There are 27 GPIOs. Some are multiplexed and are used for oth er functions. Below is
the register list for all GPIOs and their respective applications.
Table 11-1: General Purpose I/O (GPIO) Registers
Address Name Default RD/WR Size Function
0x8000.0000 PADR 0 RW 8
Port A data register I/0 / Serve as a keyboard
interrupt when the interrupt is enabled.
0x8000.0001 PBDR 0 RW 8 Port B data register I/0
0x8000.0003 PDDR 0 RW 8
Port D data register I/0 - PDO can serve as
LED flasher
0x8000.0040 PADDR 0 RW 8 Port A data direction register
0x8000.0041 PBDDR 0 RW 8 Port B data direction register
0x8000.0042 ——8 Reserved
0x8000.0043 PDDDR 0 RW 8 Port D data direction register
0x8000.0083 PEDR 0 RW 3
Port E data register / Values during power-on-
reset determine width of boot memory.
0x8000.00C3 PEDDR 0 RW 3 Port E data direction register