Description:

Intel 8255A-5 Programmable Peripheral Interface

Versions:

• 8255A Data Valid From READ: Max 250ns c78
• 8255A-5 Data Valid From READ: Max 200ns c78 Compatible with PC/XT

Note, the 8255A is not the same as the 8255. The non-A is older, The A updated.

The Intel 8255A is a general purpose programmable I/O device designed for use with Intel microprocessors. It has 24 I/O pins which may be individually programmed in 2 groups of 12 and used in 3 major modes of operation. In the first mode (MODE 0), each group of 12 I/O pins may be programmed in sets of 4 to be input or output. In MODE 1, the second mode, each group may be programmed to have 8 lines of input or output. Of the remaining 4 pins, 3 are used for handshaking and interrupt control signals. The third mode of operation (MODE 2) is a bidirectional bus mode which uses 8 lines for a bidirectional bus, and 5 lines, borrowing one from the other group, for handshaking.

• MCS-85 Compatible 8255A-5
• 24 Programmable I/O Pins
• Completely TTL Compatible
• Fully Compatible with Intel Microprocessor Families
• Improved Timing Characteristics
• Direct Bit Set/Reset Capability Easing Control Application Interface
• 40-Pin Dual In-Line Package
• Reduces System Package Count
• Improved DC Driving Capability