The document provides an overview of the 8255A programmable peripheral interface (PPI) and the 8259A interrupt controller. It details the PPI's block diagram, its different I/O modes, and its role in interfacing with devices like keyboards and printers in PCs. Additionally, it outlines various operational modes of the 8255A which include basic I/O, strobed I/O, and bi-directional I/O.

1. Adarsh Patel

2. 8255A : PPI 8259A : PIC 2
- Introduction to 8255A
 Block diagram
 Different I/O modes
- Introduction to 8259A
 Block diagram
 Different interrupt modes
:: Reference ::
Microprocessor Architecture, Programming, and Applications
With the 8085 - By Ramesh Gaonkar
http://www.slideshare.net/anuja1310/interfacing-8255

3. 8255A : PPI 8259A : PIC 3
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 It is used to interface to the keyboard and a parallel printer
port in PCs (usually as part of an integrated chipset).
 PPI has 24 pins for I/O that are programmable in groups of
12 pins and has three distinct modes of operation.
Controls
Group A
Port A
Port C Upper (C7
to C4)
Group B
Port C lower (C3
to C0)
Port B

4. 8255A : PPI 8259A : PIC 4
MODES
BSR BIT SET-RESET I/O MODE
MODE 0 Basic I/O
Mode
MODE 1 : Strobed I/O
Mode
MODE 2 : Strobed
Bi-directional I/O

5. 58255A : PPI 8259A : PIC

6. 68255A : PPI 8259A : PIC
• Byte A : I / O mode
• Byte B : BSR (Bit Set / reset) Modes

7. 8255A : PPI 8259A : PIC 7
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12. 128255A : PPI 8259A : PIC

13. 138255A : PPI 8259A : PIC

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