27

INTERFACING INTEL 8255 PPI WITH 8051

CHAPTER OBJECTIVES

The number of I/O pins of Intel 8051 microcontroller is limited to 32 only. In some special design cases these many I/O pins might not be sufficient for the system designer. This chapter introduces a simple method to enhance the number of I/O pins by interfacing 8255, a general purpose port from Intel, with 8051. After completion of this chapter the reader would be able to:

  • Understand internal architecture and modes of 8255.
  • Interface 8255 with 8051.
  • Use 8255 in different modes through 8051.

27.1 | Introduction

From our previous discussions in Chapter 2, we know that 8051 offers four I/O ports, each of 8-bit size. This allows us to avail 32 I/O lines for external interfacing. In most ...

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