The 8255 has 24 io pins divided into 3 groups of 8 pins each. The 8255a is a general purpose programmable io device designed for use with intel microprocessors. The mode format for io as shown in figure the control word for both mode is same. Programmable peripheral interface ppi 8255 8255 is a general purpose programmable device used for data transfer between processor and io devices. In most of the cases, the pio 8255 is used for interfacing the analog to digital converters with microprocessor. The 8255 is a member of the mcs85 family of chips, designed by intel for use with their 8085 and 8086 microprocessors and. Microprocessor and interfacing pdf notes mpi notes pdf. View notes interfacing 8255 with 8051 from electrical ee1234 at engineering college. Now we will see how can we tell microprocessor that which port of 8255.
Interfacing 8086 with 8255 pdf intel a programmable peripheral interface learn microprocessor in simple sets, interrupts, addressing modes, multiprocessor configuration. A, b, and c the individual ports can be programmed to be input or output. It is a general purpose programmable io device which may be used with many different microprocessors. Intel programmable peripheal interface,alldatasheet, datasheet, datasheet search site for electronic. Table 1 describes the input and output ports of the a8255. Programmable peripheral interface the 8255a is a general purpose programmable io device designed for use with intel microprocessors. Control word format for 8255a electronics engineering. Interfacing 8255 with 8086 microprocessor interfacing. The 8255 ic is a programmable peripheral interface which is used to interface the microprocessor with other computer devices inputoutput devices. Lecture 2 8255 programmable peripheral interface ppi 1 references chapter. Requires insertion of wait states if used with a microprocessor using higher. The 82c55a is pin compatible with the nmos 8255a and 8255a5.
Lower order of 8bit address a0a7 is separated from ad0ad7 using address latchbuffer ex. Ppi 8255 is a general purpose programmable io device designed to interface the cpu with its outside world such as adc, dac, keyboard etc. This mode affects only one bit of port c at a time because, as user set the bit, it remains set until. These ports are further divided in to two groups a and b. Its function is that of a general purposes io component to interface peripheral equipment to the microcomputer system bush. The i8255 was also used with the intel 8085 and intel 8086 and their descendants and found wide applicability in digital. Design and simulation of 8255 programmable peripheral interface. The parallel inputoutput port chip 8255 is also called as programmable peripheral input output port. It has 24 io programmable pins like pa,pb,pc 38 pins. It is used to interface to the keyboard and a parallel printer port in pcs usually as part of an integrated chipset. It consists of three 8bit bidirectional io ports i. Microprocessor and interfacing notes pdf mpi pdf notes book starts with the topics vector interrupt table, timing diagram, interrupt structure of 8086.
The device has three 8bit ports port a, port b and port c. What is 8255 programmable peripheral interface ppi. Tugas makalah mata kuliah arsitektur komputer di kampus sttpln jakarta. The intent is to provide a complete io interface in one chip. Modes of operation of 8255 ppi programmable peripheral.
Singlebit, 4bit, and bytewide input and output ports level sensitive inputs latched outputs strobed inputs or outputs strobed bidirectional input. Introduction to 8255 ppi the intel 8255a is a highperformance, general purpose programmable io device is designed for use with all intel and most other microprocessors the 82c55 is a popular interfacing component, that can interface any ttlcompatible io device to. Here you can download the free lecture notes of microprocessor and interfacing pdf notes mpi notes pdf materials with multiple file links to download. The groups are denoted by port a, port b and port c respectively. Here we see how can we use programmable peripheral interface ppi ic 8255 for data transfer. As we know programmable peripheral interface ppi ic 8255 is used to interface input and output device with microprocessor. Cmos programmable peripheral interface datasheet the 82c55a is a high performance cmos version of the industry standard 8255a and is manufactured using a selfaligned silicon gate cmos process scaled saji iv. Every one of the ports can be configured as either an input port or an output port. How many ports are there in 8255 and what are they.
It consists of three 8bit bidirectional io ports 24io lines that can be configured to meet different system io needs. It is used with many microprocessors and microcontrollers for various purposes. Multiple choice questions and answers mcq on the 8255 programmable peripheral interface ppi with 4 choices, correct answer and explanation. Description the intel 82c55a is a general purpose programmable io device which may be used with many different microprocessors. Bsr mode bit set reset mode io mode inputoutput mode. It is a tristate 8bit buffer, which is used to interface the microprocessor to the system data bus. The 8255 provides 24 parallel inputoutput lines with a variety of programmable operating modes. The 82c55a is a programmable peripheral interface device designed for. The mode in which the 8255 works defines the functioning of it in that mode. The 8255 programmable peripheral interface intel has developed several peripheral controller chips designed to support the 80x86 processor family. The 82c55a is a programmable peripheral interface device designed for use in intel microcomputer systems. Electrodiction offers a complete channel of guidance on topics such as analog electronics, microprocessors, digital electronics and circuit theory.
The intels 8255 is designed for use with intels 8bit, 16bit and higher capability microprocessors. Ppi 8255 is a general purpose programmable io device designed to interface the cpu with its outside world such as. Programmable peripheral interface 8255 geeksforgeeks. This section we will only emphasize the interfacing techniques of analog to digital converters with 8255. Architecture, pin diagram, operational modes and control word format. We already discussed in my previous post about programmable peripheral interface ppi ic 8255 and operational modes of 8255 ppi ic. Lokanath reddy 2 8086 memory and digital interfacing 8086 addressing and address decoding interfacing ram, rom, eprom to 8086 8255 programmable peripheral interface. It is also called as programmable peripheral inputoutput port. Suresh bojja department of ece 8255 ppi programmable peripheral interface open box education. The 82c55a is a high performance cmos version of the industry standard 8255a. We can program it according to the given condition. The intel 8255 or i8255 programmable peripheral interface ppi chip was developed and manufactured by intel in the first half of the 1970s for the intel 8080 microprocessor.
Reset out signal from 8085 is connected to the reset signal of the 8255. The 8255a programmable peripheral interface ppi implements a generalpurpose io. Data is transmitted or received by the buffer as per the instructions by the cpu. The separated address lines a0a7 are connected to a0a7 input pins of 8255 and the separated data bus d0d7 are connected to d0d7 pins of 8255. Part, manufacturer, description, pdf, samples, ordering. The individual ports can be programmed to be input or output.
Its function is that of a general purpose io component to interface peripheral equipment to the microcomputer system bus. Now let us discuss the functional description of the pins in 8255a. The 8255a programmable peripheral interface ppi implements a general. Show the control word format for io mode operation of ppi 8255. They can also be changed dynamically, in contrast to. Here rd and wr signals are activated when iom signal is high, indicating io bus cycle.810 397 1367 1290 567 1484 1021 1454 459 1184 794 815 628 176 1307 637 1398 367 1244 554 180 501 1261 511 51 1322 266 152 264 998 1399 1183