communication between the A and the CPU. The A is a programmable peripheral interface. (PPI) device designed for use in Intel microcomputer. PPI is a general purpose programmable I/O device designed to interface the CPU with its outside world such as ADC, DAC, keyboard etc. We can program . PPI •The INTEL is a 40 pin IC having total 24 I/O pins. consisting of 3 numbers of 8 –bit parallel I/O ports (i.e. PORT A, PORT B.

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Since the two halves of port C are independent, they may be used such that one-half is initialized as an input port while the other half is initialized as an output port. Bidirectional Data Transfer This mode is used jntel in applications such as data transfer between two computers.

To make this website work, we log user data and share it with processors. The chip select circuit connected to the Ppo pin assigns addresses to the ports of So they are shown as X Required MD control word: They can be configured as either as input or output ports. The ‘s outputs are latched to hold the last data written to them. Inputs are not latched. The two modes are selected on the basis of the value present at the D 7 bit of the control word register.

8255A – Programmable Peripheral Interface

The two halves of port C can be either used together as an additional 8-bit port, or they can be used as individual 4-bit ports. This means that data can be input or output on the same eight lines PA0 – PA7. Retrieved 3 June Ijtel and handshaking signals are provided to maintain proper data flow and synchronisation between the data transmitter and receiver.


There is also a Control port from the Processor point of view. Port A can be used for bidirectional handshake data transfer. This is required because the data only stays on the bus for one cycle.

PPI PPI Programmable Peripheral Interface. – ppt video online download

Port A uses five signals from Iintel C as handshake signals for data transfer. The is a member of the MCS Family of chips, designed by Intel for use with their and microprocessors and their descendants [1]. Processor reads the status of the port for this purpose Address lines A 1 and A 0 allow to access a data register for each port or a control register, as listed below:.

All of these chips were originally available in a pin DIL package. For example, if port B and upper port C have to be initialized as input ports itnel lower port C and port A as output ports all in mode For port B in this mode irrespective poi whether is acting as an input port or output portPC0, PC1 and PC2 pins function as handshake lines.

Processor reads the port during the ISS.

Intel – Wikipedia

Registration Forgot your password? If the Port interrupt is enabled, INT is activated. We think you have liked this presentation.


It is used to interface to the keyboard and a parallel printer port in PCs usually as part of an integrated chipset. From Wikipedia, the free encyclopedia. Processor sends another byte to the port during the ISS. If you wish to download ppk, please recommend intep to your friends in any social system. Interrupt logic is supported. When we wish to use port A or port B for handshake strobed input or output operation, we initialise that port in mode 1 port A and port B can be initilalised to operate in different modes, i.

Each line of port C PC 7 – PC 0 can be set or reset by writing a suitable value to the control word register. This mode is selected when D 7 bit of the Control Word Register is 1. Retrieved from ” https: Some of the pins of port C function as handshake lines. PC are used as handshake signals by Port B when configured in Mode 1. This page was last edited on 23 Septemberat As an example, consider an input device connected to at port A.

Only port A can be initialized in this mode. If an input changes while the port is being read then the result may be indeterminate. Interrupt logic 855 supported.