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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This is required because the data only stays on the bus for one cycle.

Auth with social network: Ppi ‘s outputs are latched to hold the last data written to them. Processor reads the status of the port for this purpose In this mode, the may be used to extend the system bus to a slave microprocessor or to transfer data bytes to and from a floppy disk controller. The inputs are not latched because the CPU only has to read their current values, then store kntel data in a CPU register or memory if it needs to be referenced at a later time.

It is an active-low signal, i.

PPI PPI Programmable Peripheral Interface. – ppt video online download

If the Port interrupt is enabled, INT is activated. Interrupt logic is supported. Address lines A 1 and A 0 allow to access a data register for each port or a control register, as listed below:. Microprocessor And Its Applications. Bit 7 of Port C.


Port A can be used for bidirectional handshake data transfer. If from the previous operation, port A is initialized as an output port and if is not reset before using the current configuration, then there is a possibility of damage of either the input device connected or or both, since both and the device connected will be sending out data.

If you wish to download it, please recommend it to your friends in any social system. Required MD control word: Interrupt logic is supported.

8255A – Programmable Peripheral Interface

From Wikipedia, the free encyclopedia. Some of the pins of port C function as handshake lines. It is used to interface to the keyboard and a parallel printer ppii in PCs usually as part of an integrated chipset. Retrieved 3 June 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.

This means that data can be input or output on the same eight lines PA0 – PA7. When we intl 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.

Feedback Privacy Policy Feedback. Bidirectional Data Transfer This mode is used primarily in applications such 2855 data transfer between two computers.


D – Programmable Peripheral Interface

Retrieved from ” https: For example, if port B and upper port C have to be initialized as input ports and lower port C and port A as output ports all in mode Processor reads the port during the ISS. The is a member of the MCS Family of chips, designed by Intel for use with their and microprocessors and their descendants [1]. Share buttons are a little bit lower. The two modes are selected on the basis of the value present at the D 7 bit of the control word register.

Its contents decides the working of This mode is selected when D 7 bit of the Control Word Register is 1. Port A uses five signals from Port C as handshake signals for data transfer.

Published by Loraine Cobb Modified over 3 years ago.

Acknowledgement and handshaking signals are provided to maintain proper data flow and synchronisation between the data transmitter and receiver. Only port A can be initialized intdl this mode.

D8255 – Programmable Peripheral Interface

PC are used as handshake signals by Port A when configured in Mode 2. Inputs are not latched. The two halves of port C can be either inntel together as an additional 8-bit port, or they can be used as individual 4-bit ports.