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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Bidirectional Data Transfer This mode is used primarily in applications such as data transfer between two computers. Get code and repeat in infinite loop. If an input changes while the port is being read then the result may be indeterminate. 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.

To make this website work, we log user data and share it with processors. It is an active-low signal, i.

To use this website, you must agree to our Privacy Policyincluding cookie policy. This mode is selected when D 7 bit of the Control Word Register is 1.

It is used to interface to the keyboard and a parallel printer port in PCs usually as part 82555 an integrated chipset. There is also a Control port from the Processor point of view.

All of these chips were originally available in a pin DIL package. Input and Output data are latched. 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 inntel or or both, since both and the device connected will be sending out data.


Processor reads the status of the port for this purpose PC are used as handshake signals by Port B when configured in Mode 1. Its contents decides the working of This interrupts the processor.

Intel 8255

So, without latching, the outputs would become invalid as soon as the write cycle finishes. Processor reads the port during the ISS. The two modes are selected on the basis of the value present at the D 7 bit of the control word register.

Processor sends inhel byte to the port during the ISS. From Wikipedia, the free encyclopedia. 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.

Only port A can be initialized in this mode. My presentations Profile Feedback Log out. Each port can be programmed to function as simply an input port or an output port.

Intel A Programmable Peripheral Interface

Retrieved from ” https: When CS Chip select is 0, is selected for communication by the processor. Registration Forgot your password? Each port uses three lines from ort C as handshake signals.

As an example, consider an input device connected to at port A. Port A can be used for bidirectional handshake data transfer. Retrieved 3 June Microprocessor And Its Applications. We think you have liked this presentation. This means that data can be input or output on the same eight lines PA0 – PA7.

The features of the mode include the following: Interrupt logic is supported. The Intel or i Programmable Peripheral Interface PPI chip was developed and manufactured by Intel in the first half of the s for the Intel microprocessor. Inputs are not latched. Share buttons are a little bit lower. The functionality of the is now mostly embedded in larger VLSI processing chips as a sub-function. Feedback Privacy Policy Feedback.


PPI PPI Programmable Peripheral Interface. – ppt video online download

For port B in this mode irrespective of whether is acting as an input port or output portPC0, PC1 and PC2 pins function as handshake lines. Port A uses five signals from Port C as handshake signals for data transfer. If the Port interrupt is enabled, INT is activated.

About project SlidePlayer Terms of Service. Bit 7 of Port C. Some of the pins of port C function as handshake lines. By using this site, you agree to the Terms of Use and Privacy Policy. Each line of port C PC 7 – PC 0 can be set or reset by writing a suitable value to the control word register.

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Retrieved 26 July The chip select circuit connected to the CS pin assigns addresses to the ports of 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 The inputs are not latched because the CPU only has to read their current values, then store the data in a CPU register or memory if it needs to be referenced at a later time.

Published by Loraine Cobb Modified over 3 years ago.