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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Acknowledgement and handshaking signals are provided to maintain proper data flow and synchronisation between the data transmitter and receiver. PC are used as handshake signals by Port B when configured in Mode 1. The chip select circuit connected to the CS pin assigns addresses to the ports of Processor sends another byte to the port during the ISS. As an ppk, consider an input device connected to at port A.

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D – Programmable Peripheral Interface

Required MD control word: It is an active-low signal, pip. This means that data can be input or output on the same eight lines PA0 – PA7. Feedback Privacy Policy Feedback. Processor reads the port during the ISS. Interrupt logic is supported. When CS Chip select is 0, is selected for communication by the processor.


This is required because the data only stays on the bus for one cycle. This interrupts the processor. 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 Port A can be used for bidirectional handshake data transfer.

It is used to interface to the keyboard and a parallel printer port in PCs usually as part of an integrated chipset. Bit 7 of Port C. We think you have liked this presentation. Interrupt logic is supported. So they are shown as X Required MD control word: Its contents decides the working of This mode is selected when D 7 bit of the Control Word Register is 1.

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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. Views Read Edit View history.

If you wish to download it, please recommend it to your friends in poi social system. About project SlidePlayer Terms of Service. Retrieved from ” https: If the Port interrupt is enabled, INT is activated. This page was last edited on 23 Septemberat Each port can be programmed to function as simply an input port or an output port. So, without latching, the ppl would become invalid as soon as the write cycle finishes.

Input and Output data are latched. PC are used as handshake signals by Port A when configured in Mode 2. Processor reads the status of the port for this purpose Inputs are not latched.


D8255 – Programmable Peripheral Interface

Microprocessor And Its Applications. 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. Registration Forgot your password? To use this website, you must agree to our Privacy Kntelincluding cookie policy.

The two modes are selected on the basis of the value present at the D 7 bit of the control word register.

Intel 8255

To make this website work, we log user data and share it with processors. Some of the pins of port C function as handshake lines. They can be configured as either as input or output ports. Get code and repeat in infinite loop. Address lines A 1 and A 0 allow to access a data register for each port or a control register, as listed below:. The two halves of port C can jntel either ppl together as an additional 8-bit port, or they can be used as individual 4-bit ports.

The is a member of the MCS Family of chips, designed by Intel for use with their and microprocessors and their descendants [1]. Auth pli social network: