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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Interrupt logic is supported. Interrupt logic is supported. From Wikipedia, the free encyclopedia. Only port A can be initialized in this mode. The two modes are selected on the basis of the value present at the D 7 bit of the control word register.

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.

8255A – Programmable Peripheral Interface

So they are shown as X Required MD control word: 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. Published by Loraine Cobb Modified over 3 years ago.

They can be configured as either as input or output ports. Requires insertion of wait states if used with a microprocessor using higher that an 8 MHz clock.


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. Feedback Privacy Policy Feedback.

8255 PPI PPI Programmable Peripheral Interface.

Retrieved 26 July The features of the mode include the following: PC are used as handshake signals by Port A when configured in Mode 2. This means that data can be input or output on the same eight lines PA0 – PA7. We think you have liked this presentation. Get code and repeat in infinite loop. The ‘s outputs are latched to hold the last data written to them.

Retrieved from ” https: There is also a Jntel port from the Processor point of view. As an example, consider an input device connected to at port A. Some of the pins of port C function as handshake lines. 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. 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.

Registration Forgot your password? Bidirectional Data Transfer This mode is used primarily in applications such as data transfer between two computers. 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 ijtel.


D – Programmable Peripheral Interface

Processor sends another byte to the port during the ISS. Address lines A 1 and A 0 allow to access a data register for each port or a control register, as listed below:. Inputs are not latched. For example, if port B and upper imtel C have to be initialized as input ports and lower port C and port A as output ports all in mode 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.

This mode is selected when D 7 bit of the Control Word Register is 1.

Intel A Programmable Peripheral Interface

About project SlidePlayer Terms of Service. Input and Output data are latched.

If an input changes while the port is being read then the result may be indeterminate. My presentations Profile Feedback Log out. Port A uses five signals from Port C as handshake signals for data transfer. It is used to interface to the keyboard and a parallel printer port in PCs usually as part of an inte, chipset.