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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To make this website work, we log user data and share it with processors. Each line of port C PC 7 – PC 0 can be set or reset by writing a suitable value to the control word register.
8255 PPI PPI Programmable Peripheral Interface.
This means that data can be input or output on the same eight lines PA0 – PA7. 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.
Registration Forgot your password? Interrupt logic is supported. Input and Output data are latched.
Address lines A 1 and A 0 allow to access a data register for each port or a control register, as listed below:. This is required because the data only stays on the bus for one cycle. Processor reads the port during the ISS.
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. The ‘s outputs are latched to hold the last data written to them.
Auth with social network: Acknowledgement and handshaking signals are provided to maintain proper data flow and synchronisation between the data transmitter and receiver. Input and Output data are latched. Port A uses five signals from Port C as handshake signals for data transfer. Views Read Edit View history. Port A can be used for bidirectional handshake data transfer. We think you have liked this presentation.
It is an active-low signal, i. Published by Loraine Cobb Modified over 3 years ago.
PPI PPI Programmable Peripheral Interface. – ppt video online download
Intell, without latching, the outputs would become invalid as soon as the write cycle finishes. 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. There is also a Control port from the Processor point of view.
Bit 7 of Kntel C. As an example, consider an input device connected to at port A. When CS Chip select is 0, is selected for communication by the processor.
Retrieved 26 July Some of the pins of port C function as handshake lines. The functionality of the is now mostly embedded in larger VLSI processing chips as a sub-function.
The features of the mode include the following: Requires insertion of wait states if used with a microprocessor using higher that an 8 MHz clock. All of these chips were originally available in a pin DIL package.
So they are shown as X Required MD control word: Pip from ” https: If from the previous operation, port A is initialized as an output port and if is not reset before intep 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 the Port interrupt is enabled, INT is activated. Retrieved 3 June Interrupt logic is supported.
Processor reads the status of the port for this purpose 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