INTEL (Programmable Peripheral Interface). In previous lectures we have discussed how to interface I/O devices with the system bys. If an input device. The A is a programmable peripheral interface (PPI) device designed for use in Intel microcomputer systems. Its function is that of a general purposes I/O. Programmable Peripheral Interface. (Dated: pre). Features; Pinout; Block diagram; BSR mode; I/O mode; Mode 1; Mode 2.
|Published (Last):||5 June 2009|
|PDF File Size:||7.11 Mb|
|ePub File Size:||15.8 Mb|
|Price:||Free* [*Free Regsitration Required]|
This means that data can be input or output on the same eight lines PA0 – PA7.
8255A – Programmable Peripheral Interface
As an example, consider an input device connected to at port A. Mode 2 — Bi-Directional Bus. This mode is selected when D 7 bit 8255 programmable peripheral interface the Control Word Register is 1. Port Select 0 and Port Select 1.
In essence, a response from the peripheral device indicating that it has received the data output by CPU. The functional configuration of each port is programmed by the systems software. programmahle
Retrieved from ” https: Retrieved 26 July There are three basic modes of operation that can be selected by the systems pedipheral Outputs are not latched. Some of the pins of port C function as handshake lines. Retrieved 3 June From Wikipedia, the free encyclopedia.
Input Control Signal 8255 programmable peripheral interface.
Programmable Peripheral Interface and Interfacing
Mode O Basic Functional Definitions: It is an active-low signal, i. The Control Word Register can only be peripheeal into.
Used programable Group A only. The two halves of port C can be either intfrface together as an additional 8-bit port, or they can be used as individual 4-bit ports. For port B in this mode irrespective of whether is acting as an input port or output portPC0, PC1 and PC2 8255 programmable peripheral interface function as handshake lines.
This feature reduces software requirements in Control-based applications.
8255 programmable peripheral interface Views Read Edit View history. Input and Output data are latched. Interrupt logic is supported. The functional configuration of the A is programmed 8255 programmable peripheral interface the systems software so that normally no external logic is necessary to interface peripheral devices or structures.
This is required because the data only stays on the bus for one cycle. All of the output registers, including the status flip-flops, will be reset whenever the mode is changed. Each 4-bit port contains a 4-bit latch and it can be used for the controls signal outputs and status signal inputs in conjunction with ports A and B.
In this mode, the may be used to extend the system bus to a slave microprocessor peripherall to transfer data bytes to and from a floppy disk controller.
The 4-bit port is 8255 programmable peripheral interface for control and status of the 8-bit data port.
So, without latching, the outputs 8255 programmable peripheral interface become invalid as soon as the write cycle finishes. Read operation of the Control Word Register is allowed. They are normally connected to the peripneral significant bits of the address bus A0 and A1. This page was last edited on 26 Julyat