8255 PPI CHIP ARCHITECTURE PDF

input device with the output device or vice-versa. In order to make it simpler, Intel has designed A chip to interface I/O devices. The Intel A is a general. A Programmable Peripheral Interface in Microprocessor – A Programmable Peripheral The following figure shows the architecture of A −. The (or i) programmable peripheral interface (PPI) chip was developed and manufactured by Intel The PPI chip Architecture.

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The 4-bit port is used for control and status of the 8-bit data port. This 3-stable bi-directional 8-bit buffer is used to interface the A to the systems data bus.

8255A – Programmable Peripheral Interface

Digital Logic Design Interview Questions. Microprocessor And Its Applications. The Control Word Register can only be written into. Read operation of the Control Word Register is allowed.

Group A and Group B Controls: All Mask flip-flops are automatically reset during mode selection and device reset. Embedded Systems Archhitecture Tests. This functional configuration provides simple input operations for each of the three ports. 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.

8255 Programmable Peripheral Interface

A “high” on this input initializes the control register to 9Bh and all ports A, B, C are set to the input mode.

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Address lines A 1 and A 0 allow to access a data register for each port or a control register, as listed below:. Bit definitions of the control register to modify single bits of port C.

Explain with block diagram working of PPI.

The input pins for the control logic section are described ardhitecture. This feature reduces software requirements in Control-based applications. Jobs in Meghalaya Jobs in Shillong.

During the execution of the systems program any of the other modes may be selected using a single output Instruction. The functional configuration of each port is programmed by the systems software. Digital Communication Interview Questions. They are normally connected to the least significant bits of the address bus A0 and A1. WR Write Input Whenever this input line is a logical 0 and the CS input is a logical 0, data is written to the from the system data bus A0 – A1 Address Inputs The logical combination of these two input lines determines which internal register of the data is written to or read from.

Each 4-bit port contains a 4-bit latch and it can be used for the controls signal outputs cchip status signal inputs in conjunction with ports A and B. Output data from the CPU to the ports or control register, and input data to the CPU from the ports or status register are all passed through the buffer.

Acknowledgement and handshaking signals are provided to maintain proper data flow and synchronisation between the data transmitter and receiver.

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Retrieved 26 82555 Memory Access Assembler Tutorial for Beginner How to design your resume? Port C can be spitted into two parts and each can architecturre used as control signals for ports A and B in the handshake mode. Embedded C Interview Questions. Mode O Basic Functional Definitions: For instance; Group B can be programmed in Mode 0 to monitor simple switch closing or display computational results, Group A could be programmed in Mode 1 to monitor a keyboard or tape reader on an interrupt-driven basis.

As an example, consider an input ppi connected to at port A. CS Chip Select Input.

Intel A Programmable Peripheral Interface

Digital Electronics Practice Tests. A “low” on this input pin enables the communcation between the and the CPU. This port can be divided into two 4-bit ports under the mode control.

You get question papers, syllabus, subject analysis, answers – all in one app. Outputs are not latched.

A “low” on this input pin enables to send the data or status information to the CPU on the data bus. So, without latching, the outputs would archtiecture invalid as soon as the write cycle finishes. Mode 2 — Bi-Directional Bus.