Microprocessor · Unit 6 · 6 hrs
Input/ Output Interfaces
Exam-focused notes for Input/ Output Interfaces (Microprocessor, CSC167): what the TU syllabus asks and how it has actually been tested, with 8 solved past questions from this unit.
What this unit covers
- Interfacing Concepts
- Ports
- Interfacing Of I/O Devices
- Interrupts In 8085
- Programmable Interrupt Controller 8259A
- Programmable Peripheral Interface 8255A
Programmable Peripheral Interface 8255A
List out the limitation of parallel communication. Explain the different operation modes of 8255A PPI. [5]
--- Parallel communication transmits multiple bits simultaneously over multiple lines, but it has the following limitations: 1. Cost: Requires more wires/lines (one for each bit), making it more expensive than serial communication. 2. Distance Limitation: S...
Full solved answer →What are different modes of parallel I/O? Differentiate between synchronous serial communication and asynchronous serial communication. [5]
Parallel I/O is commonly implemented using programmable peripheral interface chips like the 8255A. It supports the following modes: - Provides simple input/output operations for all three ports (A, B, C). - No handshaking is required. - Any port can be conf...
Full solved answer →What is the purpose of Programmable Peripheral Interface 8255A? Explain about its different ports. [5]
The 8255A is a widely used programmable parallel I/O device designed to interface a microprocessor with peripheral devices. Its main purposes are: - It can be programmed to transfer data under various conditions, ranging from simple I/O to interrupt-driven ...
Full solved answer →What are the different modes of parallel communication? Construct a control word for 8255 PPI for following configuration: .a) Port A and Port C_upper = mode 0 .b) Port B and Port C_lower = mode 0 c.) Port A and Port C_upper as input port d.) Port B and Port C_lower as output port [5]
Configuration requirements: - a) Port A and Port Cupper = Mode 0 - b) Port B and Port Clower = Mode 0 - c) Port A and Port Cupper = Input - d) Port B and Port Clower = Output Mode 0 - Simple Input/Output - Basic I/O without handshaking. - Ports A, B, Cupper...
Full solved answer →Interfacing Concepts
Differentiate between synchronous and asynchronous serial communication. Show DTE-DTE and DTE-DCE connection according to RS-232 serial communication standard. [5]
--- Feature Synchronous Asynchronous --------- Clock Sender and receiver share a common clock signal No shared clock; each character is self-timed Data framing Data is sent as a continuous stream of blocks/frames Each byte is framed with a start bit and sto...
Full solved answer →How DTE and DCE are wired using Rs-232 cables. Explain the process of double handshake I/O. [5]
--- - DTE (Data Terminal Equipment): The device that generates or consumes data, e.g., a computer or terminal. - DCE (Data Communication Equipment): The device that provides the communication channel, e.g., a modem. Pin Signal Direction Description --------...
Full solved answer →Programmable Interrupt Controller 8259A
Differentiate between vectored and non-vectored interrupts. Where and how 8259 PIC can be used to handle interrupts. [5]
--- Feature Vectored Interrupt Non-Vectored (Polled) Interrupt --------- Definition The interrupting device identifies itself and provides the address (vector) of its ISR directly to the CPU The CPU must poll each device to find out which one requested the ...
Full solved answer →List different types of ports. What are the main characteristics of programmable interrupt controller 8259A? [5]
--- Ports are the interfaces through which the CPU communicates with external devices. The main types of ports are: - Used to transfer data from peripheral devices to the CPU. - Example: Keyboard port, scanner port. - Used to transfer data from the CPU to p...
Full solved answer →Make Unit 6 stick
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