Learning Objectives:

1. To develop an in-depth understanding of the operation of microprocessors and microcontrollers, machine language programming & interfacing techniques.

• An I/O interface consists of the circuitary required to connect an imput/output device to a computer system.
• On one side of the interfae have bus signals for address, data and control.
• On the other hand data path with its associated controls to transfer data between the interface and the input/output device.
• This side is called port. It can be classified as serial or parallel port.
• Parallel port transfers data simultaneously to or from the device. It uses multiple pin connector and the circuit is simple.
• Serial port transmits and receives data one bit at a time. For long distance, it is convenient and cost effective.

Solved Example: 9919-01

A memory system has a total of 8 memory chips each with 12 address lines and 4 data lines. The total size of the memory system is: (ESE Electrical 2015 Paper II)

A. 16 kbytes

B. 32 kbytes

C. 48 kbytes

D. 64 kbytes

Correct Answer: A

Solved Example: 9919-02

How many buses are connected to the 8085 microprocessor? (RRB JE IT Aug 2019 CBT II)

A. 5

B. 3

C. 2

D. 4

Correct Answer: B

Solved Example: 9919-03

To interface a slow memory, wait states are added by: (ESE Electrical 2015)

A. Extending the time of the chip select logic

B. Causing READY signal to go low

C. Causing READY signal to go high

D. By increasing the clock frequency

Correct Answer: B