Interfacing
Interfacing
Learning Objectives:
- 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:
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?
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:
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