91. What is a data amplifier?
Ans: Transceivers are the bi-directional buffers are some times they are called as data amplifiers. They are required to separate the valid data from the time multiplexed address data signal. They are controlled by 2 signals i.e DEN & DT/R.
92. What is status flag bit?
Ans: The flag register reflects the results of logical and arithmetic instructions. The flag register digits D0, D2, D4, D6, D7 and D11 are modified according to the result of the execution of logical and arithmetic instruction. These are called as status flag bits.
93. What is a control flag?
Ans: The bits D8 and D9 namely, trap flag (TF) and interrupt flag (IF) bits, are used for controlling machine operation and thus they are called control flags.
94. What is instruction pipelining?
Ans: Major function of the bus unit is to fetch instruction bytes from the memory. In fact, the instructions are fetched in advance and stored in a queue to enable faster execution of the instructions. This concept is known as instruction pipelining.
95. Compare Microprocessor and Microcontroller.
program counter, clock timing
circuit and interrupt circuit.
|Microcontroller contains the circuitry
of microprocessor and in addition it
has built- in ROM, RAM, I/O
devices, timers and counters.
|It has many instructions to
move data between memory
|It has one or two instructions to move
data between memory and CPU.
|It has one or two bit handling
|It has many bit handling instructions.|
|Access times for memory and I/O
devices are more.
|Less access times for built-in memory
and I/O devices.
|Microprocessor based system
requires more hardware.
|Microcontroller based system requires
less hardware reducing PCB size and
increasing the reliability.