46. Differentiate between absolute and linear select decoding?
Ans:
| Absolute decoding |
Linear decoding |
| All higher address lines are defined to select the memory or I/O device |
Few higher address lines are decoded to select the memory or I/O device |
| More h/w is required to design decoding logic |
Hardware required to design
decoding logic is less |
| Higher cost for decoding circuit |
Less cost for decoding circuit |
| No multiple address |
Has a disadvantage of multiple addressing |
| Used in large systems |
Used in small systems |
47. What are the three classifications of 8086 interrupts?
Ans:
(1) Predefined interrupts
(2) User defined Hardware interrupts
(3) User defined software interrupts.
48. What is the use of 8251 chip?
Ans: Intel’s 8251A is a universal synchronous asynchronous receiver and transmitter compatible with Intel’s Processors. This may be programmed to operate in any of the serial communication modes built into it. This chip converts the parallel data into a serial stream of bits suitable for serial transmission. It is also able to receive a serial stream of bits and converts it into parallel data bytes to be read by a microprocessor.
49. What is interfacing?
Ans: An interface is a shared boundary between the devices which involves sharing information. Interfacing is the process of making two different systems communicate with each other.
50. What is meant by interrupt?
Ans: Interrupt is an external signal that causes a microprocessor to jump to a specific subroutine.
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