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MICROPROCESSOR PAPER(1)

Interview Questions & Answers
Q1. What is clock frequency for 8085?
Ans :3 MHz is the maximum clock frequency for 8085.
Q2. Give an example of one address microprocessor?
ANS :8085 is a one address microprocessor.
3. Give examples for 8 / 16 / 32 bit Microprocessor?
ANS: 8-bit Processor - 8085 / Z80 / 6800; 16-bit Processor - 8086 / 68000 / Z8000; 32-bit Processor - 80386 / 80486
4. What is meant by a bus?
ANS: A bus is a group of conducting lines that carriers data, address, & control signals.
5. What are the various registers in 8085?
ANS: Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085
6. Why crystal is a preferred clock source?
ANS: Because of high stability, large Q (Quality Factor) & the frequency that doesn’t drift with aging. Crystal is used as a clock source most of the times.
7.imp_Q. In 8085 which is called as High order / Low order Register?
ANS: Flag is called as Low order register & Accumulator is called as High order Register.
8. Name 5 different addressing modes?
ANS: Immediate, Direct, Register, Register indirect, Implied addressing modes
IMP 9. In what way interrupts are classified in 8085?
ANS: In 8085 the interrupts are classified as Hardware and Software interrupts.
10. What is the difference between primary & secondary storage device?
ANS: In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: Floppy disc / Hard disk.
11. Which Stack is used in 8085?
ANS: LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be retrieved first.
12. What is Program counter?
ANS: Program counter holds the address of either the first byte of the next instruction to be fetched for execution or the address of the next byte of a multi byte instruction, which has not been completely fetched. In both the cases it gets incremented automatically one by one as the instruction bytes get fetched. Also Program register keeps the address of the next instruction.
IMP 13. What is the RST for the TRAP?
ANS: RST 4.5 is called as TRAP.
IMP 14. What are level-triggering interrupt?
ANS: RST 6.5 & RST 5.5 are level-triggering interrupts.
IMP 15. Which interrupt is not level-sensitive in 8085?
ANS: RST 7.5 is a raising edge-triggering interrupt.
IMP 16. What are Software interrupts?
ANS: RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.
17. What are the various flags used in 8085?
ANS: Sign flag, Zero flag, Auxiliary flag, Parity flag, Carry flag.
18. In 8085 name the 16 bit registers?
ANS: Stack pointer and Program counter all have 16 bits.
19. What is Stack Pointer?
ANS: Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack.
20. What happens when HLT instruction is executed in processor?
ANS: The Micro Processor enters into Halt-State and the buses are tri-stated.
21. What does Quality factor mean?
ANS: The Quality factor is also defined, as Q. So it is a number, which reflects the lossness of a circuit. Higher the Q, the lower are the losses.
22. How many interrupts are there in 8085?
ANS: There are 12 interrupts in 8085.
23. What is Tri-state logic?
ANS: Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri-state logic has a third line called enable line.
24. Which interrupt has the highest priority?
ANS: TRAP has the highest priority
25. What are Hardware interrupts?
ANS: TRAP, RST7.5, RST6.5, RST5.5, INTR
26. Can an RC circuit be used as clock source for 8085?
ANS: Yes, it can be used, if an accurate clock frequency is not required. Also, the component cost is low compared to LC or Crystal

WIRELESS COMMUNICATION TECHNOLOGIES

WIRELESS COMMUNICATION
CELLULAR COMMUNICATION GENERATIONS

• 1G(first generation)

It is the 1st generation of wireless telephony cellphones.These are the analog cellphone standards that were introduced in the 1980s and continued untill replaced by 2G digital cellphones. 1G signals were modulated to higher frequency(typically 150MHz and up).Following are the 1G mobile phone standards:

1.NMT

2.AMPS

3CDPD

• 2G (Second Generation cellular networks)

STANDARDs

GSM: It supports 8 time slotted users for each 200KHz radio channel and employed in whole world.

IS-136: It supports 3 slootted users for each 30KHz radio channel.It is mostly used in North America, South America, Australia.

PDC: It is similar to IS-136 but it is Japaneese TDMA standard.

CDMA:(IS-95) It supports 64 users that are orthogonally coded and simultanously transmitted on each 1.25MHz channel.It is mainly used in North America,Korea, Japan,China, India.

2G networks have the data transfer speed ranging from 9Kbps to 14Kbps.They are used only for voice communication & SMSing.

EVOLUTION OF 2.5G:

In the year 1999 internet was made available on cellphones under he standard called 2.5G or GPRS(General packet for radio services).It increased the data transfer speed up to 53Kbps.Now data transfer services like e-mailing, www viewing, fax were available on cellphones.

EVOLUTION OF 2.75G:

Speed of 53was not enough for voice & video content from internet.So a new standard came in 2001 which allowed data transfer with speed of upto 236Kbps.It is also called EDGE.It alowed transmission of voice and video over internet.

• 3G(Third Generation cellular network):

It's standard was presnted by ITU-T and is known as IMT-2000.It is adopted by whole world.But 3G came into act before this was established . In the year 2005 JAPAN was the first to adopted 3G.In India it came in to act in August 2008. Third generation cellular networks provide speed of upto 2Mbps.Now we can also enjoy online voice & video chatting, Live TV, online gaming,video conferencing and many more services on our 3G enabled handset.

Reasons to Stay Here

I am an electronics & communication engineering student. I have created this blog to give the tutorials on folowing aspects of WIRELESS ELECTRONICS TECHNOLOGIES

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