1. 8051 series of micro controllers are made by which of the following companies?
a. Atmel
b. Philips
c. None of the mentioned
d. Both of the mentioned
Answer: (d).Both of the mentioned

2. AT89C2051 has RAM of:
a. 128 bytes
b. 256 bytes
c. 64 bytes
d. 512 bytes
Answer: (b).256 bytes

3. 8051 series has how many 16 bit registers?
a. 2
b. 3
c. 1
d. 0
Answer: (a).2

4. When 8051 wakes up then 0x00 is loaded to which register?
b. SP
c. PC
d. PSW
Answer: (c).PC

5. When the micro controller executes some arithmetic operations, then the flag bits of which register are affected?
a. PSW
b. SP
d. PC
Answer: (a).PSW

6. How is the status of the carry, auxiliary carry and parity flag affected if write instruction
ADD A,#64H
a. CY=0,AC=0,P=0
b. CY=1,AC=1,P=0
c. CY=0,AC=1,P=0
d. CY=1,AC=1,P=1
Answer: (b).CY=1,AC=1,P=0

7. How are the bits of the register PSW affected if we select Bank2 of 8051?
a. PSW.5=0 and PSW.4=1
b. PSW.2=0 and PSW.3=1
c. PSW.3=1 and PSW.4=1
d. PSW.3=0 and PSW.4=1
Answer: (d).PSW.3=0 and PSW.4=1

8. If we push data onto the stack then the stack pointer
a. increases with every push
b. decreases with every push
c. none of the mentioned
d. both of the mentioned
Answer: (a).increases with every push

9. On power up, the 8051 uses which RAM locations for register R0- R7
a. 00-2F
b. 00-07
c. 00-7F
d. 00-0F
Answer: (b).00-07

10. How many bytes of bit addressable memory is present in 8051 based micro controllers?
a. 8 bytes
b. 32 bytes
c. 16 bytes
d. 128 bytes
Answer: (c).16 bytes

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