Interested to Buy Any Domain ? << Click Here >> for more details...
Design a circuit to detect when 3 and only 3 bits are set
out of 8 bits.(eg. o0101100)
- 13 Answers
- 27636 Views
- Qualcomm, RIM, I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / xyz
You fools...the question is to design a circuit
(hardware)..not writing a program.
| Is This Answer Correct ? | 31 Yes | 0 No |
Answer / esther
Add the digits and check the sum. It would imply a 3-bit
adder (max. value = 8 can be represented with three bits)
and compare the result to 011.
| Is This Answer Correct ? | 31 Yes | 2 No |
Answer / jayasuriya
Use a 8 bit parallel in serial out shift register. Use the
serial out bit to increment a counter(a 3 bit register), if
its one. After 8 shifts, compare the counter with 011b to
detect 3.
| Is This Answer Correct ? | 21 Yes | 1 No |
Answer / priya
keep the number in A reg and ratate it 8 times if carry
generates more than 3 it will indicate a non desired numer
| Is This Answer Correct ? | 12 Yes | 5 No |
Answer / aiyush
The first guy's got it write, every other answer is more
complicated than needed. Also, we cannot use a 3-input AND
like the second guy said b/c we are given 8 bits, not 3. A
3-bit adder and a comparator is all you need.
| Is This Answer Correct ? | 5 Yes | 2 No |
Answer / ravichandra
step1: start
step2: mov the byte to accumulator
step3: intialize length = 0 , count = 0
step4: rotate acc. to right through carry.
step5: if carry = 1 , increment count
step6: increment length
step7: if length < 8 , goto step3
step8: if count = 3 , (do required action)
step9: end
| Is This Answer Correct ? | 6 Yes | 4 No |
Answer / arnab kumar biswas
2 bit adder will do the trick.give 0 to one i/p.and transmit
the bits serially one by one to the other i/p.o/p of the
adder goes to latch,where it will stay until 8 bits have
come.then use comparator to compare if answer is 3 or not.
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / kalyanpa
for serially arriving stream:
use a 2 bit accumulator( S1 and S2) with outputs O1 and O2.
Final Output will be Y = ~O1 . O2
For parallel,
use combinational logic , probably priority encoder to
reduce delay.
| Is This Answer Correct ? | 0 Yes | 2 No |
Answer / gautam bhattacharya
Step 1: Store the 8 bit value in a accumulator
Step 2: Store 0x1 in a register0, initialize two counter
with 0 i.e. store zero in a reg1 and reg2.
LOOP:
Step 3: Check if AND operation between the value in
register0 and accumulator is set i.e. 1
if yes, increment reg1 and reg2
If no, increment only reg2
step 4: Left shift the value of register0 by 1
step 5: if ( reg2 >=8), exit LOOP
if ( reg1 >= 3), show that 3 bit is set
Else Go To LOOP
MOV XAR1, #Data
MOV XAR0, #0
MOV XAR2, #0
Loop:
TBIT *XAR1, #Count
BF Loop1, NTC
INR *XAR0
Loop1:
INR *XAR2
MOV AL, *XAR1
CMP AL, #0x03
BF Loop3, EQ
MOV AL, *XAR2
CMP AL, #0x80
BF Loop, NEQ
Loop3:
EXIT
| Is This Answer Correct ? | 0 Yes | 3 No |
How are macros different from functions?
Tell me why embedded system is useful?
Tell me why is it better to use multi-threading polling then single threading model?
What is the order of calling for the constructors and destructors in case of objects of inherited classes?
What is the difference between unit test and integration test?
Do you know what is priority inversion?
what are buses used for communication in embedded system?
Accessing fixed memory locations
Advantages and disadvantages of using macro and inline functions?
Please write a program to show the functionality of power-save super loop?
Can we use any function inside isr?
Can structures be passed to the functions by value?
86 Family 
