Keyboard Interfacing with PIC 16F877 - MCQs with answers
Keyboard Interfacing with PIC 16F877 - MCQs with answers1. What is the purpose of using Schmitt Trigger in the hardware circuit for key debouncing?
a. Noise Elimination
b. Improvement in Noise Immunity
c. Increase in Noise Figure
d. Reduction in Noise TemperatureView Answer / Hide Answer
2.Which lines are driven low under the software control during interfacing HEX keyboard with PIC 16F877?
ANSWER: b. Improvement in Noise Immunity
a. Scan Lines
b. Return Lines
c. Both a & b
d. None of the aboveView Answer / Hide Answer3. Which keys are encoded for scan lines with '1101' value (RB1 low) condition ?
a. 0, 4, 8, C
b. 1, 5, 9 , D
c. 2, 6, A, E
d. 3, 7, B, FView Answer / Hide Answer4. What value of 'B' should be loaded in the TRISB register if return lines (RB7 : RB4)and RB3:RB0 are supposed to be inputs and outputs respectively after the PORT B initialization?
d. 11110000 View Answer / Hide Answer