Practice Test Paper

Question 1

Name the C keyword that can be used to quit a function immediately.

Answer 1

return

Question 2

On what IO port do TXD and RXD pins reside?

Answer 2

PORTD

Question 3

What register is used to select the type of events that will trigger a Timer 1 Input Capture interrupt?

Answer 3

Register TCCR1A

Flags COM1A1, COM1A0, COM1B1, COM1B0

Question 4

How to force the ADC unit to start a conversion operation?

Answer 4

Set ADSC flag to 1 (register ADCCSRA)

Question 5

Determine the value of relevant registers for serial transmission at a baud rate of 2400bps, 8 data bits, one start bit, two stop bits, even parity and a system clock running at 1MHz.

Answer 5

UBRR = 1000000/(16*2400) - 1 = 25d = 19H
UBRRH = 00
UBRRL = 19H

Question 6

Assume the serial port it already set up, what needs to be done in the C function to send a character through the serial port.

Answer 6

Wait until UDRE flag = 1

Write char to UDR for transmission