LAB #$6$: WRITING AND TESTING TIMERS

AND INTERRUPTS

OBJECTIVE

Introduce students to writing timer$-$based routines and handling interrupts in AVR assembly language

and using GPIO to visualize the results on the Curiosity Nano board.

MATERIALS

$$ Microchip AVR$64$DU$32$ Curiosity Nano evaluation kit

ASSIGNMENT

Write two programs to toggle the LED$0$ on the Curiosity Nano board repeatedly. The first program

should use a time delay generated by a timer, while the second program should utilize an Interrupt

Service Routine $($ISR$).$ The LED should be turned on for a few seconds and then off for a few seconds,

alternating continuously.

PRE$-$LAB

$1)$ Write simple instructions to turn on LED$0.$

$2)$ Write macros to load $16-$bit and $8-$bit values and store them in the data memory. Use the macros in

the programs.

$3)$ Compute the value of the counter register $($TCA$0\_$SINGLE$\_$CNT$)$ needed to generate a delay of $12$

seconds $($excluding the overhead due to instructions$).$ What is the clock frequency of the internal

OSCHF?