Exercises - Assembler Session 01

How-to

The intended way to work on these exercises is to make a fork of the repository, and then work on your own fork.

Solve / implement the exercises creating a new AS7 project for each of them (unless an exercise builds on the previous) - then commit at least once after each solved exercise.

git add <filenames(s) / --all>
git commit -m"Your description of what you have done"
git push

When done you are (more than) welcome to make a pull request, and I shall do my best to give you my feedback.

Now, let's get going!

Exercises

All code should be written in assembler.

1. Open Atmel Studio and on the Start Page select Download Documentation (alternatively: Help > Add and Remove Help Content)

   • Download the "AVR Instruction Set Manual" and documentation for Atmel Studio and STK600 AVR Flash MCU Start Kit.
   • Open the "AVR Instruction Set Manual" and find the description of LDI. Which registers can we load data into with LDI? Explain how this is related to the 16-bit Opcode for LDI.

2. Create a new assembler project for atmega2560 in Atmel Studio

   • How big is the program memory of the atmega2560 and how much ram does it have?
   • Replace the default code with

     ldi r16, 0b0100_0010    ; load value into register r16
     nop                     ; does nothing, but provides a place to put a breakpoint
     

   • Place a breakpoint before nop and start debugging(F5).
   • Open the Processor Status window and verify that register R16 contains the correct value.

Use the simulator in Atmel Studio 7 to verify your solutions to the following exercises.
Commit your solution at the end of each exercise.

3. Write a program that:

   • puts the decimal value 42 into register R16
   • puts the hexadecimal value 33 into register R17
   • puts the binary value 10110010 into register R18

4. Write a program that add the values 0x08 and 0xb3. Place the result in R18.

5. Write a program that calculates 34 + (55 - 12) + (3 * 33) and puts the result in r16.

Do the following exercises using the STK600 development board.
Commit your solution at the end of each exercise.

5. Hello World (or turn on a led)

   • Open the "HelloWorld" Atmel Studio project.
   • Make sure that port a and the leds are connected
   • Build the project, and program the stk600 board
   • Verify that the rightmost led got turned on

6. Try to change the program so that led 3 is turned on instead
   (commit changes when done)

7. Modify the program so that the led is turned on and off continuously.
   Hint: jump instruction is rjmp and a label looks like mylabel: