EE 476: Laboratory 1

Introduction to the lab hardware/software.


This assignment introduces you to the software and hardware development tools you will use this semester to work with the Atmel AT90-series microcontroller chips.

modified Feb 2, 1999 (in red below)


The hardware you will be using to support the AT90-series is the Flash MCU evaluation board, a small board providing:

A small power supply provides power to the development board.

Most lab exercises will involve using a prototype board. A separate power supply will be used for powering the prototype board.


Software you will use consists of:


  1. Make sure the evaluation board is connected to power and to the PC as specified in the Evaluation Board description. Turn on the power supply with the little blue switch on the board. The LED D144 should come on and the red-yellow-green LEDs should come on, but extinguish again within a second. For this first lab, there should be jumpers from PortB to the LED connector and from PortD to the switch connector. Ask your instructor for help if these are not installed.

  2. Make a subdirectory for your group in the c:\users directory. Be sure to put all your files there and to back up daily to floppy. Random user files found outside the c:\users directory may be erased.

  3. The software you will use can be found in the Start menu under AVR Tools.

  4. You can use the AVR assembler source-editor window to construct a text file of assembler code. For now, paste this source code into the editor window. Be sure that you have placed the header information in your directory and modify the include line in the assembler source so that the assembler can find it.

  5. Click on the assemble button on the assembler menu. A message window will open to tell you if there are errors in the code. If there are errors, The open the listing file to see where they are.

  6. Open AvrProg, but note that the prgram will fail to open if the target board is not attached and turned on. Use the Browse button to locate the hex file you have just produced with the assembler, then click the "Program Flash" button. The code should download and start to run. Pushing ARESET on the development board will restart the program on the target mcu. This demo program should cause the LEDs to count up at 10 per second.


All timing must be done with interrupt-driven hardware timers and not with software wait-loops. Each of the following modifications should be saved separately for demonstration.

  1. For the program you were given, check the clock rate by timing enough cycles of 0-to-255 to show a difference from the rate you would calculate from the interrupt time. Probably six cycles is enough.

  2. Modify the program you were given to count up at one count per second only when switch0 is pressed and held. The LED displayed count should stop counting when the switch is not pressed.

  3. Modify the program to cause the LEDs 0-6 to count up in binary from 00H to 07FH and back down to 00H again, and repeat indefinitely. The count rate should be 10 per second. LED 7 should blink at a rate of one per second.
Be prepared to demo the programs you wrote to your TA in lab.

Your written lab report should include:

December 1998 Cornell university 1999