EE 476: Laboratory 4

TV Oscilloscope


You will produce a digital oscilloscope which takes one voltage channel input and displays the resulting voltage trace on the TV.


You will probably want to review the code examples given in Video Generation with AVR.
Use this example as a basis for your program.
Before compiling, under the Project menu, choose Configure... , then in the Compiler tab. Set "Optimize for Speed", reduce the Data Stack size to 100 bytes, and turn off the "char is unsigned" option.

Build the video DAC shown below and connect it to the yellow connector on the TV using clip leads and a RCA phone jack. Make sure the TV is set to video input. Test the TV connection using the example program linked above. The power supplies on the TVs and development boards are NOT interchangable.

The scope will be AC coupled. Use the following circuit to isolate the signal source from the DC level requird by the ADC. I suggest setting Vref to Vcc for easy connection to the STK500.


A comment on this assignment from a group in Spring 2004.

Oscilloscope Lab
Timing Very Critical
Complete and Correct


Write a program in C and assembler for the microcontroller with these specifications:

When you demonstrate the program to a staff member, you should exercise all the scope functions and show that the voltage and time scales are accurately calibrated. One way to do this is to simultaneously display the output of the signal generator on your scope and on the Tek scope.

Your written lab report should include:

Copyright Cornell University Jan 2004