I am working with a DS1820 temperature sensor in assembly (everything working ok there).
I trying to display the temperature over video on one of the security cameras at my home. I am using an example I got from the net here:http://www.circuitcellar.com/avr2004/wentries/A3754.zip.
Just testing the video overlay code without any modifications except that I adapted the code to an attiny2313 (changed delays & usart settings) it is working.
The problem is that the brightness of the text is good for about two seconds, then starts to slowly fade until you can't see it anymore. I have played with the 120 ohm resistor, however it only makes a difference at startup, then the text slowly begins to fade away.
I have used the default crystal (10MHz) and tried the 14.318 MHz crystal and also a 20Mhz crystal, ALL ARE WORKING with the same problem, fading text. The higher frequencies give less flickering in the video.
Just wondering if anyone has an idea what the problem is? I have included the circuit here, the code is in the link above.