With some nice components from Spark Fun Electronics, I build the following setup:
- Atmel Atmega168
- Nokia 6100 display
- SD card
- DS18B20 Temperature sensor
Because of the low memory capacity of the atmega168 are the fonts for the display located at the FAT16 formatted SD-card. That works really nice
Okay, that was the introduction. The problem now is the following; since I added the temperature sensor to the system, I've some troubles with the contrast of the display. I had those troubles even before I added the sensor, but a lot less then now.
I determined the parameters of the "VOLCTR"-setting by tuning them for my system. But now, after reprogramming the system a few times, the display turns white or black and I have to adjust the contrast-parameters to get the display back on track. Another thing is that the displays contrast is a bit "flickering". Does anyone have a solution for these problems?