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A simple Touch Controller for resistive touch panels

🇩🇪 · Flipdot · Unknown

Deutsche Version weiter unten Flipdot member [typ.o] writes: There are more and more affordable TFT displays for Raspberry Pi coming with a resistive touch panel like this from german cheapo - supplier Pollin. I don't wanted to waste a USB connector for the touch input and also I'm planning to use the display with Python in text mode. Because I couldn't find a driver for this usecase I decided to do my own stuff. Original touch controller with USB to be replaced. Here you have touch.zip , containing the BASCOM source for the Attiny85, corresponding HEX file, quick and dirty Python test program and lcd.py module containing some VT100 shortcuts. The Attiny is set to 8 Mhz internal RC clock and brownout detection for 2,7 V. It runs nicely with the 3V3 supply of the Pi and therefore doesn't need a level shifter. Final touch controller on perfboard. The controller in the first step connects the X-resistor-plane to VCC and GND using port b3 and b1 and then measures the voltage at one terminal of the Y-plane. This A/D-input also is connected to VCC via an internal pullup resistor to