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Upgrading my Chumby 8 kernel part 7: touchscreen
- joezydeco 3y agoNicely done. Calibration was always a tricky thing on the resistive screens, as the author has seen. Normally this was all built into ts_calibrate, as part of the abandoned tslib library that AFAIK is still being used in a lot of places. The math behind ts_calibrate is covered pretty well in this old paper from Texas Instruments. It's a nice piece of work, you can convert a raw X/Y input to a finished coordinate with a simple set of multiplications and 6 coefficients. https://www.ti.com/lit/an/slyt277/slyt277.pdf https://www.ti.com/lit/an/slyt277/slyt277.pdf