Helge of WeatherStation writes:
After some help from wolfmanjm and CosR1, I managed to get a separate Buydisplay based GSL1680 touch panel up’n running on an Arduino Mega (1280) with only minor modifications to wolfmanjms code.
The firmware is an integrated part of the sketch. Instead of using ram, it is put in the flash memory using PROGMEM. Some, to me, special memory magic is used to read the firmware from the sketch flash (Thanks to CosR1). There might be other ways, but I haven’t investigated further. From there it is easy to write the firmware to the GSL1680 though the I2C bus. Initialization of the GSL1680 is also a bit special. It needs some special sequence of operations. I’m not sure if the code is optimal in that regard, but it seems to be stable. Linux-sunxi.org has a wiki with some info. There is even some information on the internal firmware registers here (haven’t verified if this info is correct).
I’ve forked the original wolfmanjm/GSL1680 github repo to hellange/GSL1680 and checked in the modifications needed for Arduino MEGA.