DIY Chumby-lite

A simple, 1-line change to set SPI clock to 32MHz (d-oh!) now gives ~15fps across the board: Much better! Just doing ucglib justice here... :)

We have touch input! First successful test:

The chip is a TI ADS7843 clone (even table references in it's datasheet match TI's datasheet, and not it's own numbering -- had me scratching my head, until I found the TI datasheet, and then it made sense :).

Had to write driver from scratch, to use hardware SPI (otherwise there aren't enough pins). MOSI/MISO/CLK are shared with the ILI9341 display driver. While at it, added support for differential mode (code I could find used bitbanged SPI and single-ended mode). The code is currently a frakking mess, but once cleaned up, it'll be on github.

So, the $22 Digole can be replaced by a $7 generic module (running ucglib, a much nicer graphics lib, too!). Getting closer to the ~$13 mark, which makes much more sense for this device.

Edit - initial code here: https://github.com/spapadim/XPT2046

On the front of using a much cheaper display module, just got Ucglib running on Arduino for ESP:

If interested to give it a try, my port is at https://github.com/spapadim/ucglib (let me know if it worked). It also requires two simple patches to the Arduino ESP install: https://gist.github.com/spapadim/a4bc258df47f00831006. I believe that u8glib could also be ported in a similar fashion (but not interested in doing it right now).

Support for the touchscreen controller is still missing (shouldn't be hard, though).

Note: there is also a port of ucglib to NodeMCU at https://github.com/devsaurus/nodemcu-firmware/tree/dev-ucglib (which convinced me to give the Arduino port a try; thanks!!). That port strips out most fonts from the source (avoiding this was the part that took me a while to get working).

Short video showing it in action: