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geekhack Community => Keyboards => Topic started by: burli on Sun, 29 December 2019, 05:47:26

Title: Which firmware supports split keyboards with MCP23018 IO expander?
Post by: burli on Sun, 29 December 2019, 05:47:26

Hi,
I want to build a new split keyboard based on a Teensy 2.0 and the MCP23018 (just because I have them here), but I'm not sure which firmware has support for the MCP. Is it possible to use QMK or EasyAVR with the MCP?

Best regards
Markus

Title: Re: Which firmware supports split keyboards with MCP23018 IO expander?
Post by: Findecanor on Sun, 29 December 2019, 09:30:08

The ErgoDox uses the Teensy 2.0 and MCP23018, so every firmware that supports the ErgoDox should contain code for them in some form or other.

QMK does not have a code module with a generic API for I²C to the MCP23018. You will find it in the source code that is specific for the ErgoDox EZ, and you would probably have to copy and paste code from that and rewrite a bit for your keyboard.

Title: Re: Which firmware supports split keyboards with MCP23018 IO expander?
Post by: burli on Sun, 29 December 2019, 11:50:00

The QMK Configurator has an Ergodox EZ Option, but I don't know if it works.

https://config.qmk.fm/#/ergodox_ez/LAYOUT_ergodox

The annoying part is: I build a split Keyboard with Teensy 2.0 and MCP23018 a few years ago, but I don't remember which software I used.

Thanks for your help. I think I will find a solution.

Title: Re: Which firmware supports split keyboards with MCP23018 IO expander?
Post by: richfiles on Mon, 30 December 2019, 04:43:41

Just tagging into this thread cause the discussion on firmwares and the MCP23018 is relevant to my own interests too.

I'm curious how well (or not) any firmwares handle disconnects and reconnects with the MCP23018? I want to create something that has an I2C port that can have an accessory be detatched and reattached at will.

Title: Re: Which firmware supports split keyboards with MCP23018 IO expander?
Post by: burli on Mon, 30 December 2019, 06:55:41

I can't test it, sorry. I use the Ergodox EZ Software, but my keyboard is hard wired. I can't disconnect the MCP