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mattdibi / redox-keyboard

Ergonomic split mechanical keyboard
MIT License
1.79k stars 167 forks source link

Question about RGB and i2c #80

Closed renkam closed 3 years ago

renkam commented 3 years ago

If I understand everything correctly when LED underglow is not used, then both sides communicate over i2c. If underglow is used then serial connection is used instead i2c.

On schematic pdf (https://github.com/mattdibi/redox-keyboard/blob/master/redox/pcb/Redox-schematic.pdf) there is rgb_data output. Is this output uses i2c? Is it possible to use oled display with rgb underglow in this configuration?

mattdibi commented 3 years ago

Hi,

A clarification. QMK allows for two type of communication for split keyboards: serial and I2C. I2C needs two data wires (SDA, SCL) to work while serial only one. To drive the LEDs we need that extra wire and thus if you use the I2C communication you can't connect the LED underglow.

The rgb_data output is a single data output and thus cannot be configured to drive I2C-based OLED displays (because again they need 2 data lines).

Hope this helps.

renkam commented 3 years ago

This helps. If I understand correctly (again :smile:), I can use RX1/PD2 for serial and then I have 2/PD1 and 3/PD0 free to use for OLED display. Also I have still free 5/PC6 and A3/PF4 for rotary encoder.

Please correct me if I am wrong.

mattdibi commented 3 years ago

Technically yes. But you would need to modify the Redox PCBs as these pins are already used (PD1 and PD0 are routed to the TRRS connector).

renkam commented 3 years ago

Understood. Thanks!