I see a board design named OpenEVSE_SmartLCD (https://github.com/OpenEVSE/OpenEVSE_LCD).
The description say "Experimental - not Tested adds microprocessor to remove UI load from OpenEVSE - RAPI".
On the schematic, I see four connectors (ADC, SERIAL, BUTTON, I2C).
I didn't find any firmware for it. I guess it is not publised yet.
I like the idea of moving the UI and remote API to a different processor because the EVSE firmware which is more safety critical can stay unchanged and people can experiment and be creative with the second processor.
I would configure the EVSE as a I2C master and the display as a I2C slave. The RAPI client would be connected to the display processor by UART. The EVSE would write its state in the form of short codes to the display. The display processor would be in charge of displaying it with text, color, graphics, ... The EVSE would also read the configuration from the display. So the EVSE would know when the user changed the configuration with the button or the RAPI.
Is my view similar to what was thought when the board was designed? Is there any beginning of firmware of protocol documentation available?
That was the idea, however the main contributors to the firmware did not like the idea of splitting up the code so no prototypes were ever built.