I am considering using a ESP8266 instead of a Raspberry Pi for a E1.31 to DMX512 bridge. I have progressed to the stage where I am able to send hand-crafted packets to the module using netcat and verifying the DMX512 output using Saleae logic analyzer. I am going to proceed with building a PCB, but in the meanwhile I want to share my code so that others who want to have a (single-ended) DMX512 output don't need to do as much trial and error as I did.
I have attached the code that I have built on top of the AT example. The tricky bit was generating the START & MAB codes by changing the IO mux. I had to modify the uart.c to support two stop bits, 0x03 seemed to be the right setting (was unable to find it documented anywhere, header file had the same bits for 1.5 and 2 stop bits?).
The code is nowhere near finished, but I hope you find it useful. I am also open to suggestions.