I believe I found a way to use just an ESP8266 module to control a set of 3D printer stepper drivers directly. This code demonstrates how.
Background:
Other projects show how to use ESP01 as a wifi-serial bridge to the arduinos, but serial is still a bottleneck and wifi uploads are impractical.
Altough ESP8266 does 160MHz at 32bits processing (versus 16MHZ 8-bit from most Arduinos) it has insufficient realtime GPIO for controlling printers.
Raspberry pi shared the realtime gpio limitation, but wallacoloo still did reprap control using DMA. Nice! https://www.youtube.com/watch?v=g4UD5MRas3E
CNLohr did a really cool WS2812 led driver (weird one-wire serial protocol) using ESP8266 I2S audio output and DMA. https://www.youtube.com/watch?v=6zqGwxqJQnw
I2S and SPI look very much alike, and SPI can control shift registers. Hey! Opportunity!
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.
