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Topic: ESP8266 SPI WiFi Shield ("nice to have") (Read 1 time) previous topic - next topic


There is a gap on the market. I couldn't find a WiFi shield with SPI connected ESP8266. It would be connected the same way like Ethernet shields and WiFi shield.

I know two libraries with standard arduino networking API (Server and Client implementation) which support SPI connection. The arduino.org's WiFi Link as used in Primo would need only a small #define modification for AVR. And today I found this WiFiSpi library and firmware.


That WiFiSpi system looks nice.

I really like that the firmware is an Arduino sketch. I think that will make it much easier for people to install the firmware using the Arduino IDE compared to the headaches of trying to flash the AT firmware.  And of course this makes it so easy to read the firmware source code and make modifications.

The availability of a shield with the firmware already installed would make it even easier. Using AT commands is attractive when the ESP8266 ships with the AT firmware already installed.

I wonder how AT vs SPI compares in terms of overhead and performance?


Jan 26, 2018, 06:48 am Last Edit: Jan 26, 2018, 09:58 am by Juraj
WiFi Link firmware is a sketch too. It has IoT configuration AP concept similar to PersWiFiManager, If the firmware connects to network, the Atmega sketch doesn't need to contain WiFi credentials. And it has Atmega sketch OTA Upload support, but it is not solved for SPI yet.

Of course, both features could by easy added to Jiri Bilek's library with WiFiManager and AVRISP (after solving the slave/master switching of SPI).

The SPI connection requires more wiring then the Serial connection. And more level shifters. So a shield would make it easy for beginners. (And the WiFi Link system requires one more connection for it's slaveReady signal.)

I trusted the statements on stackexchange about esp8266 gpio 5 V tolerance and did leave out the level shifters in my test setup. It works. The Wemos is fine. I wouldn't do that for permanent use, so the shield should have level shifting.

And reset pin of Atmega should be connected too for AVRISP.


I solved the OTA AVR ISP for WiFiSpiESP firmware and Jiri accepted the pull request into a branch.


Jan 28, 2018, 06:05 pm Last Edit: Jan 28, 2018, 06:18 pm by bilekj
I am glad you like the library.
The main goal was to substitute the buggy-by-nature serial communication with something more reliable. I tried several serial libraries using original AT firmware and at the end I am convinced the AT firmware is not suitable to make a reliable communication when the traffic is not negligible.

If you have any questions or comments, just write.

And big thanks to Juraj for (now still mysterious for me) piece of code :)


Feb 12, 2018, 09:52 am Last Edit: Feb 19, 2018, 07:14 pm by Juraj
SPI connection with level conversion and mutual reset control (the white wire is needed only for WiFi Link firmware)

more here

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