I need to convert a Ethernet-connected embedded project with wireless connection.
I'm looking for a low-cost (main constraint, less than USD $15) and most open-source/-hardware possible Wi-Fi bridge module, like Vonets.
It need to behave transparent, redirecting all network frames (transport layer) to existent-and-already-stable IP stack implemented at current ETH hardware with minimal firmware modification; if possible, using existent RMII pins.
My first attempt was with ESP8266, but there's some very painful challenges:
- I couldn't just change transceiver and RJ-45 with it, because it's communication is UART-based (some module variants support SPI). To workaround that, I tried enabling PPPoS to communicate uC<->ESP8266, then sending data through ESP's built-in IP stack and forwarding it to Wi-Fi adapter and then to Internet.
However, although it's LwIP port had PPP_SUPORT #define's at source code (which seems to be added in a recent release v1.4.0 from March-2016), there's no documentation about enabling it and it's usage. Furthermore, IP forwarding also seems not be supported between virtual interface (e.g. ppp0) and "real" interface (e.g. wlan0).
- Do you suggest some other hardware to do the "Wi-Fi bridge" job? Should ESP32 (not launched yet at the moment) the solution to convert RMII signals?
- In the case of keep using ESP8266, there's another protocol or way to made it transparent?