Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)
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By Lenbok
#70493 Hi,

I ordered a Sonoff S20 and want to flash new firmware on it. I have the Australian / New Zealand version and the PCB doesn't look the same as what I've seen on the web, and unfortunately it doesn't have any markings that label the pins where one would normally solder the header for uploading firmware.

This is the PCB that I have: https://imgur.com/a/FXh1h

Note that it appears to be the same as the one shown on the ITead web page for the S20 socket, seen here: http://sonoff.itead.cc/en/products/residential/s20-socket.

Can anyone tell me which pins are which? There also appear to be two different 4-pin blocks.

Cheers
User avatar
By QuickFix
#70495 The only way to be certain of which pin is which is to carefully open the WiFi-module on the board and follow the leads coming from the ESP chip.

This guy has a nice overview of the pin-out of the ESP8266 chip. :idea:
User avatar
By Lenbok
#70701 OK, thanks for that link.

So I de-soldered the mains pins (which were a pain in the rear) enough to let me remove the board and trace the pins. This let me confirm that the firmware upload header is definitely the unpopulated header nearest the button, and that the order of the pins is the same as the other S20 variants, i.e. (Gnd) (Tx) (Rx) [Vcc]. The other four-pin header looks to be non-functional (I've uploaded a photo of the underside at the original link, for reference)

It would certainly be nice if Itead had included this in the silk-screening in the first place!

I've now successfully uploaded the Sonoff-Tasmota firmware to it and it's working great.
User avatar
By QuickFix
#70774
Lenbok wrote:and that the order of the pins is the same as the other S20 variants, i.e. (Gnd) (Tx) (Rx) [Vcc]. The other four-pin header looks to be non-functional (I've uploaded a photo of the underside at the original link, for reference)

Thanks for the extra info; I'm thinking about obtaining one of these Sonoff's soon and this might be helpful. :D