ESP8266 Community Forum

- Tue Aug 02, 2016 9:02 pm #51981 I bought one of the ESP-12F modules that are widely sold on eBay and Alibaba. I think that this
is probably an accurate schematic for it.



I created a small circuit board with just the module and a FTDI port to see if I could program it from the Arduino IDE.

Here is my schematic.



I am using a FTDI232 USB to UART that I bought on eBay. I am confident that I plugged it into my board in the correct orientation.

I tried several boards in the Arduino Tools>Board menu, including Generic, Sparkfun Thing, WeMOS D1 mini, Espino (ESP-12) but they all failed with "espcomm_sync failed". Any idea what I might be doing wrong, either in my circuit board or otherwise?

- Wed Aug 03, 2016 2:55 pm #52046 The schematic I posted is not correct. I had an error on the board where there was no pull-up or pull-down on GPIO-0 and I manually modified the board to pull it up thru a 10K. But then I modified the schematic for posting here and I incorrectly modified it to be a pull-down. Doh!

- Wed Aug 03, 2016 3:03 pm #52049 It is better not leaving GPIO2 floating and add a pullup there.
For GPIO0, it is of course need to be grounded temporarly at power up for new upload and leaving the pullup doing its job for execute mode.
If you still getting "espcomm_sync failed", check your power supply, some USB-TTL adaptor can not provide strong 3V, in such case, external power supply well regulated along with big capacitor such 47uF nearby the ESP would be needed.

- Wed Aug 03, 2016 3:05 pm #52050 Hi, try a 10k pull up on GPIO2 as well. Is the blue LED flashing lots?