ESP8266 Community Forum

- Mon Mar 19, 2018 4:59 am #74707 It seemed like I had gotten a connection between DTR# and RTS# while soldering last time, removing that connection still didn't stop the ESP from resetting.

I soldered wires to DTR#, RTS#, GPIO0 and RESET and made the reset circuit from the NodeMCU schematic on a breadboard using BJT's instead of the MOSFET's on my PCB. I managed to successfully program the ESP again, but only once. Now it won't program anymore, and I get the same error as I did before:

warning: espcomm_sync failed
error: espcomm_open failed
error: espcomm_upload_mem failed

Using a logic analyzer I see that the DTR# and RTS# lines don't respond when I try to program the ESP.

Back to debugging again...

- Fri Oct 19, 2018 8:14 am #78743 I picked up this project again, and there were two errors on my schematic.

First of all, VIO was left floating, so my data-lines didn't get a reference voltage, tying VIO to VDD fixed this issue.
Second of all, the CP2102N needs a voltage divider on the voltage that goes into VBUS to function properly.

Adding these two fixes made the board function as intended, and I can program the ESP-module with ease.