ESP8266 Community Forum

- Thu Dec 14, 2017 12:25 pm #72499 I have a number of NodeMCU modules (V1) and have been loading small sketches on them as individual proof-of-concept code.
Now three of them no longer allow me to upload the sketch from the Arduino IDE. Browsing the interweb, I see this is a common problem, and various people claim to have resolved it by changing the usb cable, supplying more power, etc etc.
NOTE I can still upload to one of the modules.
I see this on an offending board:
error: espcomm_open failed
I turned on verbose logging in the Arduino IDE, and I see
esptool v0.4.9 - (c) 2014 Ch. Klippel <ck@atelier-klippel.de>
setting board to nodemcu
setting baudrate from 115200 to 115200
setting port from COM1 to COM3
setting address from 0x00000000 to 0x00000000

I opened the serial monitor, and pressed the reset button. I saw a bunch of jibberish, I tried various baud rates, and found that on 74880, the NodeMCU was saying:
"
ets Jan 8 2013,rst cause:2, boot mode:(7,7)

waiting for host"
I changed back to the nodeMCU which is still accepting uploads, and without trying to upload
I pressed the reset button. I saw this:
ets Jan 8 2013,rst cause:2, boot mode:(3,6)

load 0x4010f000, len 1384, room 16
tail 8
chksum 0x2d
csum 0x2d
v09f0c112
~ld
⸮
Note that the IDE upload speed options dont include 74880
I uploaded my WiFi sketch, it succeeded, and the serial monitor showed jibberish at 74880, however setting it to 115200,and reset, I saw jibberish followed by my message. Back to 74880, reset, I saw the linux messages, followed by jibberish (my message).

For the past several months, I have had everything set to 115200, and all has been well, now suddenly we have this strange 74880 - Does anyone have any ideas? I'm beginning to think I need to re-install the firmware, but if I cant load a sketch, I suspect I wont be able to change the firmware

- Fri Dec 15, 2017 7:50 am #72508 Following on from this, I installed the Arduino IDE on a new machine (my Surface) and copied the small sketches over. When I plugged in the board on the usb cable, it immediately installed the ftdi driver. I checked and its the latest. I set the upload speed to 115200, and tried to upload. Same result.
It certainly looks like the NodeMCU has decided to change its baud rate, which is why I cant upload to it at 115200. If I could set the Arduino IDE / esptool to 74880, I would be able to check. Note that in each of my test sketches, I set Serial.begin(115200) and the NodeMCUs that were allowing uploads, but now are not, are still outputting my messages at 115200.

- Fri Dec 15, 2017 11:09 am #72511 Uninstalled the driver for the CP2102, and deleted the device. Rebooted the PC, allowed it to reinstall the device, downloaded the latest driver from Silicon Labs. Still no joy. Given that 2 boards are giving the error espcomm_open failed, One board was failing , but is now accepting uploads, and a forth is still working, it does seem to be an issue with the nodeMCU: Does anyone know how the espcomm code negotiates the baud rate with the NodeMCU?