Is my nodemcu dead ?

[matejjj]

Hello. I probably short circuted my nodemcu, with ground pin connected and 5V wire touching either 3V or ground pin. I am not able to connect to it now. Hovewer, my PC still recognize it when connected and also led is blinking as usually while booting. I am still able to erase and write flash with esp tool, but I cant connect to it with putty. Nothing is send to my node mcu via serial port. I get some chars at reset, but they are not readable. It look like my baudrate is wrong, but I am sure my baud rate is correct (115200). Also, after clean flash, there is no AP created on boot. I think its dead, but can I somehow test it or even repair it ?

[Roberthh]

Erasing and writing requires two side communication with the device. So it's not completely dead. At least the USB/UART chip and the CPU are working. Maybe the flash chip is damaged. The boot message is sent at 74880 Baud. If you use that baud rate, you can see what's happening.

[matejjj]

This is the output. What does this mean ?

https://ctrlv.sk/shots/2021/02/11/UJU8.png

[Roberthh]

Not a lot. It just shows that the bootloader starts and attempts to load code to the flash. The first load's parameters are fine, but the result and the following load's address and length value are odd, indicating trouble. So the flash chip or it's interface seem corrupted. You can replace it. It is not expensive (~1€) and not too complicated to replace. But it might not be worth the effort with board prices between ~3€ and ~6€.

This is what I see:

Code: Select all

 ets Jan  8 2013,rst cause:2, boot mode:(3,6)

load 0x40100000, len 30764, room 16 
tail 12
chksum 0x16
ho 0 tail 12 room 4
load 0x3ffe8000, len 1012, room 12 
tail 8
chksum 0x48
load 0x3ffe8400, len 1080, room 0 
tail 8
chksum 0x9f
csum 0x9f
rf cal sector: 1019
freq trace enable 0
rf[112] : 00
rf[113] : 00
rf[114] : 01

[matejjj]

Ok, thank you