ESP8266-01: The module does not respond to AT commands when connected to 3.3V

Hello

I bought a black ESP8266-01 module from the Chinese some time ago and I wanted to use it to collect information wirelessly from the DS temperature sensor. I connected the pins according to the schematic, but since I didn't have a meter at hand I mistakenly chose the wrong goldpin on the USB-RS232 adapter and got 5V for a while. I thought that I had sent him to "the land of the eternal hunt" at the start. I connected correctly to 3.3V and to my surprise the module allows firmware upload (blue LED blinks merrily). The upload is successful but although I have tried various firmware versions it is mostly ESP silent on RS232 or the blue LED blinks like crazy and rubbish (on all standard speeds) or errors are sent. These are the ones I have managed to capture:

Quote:

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

load 0x40100000, len 25576, room 16
tail 8
chksum 0x6b
load 0x3ffe8000, len 2196, room 0
tail 4
chksum 0x3d
load 0x3ffe8894, len 8, room 4
tail 4
chksum 0x1e
csum 0x1e
rf_cal[0] !=0x05,is 0xFF

Quote:

epc1=0x40240558, epc2=0x000000, epc3=0x000000, excvaddr=0x000000, depc=0x000000
Fatal exception (0):

Quote:

epc1=0x40210c00, epc2=0x00000000, epc3=0x000000, excvaddr=0x000000, depc=0x000000
Fatal exception (0):

No AT commands work.
Am I doing something wrong, or did I just break it?

does it communicate with the flashing tool?

It communicates with the flashing tool. Even with several tools. I upload different firmware and the program does not report errors but unfortunately ESP does not respond to AT commands and does not communicate with ESPlorer for NodeMcu firmware

Show how you have the module connected.
CH-PD, GPIO0, RESET, VCC should be together.

piotr411 wrote:

Show how you have the module connected.
CH-PD, GPIO0, RESET, VCC should be together.

I had RESET to GND. After connecting it under VCC on the 74880 speed I get:

Quote:

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

load 0x40100000, len 25576, room 16
tail 8
chksum 0x6b
load 0x3ffe8000, len 2196, room 0
tail 4
chksum 0x3d
load 0x3ffe8894, len 8, room 4
tail 4
chksum 0x1e
csum 0x1e
rf_cal[0] !=0x05,is 0xFF

Here Link is described probably the same problem and a solution given. Might be worth checking out...

After installing the firmware from this page I get a very similar error on the same frequency:

Quote:

,rst cause:2, boot mode:( 3,6)

load 0x40100000, len 31900, room 16
tail 12
chksum 0x49
ho 0 tail 12 room 4
load 0x3ffe8000, len 3064, room 12
tail 12
chksum 0x74
ho 0 tail 12 room 4
load 0x3ffe8bf8, len 8, room 12
tail 8
chksum 0x12
csum 0x12
R

And have you tried programming this module under Arduino? You could then rule out whether it's a problem with the NodeMcu firmware itself.

Physically connect to the Arduino and only program or just use the Arduino IDE?

Use an Arduino IDE with ESP8266 support installed. Connect the ESP module via a USB-RS232 adapter and program it like a regular Arduino.
You can try uploading a ready-made program, e.g. WiFiScan, and see if it throws something up on the console.

The esp programming does not reach the end. I hear the familiar USB disconnect sound in the speakers. I think I have something faulty though....

Maybe the FLASH memory has been damaged.
I also once inadvertently misplaced a jumper in the programmer and connected the ESP-01 to 5V. The memory burnt out and the ESP8266 chip is still working today

Perhaps it could be replaced....