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By timg11
#68683 I have some ESP-01 modules from a couple of years ago that I'm just getting around to using.

They look exactly like this: Image, including the silkscreen text AI-Cloud Inside

I'm communicating successfully over USB serial.
The board boots, flickers blue and has steady red LED.
When it boots, it sends the following text at 115200 baud:

Code: Select all▒l`▒▒(▒SQS▒(RQ▒)HT▒)SHHHC▒▒▒r▒9▒

Ai-Thinker Technology Co. Ltd.

ready





Every character is echoed, and LF (0x0A) causes a response (always ERROR)
CR (0x0A) is echoed, but has no other response.

AT commands are apparently not supported. Sending AT+CWLAP followed by LF resuts in
ERROR

It seems that anything followed by a LF gives a response of ERROR. All other input is echoed, but gives no other response.

Is that enough to identify which module and/or firmware I have?

What firmware should I flash to get the "normal" behavior described in the many posts in the ESP8266? E.G. AT commands, and/or using the Arduino IDE to download new code, etc?
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By QuickFix
#68714 The easiest thing is to flash the ESP with the latest firmware, like described on this page. :idea:

The only difference between a very old ESP-01 and a newer one is the amount of flash memory installed (4Mbit opposed to 8Mbit).
You can see what type of flash is installed by taking a magnifying glass and read the number on the flash: 24Q40 is 4Mbit (512kB) and 25Q80 is 8Mbit (1Mbyte).
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By timg11
#68720 Thank you, @quickfix, great article - I'm going to build the improved flashing circuit they showed.

I was able to get the AT commands to work with the existing firmware. The problem was PUTTY doesn't send CR/LF on the enter key, and the ESP-01 is very picky about case and having CR and LF just right. PUTTY offers no configuration for this aspect of the keyboard.

I found this article that shows how to fake it out with a VT-100 command sequence.
Just type ESC[20h (with ESC being the real Escape key), and it will cause PUTTY to send the proper CRLF on Enter. Then the module responded to AT commands, and I was able to get response from AT+CWLAP and others.