ESP8266 Community Forum

- Thu Feb 18, 2016 9:23 am #41372 Hi everybody,

before I did this mistake my ESP8266 ESP01 modul worked fine. But the firmware was old so I decided to update that thing. I did this with the "ESP FLASH DOWNLOAD TOOL V2.3" at the baudrate of 9600 (default for old firmware). The latest firmware (ESP8266_NONOS_SDK_V1.5.1_16_01_08 ) I downloaded from the Espressif homepage. This bin files were flashed to the respective adresses:

esp_init_data_default.bin -> 0xFC000
blank.bin -> 0xFE000
boot_v1.5.bin -> 0x00000
user1.1024.new.2.bin -> 0x01000

after that the modul work also fine, but at a baudrate of 115200. This is to fast for the SoftwareSerial of an arduino. So I changed the baudrate with the command:

AT+IPR=19200

Now nothing works. I cannot communicate to the modul, neither with 19200 nor any other baudrate, the one I get are some strange symbols and then the blue LED stays on. It doesn't react on any commands. New flash is not possible because the Flash tool doesn't have a 19200 baudrate. With other flash tools the connection failes at 19200 and other baudrates.

What can I do to rescue my little modul? Is there a chance to change the baudrate back to 115200 or 9600? or do I miss something.

thanx for help!

- Fri Feb 19, 2016 7:55 am #41442 You can choose any baudrate in the flasher, the ESP's bootloader will auto-detect the baudrate (and does not care about any setting from the AT firmware).

- Fri Feb 19, 2016 8:58 am #41450 Thanx for the reply!

I now find out that the baudrate is 9600 in the flash mode of this modul, so I was able to reflash. After reflashing the baudrate is set back to 115200.

But this is to fast for SoftwareSerial of an arduino. I want to use this modul with an arduino so I have to set it lower than 115200.

I tryed it with:
AT+IPR=19200 and AT+UART_DEF=19200,8,1,0,3

But both of them do not work. After setting the baudrate there is no communication possible. Neither at 115200 nor 19200.

Do you mean that I can change the baudrate in the tool "ESP FLASH DOWNLOAD TOOL V2.3" before flashing? I cannot find such a setting. Or is there another AT-command to change the baudrate?

- Mon Feb 22, 2016 3:32 am #41644 I solved my problem:

I have to set the baud rate to 19200 with

AT+UART_DEF=19200,8,1,0,0

to communicate with the modul via SoftwareSerial of an Arduino. The flow control has to be disabled!