Noob AMB82-Mini (RTL8735B) Upload Fail

[BadBetta]

I am probably missing something simple, but I cannot upload the Arduino blink skech to an amb82-mini. I am using a clean, updated install of Ubuntu on a Celeron platform. The board appears to connect at ttyS4, with settings Erase then Upload, Auto Flash Enabled, Standard Lib Disabled, Upload Speed 2000000. The sketch will compile, but then it fails to connect, error messages including:
Ping fail
NOR flashloader loading fail
Uart boot fail
Upload fail
.ping fail

Nothing appears on the serial monitor.

Please help this lost noob…
Thanks!

[dakamaster]

Hi @BadBetta

Welcome to AmebaIoT Forum!

Please refer to our AmebaIoT Forum FAQ for help:

@Pammy

How to enter download mode with AMB82-Mini?

For more details, you can also read the Getting Start manual on our official website.

Alternatively, you also can join our community Facebook ZH/EN for help.

Thanks and happy coding!

[BadBetta]

Hello!

Thank you for your response.

I still cannot enter download mode with the AMB82-Mini. I am doing the following:

1. Plug Board in using microusb (right side connection near red led)
   - All leds (RG&B) flash quickly and then stay lit
2. Open Arduino Blink sketch & Arduino Serial Monitor (blank)
3. Press and hold Uart Download button (left side button near blue led)
4. Press and release Reset Button (right side button near red led)
   - The green led turns off, the red and blue leds stay on
5. Release Uart Download button
   - Nothing shows on the Serial Monitor
   - Upload fails

• Pressing Reset again causes the blue & green leds to flash quickly (red stays on) and then all leds stay on

Please help. I have tried 3 different boards and many operating systems (Ubuntu, Debian, Kali, Raspbian, Windows 10 & 11) without success. I would like to be able to use this board in my current project, but it seems I may need to use something else (esp32?) since I cannot get this to work.

Also, I do not have access to social media in my current work environment, so I appreciate your help using the forum.

Thank you,
JR

[dakamaster]

Hi @BadBetta,

Thanks for providing more details regarding your questions.

After step 2 , you can follow the video instruction here to enter Download Mode on AMB82.

After entering the UART Download mode, you should be able to see the log in your serial monitor indicating your board is able to receive an uploaded image:

Alternatively, you can try with another USB cable to prevent connectivity issues.

If you are still not able to enter the download mode after trying the above methods, please provide the log message after step 1 here for issue assessment.

Thanks!

[luiscat95]

Hi

, friends, I hope you can help me, I also have this problem, I bought 02 AMB82 board, and I have the same problem, I cannot load any code and carry out the uart steps, it also recognizes the CH340 cable and the port, when it comes to perform the download also follow the steps of the buttons and I get this image I hope you can help me, thank you very much

[Pammy]

Hi @luiscat95,

you may refer to this reply, Noob AMB82-Mini (RTL8735B) Upload Fail - #4 by dakamaster. Thank you

[Mel]

Hi. I had the same problem as in above post with upload fail…ping retry fail…with new board today and blink test sketch. I made many tries on the recommended use of the boot and reset button sequence with no success. Finally I just held down the boot button while it uploaded, …dot sequence. I did nothing with the reset button and it booted up…upload success. Maybe change instructions if this is universal?

[Kelvin_Huang]

Hi @Mel,

There is no change in instructions. Can you double check one thing, when you go into serial monitor, press the two buttons at the side of AMB82-mini, screenshot what you see there.

Thank you.

[Mel]

Hi. Here is what I see after upload, then when press both at same time, Blink sketch stops:

After I changed blink time and did the one boot button hold upload again, then pressed both:

Is it a board/bootloader defect then or?
Cheers
Mel

[Mel]

Hi Again. After a few more upload attempts after making sketch changes, the single button method no longer worked either; I just get variations of this ping fail, as others have:

Serial monitor shows things like this, in this case when I get same fail, when trying to upload object detection example:

Currently no way I see to upload?
Cheers
Mel

[Kelvin_Huang]

Hi @Mel,

For the first picture, this shows that you are not in upload mode (which is pressing the two buttons) when you click on the compile button.

For the second picture, please change the serial monitor baud rate from 9600 to 115200 at the middle right side of the second picture.

Rule of thumb is

1. Go to serial monitor, set to 115200 baud rate. Press the two buttons at the side of AMB82-Mini.
2. You should see this picture.
   
   

This is a sign that you are in upload mode and you can compile and upload your code.

Thanks.

[SuperSonic72]

To everyone experiencing the communication issue above - after hours of fighting with the board, I’ve come to the following result: First, the sequence to enter upload mode is pressing Reset (the button next to the red LED), then press Download, then release Reset, and then release Download. Second, the cable is very important; after replacing several cables, I found one that establishes good communication and manages to upload the program without errors. I don’t know why this is, but I had a similar issue with ESP32, probably due to the driver; maybe Realtek should provide a verified cable with the kit. Good luck to all enthusiasts!

[pchatty]

Hi,

I was facing the same issue. I fixed it by downloading the right USB driver from CH341SER.ZIP - NanjingQinhengMicroelectronics and confirming if the device shows in device manager (previously it did not). Rest, followed the steps as discussed by @dakamaster. Hope this helps!

BR

[Mel]

I am again experiencing upload problem. I have a number of working boards so am familiar with the upload process but a new one on first connection to PC has both LEDs, the blue and red lit all the time after power applied, not just when in upload mode. Hence doing the above button upload sequence makes no change. The PC recognizes the com port; I also tried other working USB cable. Deepseek suggests erasing possible corrupted flash, but can’t upload to erase. Finally DS suggestion of defective or mis-soldered NOR flash and only option is to replace board. Here is verbose:

Sketch uses 9580544 bytes (57%) of program storage space. Maximum is 16777216 bytes.
“C:\Users\Mel\AppData\Local\Arduino15\packages\realtek\tools\ameba_pro2_tools\1.4.5/image_windows.exe” “C:\Users\Mel\AppData\Local\Arduino15\packages\realtek\tools\ameba_pro2_tools\1.4.5” “COM3” “{board}” “Disable” “Enable” “2000000” “uartfwburn.exe” “Auto_Flash_Pro2_V3.3_win.exe” “0x60000” “0x460000” “0x530000”
Enter Flash Mode!
Start Erase Flash
Erasing.Create File Error

uart COM3 open fail

NOR flashloader loading fail

nop fail
End Erase Flash

[M-ichae-l]

@Mel

lit

Sorry to hear your bad experience, the case is very rare. In my opinion, it is more sound like a HW failure. But lets do some testing to see how deep we can dig in.

First of all, this is a upload mode entering issue, we going to focus on, CH340 chip, buttons and related software.
Make use there is only the faulty board connect. And enter the upload mode.

• if there is com port, has log “Download Image over UART“. means the CH340(uart to use chip) functions and entered the upload mode successfully

• if there is has/no com port, with no log. means the log uart usb has some issues.

  • use correct baud rate to avoid any setting errors.

Try to connect an external UART to USB connector to see if there is log, AMB82-mini pinout

• if there is log, lets see if can enter the upload mode or not.
  • if no, that will be the button related issue.
• if there is no log, that is more complex.
  • it can be PCB internal line broken; wifi module not soldering well; or HW quality issue anywhere between IC to CH340.

before we go to button. let us see if the LED function well. Refer to hardware package for all circuit diagram.

from the circuit, we know that 23 (PF9) and 24(PE6) are blue and green. it can be tested, by connect VDD33 to Pin23 and 24, touch and go see if the LED is light up.

for button, SEN_PWR_EN linked to upload mode button, CHIP_EN linked to Reset button.

• reset button check, if there is no reset by button
  • connect chip_en to ground, touch and go, AMB82-mini pinout
    • the board should reset. if no, there will be more critical HW issue that suggested to replace this board.
• upload mode button check, if you can not enter the upload mode
  • find the SEN_PWR_EN,

    • there is no pin out for SEN_PWR_EN, but we can find a pin at the wifi module, refer to bellow. Right bottom corner (the circel) is the antenna connector. Top from right, the second pin is the SEN_PWR_EN.

      

    • test the SEN_PWR_EN and enter the upload mode

      • Connect VDD33 and SEN_PWR_EN, hold
      • Connect GND and CHIP_EN, touch and go
      • release VDD33 and SEN_PWR_EN

    • after the test you should able to enter the upload mode

      • if yes, most likely the EVB board has some HW issue
      • if no, the wifi module may have some HW issue

[M-ichae-l]

In short:
If the UART log is not visible, please use an external UART-to-USB adapter.
If the button can not enter upload mode, please try the SEN_PWR_EN method.

[Mel]

Thank you for your assistance. Last night I removed the Amb82 from the unpopulated PCB with pin headers I used for mounting and then found the board started to work, and would boot. I found using a microscope that a tiny solder fleck had shorted 2 pins near the boot button was the cause of the problem. All good now.
Mel