Uno Wifi Rev 4

[titantomorrow]

Hi,

I have found that the Lambda Shield 2 Example works on the new Uno Wifi Rev 4 board, returning the expected 20.95% result in free air.

However, I can only do this by first uploading the example without the shield attached. If I try to upload any program with the shield attached I get a board not found error. Does anyone have any idea why this would be? Could it be the power consumption of the shield? Can anyone suggest a workaround (other than unplugging)?

I do feel that people are very likely to want to use this shield with the new Uno Wifi Rev4 board.

warm regards,

Graham

[Christian_Bylund]

Hi,

I have found that the Lambda Shield 2 Example works on the new Uno Wifi Rev 4 board, returning the expected 20.95% result in free air.

However, I can only do this by first uploading the example without the shield attached. If I try to upload any program with the shield attached I get a board not found error. Does anyone have any idea why this would be? Could it be the power consumption of the shield? Can anyone suggest a workaround (other than unplugging)?

I do feel that people are very likely to want to use this shield with the new Uno Wifi Rev4 board.

warm regards,

Graham

Hi Graham,

Currently there is no work around but I can confirm that I see the same issue. Arduino UNO R4 Minima does not have the same problem using the same microcontroller. Arduino UNO R4 WiFi just started supporting Arduino BLE library with the latest update and it seems it is still struggling with some compatibility issues.

[titantomorrow]

Thanks for that, I'll get the minima :)

[titantomorrow]

It seems to have something to do with the reset pin. If I disconnect that, it works fine. Is the reset pin important on your shield?

[Christian_Bylund]

It seems to have something to do with the reset pin. If I disconnect that, it works fine. Is the reset pin important on your shield?

Thank you for the observation, it is only used to reset the CJ125 if the shield is reset but it should not have any importance in the function. I can see in the schematics that the RESET pin is connected to one of the GPIOs of the ESP32. So there is a chance this may be solved by a firmware update by Arduino in the future.

[viteka32]

Hi,

I have found the problem. Shield has a 1 nF capacitor on the reset line and Arduino has a 100k pull-up. This causes the pin to create a slow startup from logic 0 to logic 1.

Solution: Remove the capacitor or change the capacitor value, meaby 100 pF.

[DonP]

Solution: Remove the capacitor or change the capacitor value, meaby 100 pF.

@Christian_Bylund: do you second this? Or would this have negative implications if going back from the Uno R4 Wifi to the original Uno (non-R4) or the Uno R4 Minima?

Best regards,
Pascal

[tg1929]

Hi All, I realize this is an old post but this information might be of some use to others searching in the future.
I also faced the same issue with failing to load. I found I had to physically unplug the Lambda shield, load the updates to my program, then plug the shield back in.
I do have a problem that I cannot find a workaround for, the UNO Wifi R4 does not boot when powered up by the Lambda Shield. I have to push the reset button after I have supplied power. I could not test using serial debug output as the serial port powers the uno and fixes the problem but I added dome debug code to turn on the built in LED display during different stages of the setup code and found it does not enter the Setup at all. Once the reset button is pressed the shield works perfectly on the UNO WiFi R4, but its not practical to do this. I have moved back to a R3 which does not have this issue.