Missing COM Port

Hello,

I think I messed up gravely...

I'm programming using Arduino IDE onto two Canbed RP2040's (which uses the Raspberry Pi 2040). Documentation can be found here: CANBED RP2040 - Longan Docs

I was attempting to make the two devices communicate over I2C. After uploading the following sketch to Device A,

#include <Wire.h>

#define Rp2040_I2C_ADDRESS  0x55
#define Rp2040_I2C_SDA  6
#define Rp2040_I2C_SCL  7

void setup() {
  // put your setup code here, to run once:
  Wire.setSDA(Rp2040_I2C_SDA);
  Wire.setSCL(Rp2040_I2C_SCL);
  Wire.begin(Rp2040_I2C_ADDRESS);  // joins i2c bus at address 0x55
  Wire.onRequest(eventReq);
}

void eventReq()
{
  Wire.write("Hello "); // 6 char -> 6 bytes (any data over 6 bytes disregarded by master)
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(200);
}

Device A no longer shows up on the Com Port. Everytime I disconnect/reconnect the device, I get a Window error that the last "USB Device Malfunctioned...". Device B's COM Port shows up perfectly fine. I've tried swapping the USB Cable, USB Port, restarting my PC and no dice.

Please help if possible

Hi @scarh201. Are you still able to upload sketches to your "board A"?

If so, does the problem of the board not producing a port still occur after you upload the simple sketch that is produced by selecting File > New Sketch from the Arduino IDE menus?

No, I cannot upload any sketch to Board A at all. When I access Device Manager, the connected Port is under "Unknown USB Device (Device Descriptor Request Failed)"

I think I found a workaround... using the Bootloader mode, I just dropped a .uf2 file into the Mass Storage Device. Fixed the error. Thanks for your help

I'm glad you were able to discover the technique to restore the board to the state where you can upload to it once more. Thanks for taking the time to share an update with your findings! I'm sure the other users who run into a similar problem and find this thread while searching for a solution will be grateful.

Regards,
Per

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