Disconnect USB (Native) in sofwtare

Official Hardware Classic Zero
1

Hi,

I've an issue when I try to jump between to Arduino application stored simultaneously in flash.
If the USB cable is plugged in the native port, the second application doesn't start. I think it is due to some USB registers not being reset, but I can't figure out which one(s).

here is the code to jump between application :

extern "C" {
#define APP_START_ADDRESS 0x10000

  void jumpApplication() {
    /* Pointer to the Application Section */
    void (*application_code_entry)(void);
    /* Rebase the Stack Pointer */
    __set_MSP(*(uint32_t *) APP_START_ADDRESS);
    /* Rebase the vector table base address */
    SCB->VTOR = ((uint32_t) APP_START_ADDRESS & SCB_VTOR_TBLOFF_Msk);
    /* Load the Reset Handler address of the application */
    application_code_entry = (void (*)(void))(unsigned *)(*(unsigned *)(APP_START_ADDRESS + 4));
    /* Jump to user Reset Handler in the application */
    application_code_entry();
  }
}

it is called like this :

    ...
    ...
    SPI.end();
    dma.end();

    //some kind of USB.end()...
    //p763 of datasheet
    USB->DEVICE.CTRLA.bit.ENABLE=0;
    USB->DEVICE.CTRLB.bit.DETACH = 1;
    USB->DEVICE.INTFLAG.bit.SUSPEND = 1;
   
    digitalWrite(13, LOW);
    jumpApplication();

Has anyone an idea how to solve this?

2

I tried to make USB pins high impedance with pinMode(28, INPUT_PULLUP); but it doesn't solve my issue...

3

This code does disconnect the USB Port :

USB->DEVICE.CTRLA.bit.SWRST = 1;

while (USB->DEVICE.CTRLA.bit.SWRST == 1);

But when the second application start, the code still hangs... I'm investigating the USB core lib.