General • Re: Minimal C code to detect RP2040 plugged to a USB host?

Code:

    // Minimal enable of the USB PHY, just so we can tell if something    // is plugged in to the daughterboard socket.    // We can tell this as a USB device will pull up the DP pin,    // but we need to enable the pull-downs on DP/DM to avoid stray    // pickup.    usb_hw->phy_direct_override =        USB_USBPHY_DIRECT_OVERRIDE_DM_PULLDN_EN_OVERRIDE_EN_BITS        | USB_USBPHY_DIRECT_OVERRIDE_DP_PULLDN_EN_OVERRIDE_EN_BITS;    usb_hw->phy_direct = USB_USBPHY_DIRECT_DM_PULLDN_EN_BITS        | USB_USBPHY_DIRECT_DP_PULLDN_EN_BITS;             for (unsigned u = 0; u < 100; u++)    {        if ((usb_hw->phy_direct            & (USB_USBPHY_DIRECT_RX_DP_BITS | USB_USBPHY_DIRECT_RX_DM_BITS)            )            ==  USB_USBPHY_DIRECT_RX_DP_BITS)        {            printf("Daughterboard detected\n");            OUR_UID = (OUR_UID & 0x00ffffff) | (UID_UBHU_ENT << 24);            break;        }        busy_wait_ms(1);    // Allow up to 100ms before giving up.    }