Code Snippets

Reset and stay in the Adafruit bootloader

    use atsamd_hal::pac::SCB;

    /// RAM size (32 kB for ATSAMD21E18A)
    const HMCRAMC0_SIZE: u32 = 0x00008000;
    /// RAM base address
    const HMCRAMC0_ADDR: u32 = 0x20000000;

    /// Writing this value into `BOOTLOADER_DBL_TAP_PTR` and resetting will
    /// cause the bootloader to 'stick'
    const BOOTLOADER_DBL_TAP_MAGIC: u32 = 0xF01669EF;
    /// Writing this value into `BOOTLOADER_DBL_TAP_PTR` and resetting will
    /// cause the bootloader pass right through to the app
    const BOOTLOADER_DBL_TAP_MAGIC_QUICK_BOOT: u32 = 0xF02669EF;
    /// Bootloader magic values need to be written here
    const BOOTLOADER_DBL_TAP_PTR: *mut u32 = (HMCRAMC0_ADDR + HMCRAMC0_SIZE - 4) as *mut _;

    /// Reset into the bootloader, and stay there in order to flash a new
    /// firmware image.
    #[inline]
    pub fn reset() -> ! {
        unsafe {
            core::ptr::write_volatile(BOOTLOADER_DBL_TAP_PTR, BOOTLOADER_DBL_TAP_MAGIC);
        }
        SCB::sys_reset();
    }