DFU: Introduce board/app-specific override for booting in DFU mode
Using the USBDFU_OverrideEnterDFU() function, a board/application can
define extra conditions when the system should boot in DFU mode, even if
it was not explicitly switched to DFU mode from the application.
The app/dfu/main.c uses this mechanism to boot into DFU mode if the
stack + reset vector addresses are not plausible (i.e. some random junk
appears to be flashed in the application partition) or if the user
places a jumper accross the RxD+TxD lines of the debug UART. The idea
is that the system can be recovered by placing this jumper and then
re-installing the application from DFU.
diff --git a/firmware/atmel_softpack_libraries/usb/device/dfu/dfu.h b/firmware/atmel_softpack_libraries/usb/device/dfu/dfu.h
index 4af3e3b..87ac060 100644
--- a/firmware/atmel_softpack_libraries/usb/device/dfu/dfu.h
+++ b/firmware/atmel_softpack_libraries/usb/device/dfu/dfu.h
@@ -110,6 +110,7 @@
uint8_t *data, unsigned int len);
extern int USBDFU_handle_upload(uint8_t altif, unsigned int offset,
uint8_t *data, unsigned int req_len);
+extern int USBDFU_OverrideEnterDFU(void);
/* function to be called at end of EP0 handler during runtime */
void USBDFU_Runtime_RequestHandler(const USBGenericRequest *request);