USB bootloader with AT90USB1286

[behranghm]

I am using a bootloade sample code which turns at90USB1286 into a DFU class bootloader which works perfectly well with Atmel’s FLIP application under AVRstudio. Now my problem is that it only works just once and the apparent reason is that as I program the device with a USB flash application via the DFU bootloader, the DFU driver is uninstalled from the PC and is replaced by the application driver. I think just like the UART bootloader which should be supported by the main application, I should be using a USB application with dual configuration, one for the application itself and another one for the DFU bootlaoder. Now you guys, any hints? About such an application ? How about the drivers for such an application?

 

[FvM]

I understand, that the availability of the DFU bootloader doesn't depend on the driver, but on either starting the bootloader or the application. The DFU manual discusses several options how this may be performed, e. g. a hardware button or a JMP from the application. But I didn' yet evaluate these options.

 

[behranghm]

Now that’s great, by any chance does anyone know of any application software which could successfully jump to flash bootloader section if a certain data is sent via the USB? Could it be as simple as this? I loaded the DFU into the device and I inserted the following code in the application software:
if(“certain condition”)
{ asm
(
"jmp 0xf000 \n\t" //start address of the bootloader.
"cli "
);
But it’s not working, any clue?

Added after 2 hours 29 minutes:

I just managed to lunch the bootloader by sequentially pushing the RESET and HWB buttons according to Atmel’s manual. It works perfectly well with FLIP. But I am looking for a way to this entirely in software with no hardware manipulation. Any solutions? Hints?