Well, I’m really starting to run out of things to implement. Seriously; I’ve now made demos for the majority of the standard USB classes. Still, I’m revisiting an idea given to me by several people - a CDC class bootloader.
MyUSB already has a DFU class bootloader, of course, but that is incompatible with most of the software for AVR programming. By writing a bootloader based on the CDC class, it could enumerate as a virtual serial port and support the common AVR109 bootloader protocol. This would render it compatible with such commonly used software as AVR-OSP and AVRDude.
My only concern is size constraints; the bare CDC code with no functional use of the data sent and received leaves only about 1.5KB of space for the bootloader code. However, if the assembly nuts can get it done in half a kilobyte, I’ll be damned before I let this defeat me. Stay tuned.
April 22nd, 2008 at 6:30 am
While I am not sold completely on the DFU-Bootloader it does work.
It seems that you should ask Joerg what could be rolled into easily avrdude and focus on a light weight usb device with avrdude support, rather than trying to wedge the driverless cdc up into a small space.
Avrdude has support for several usb devices that are well handled cross platform via libusb.