Re: Improving Windows support for AVRDUDE

[Xiaofan Chen]

On Wed, Dec 1, 2021 at 3:40 AM Joerg Wunsch <j@uriah.heep.sax.de> wrote:
> The latter is what ARM went for, with their CMSIS-DAP spec. I think
> it's a big crock, but the grok "every device looks like a human
> interface" is quite present in many places, mainly due to Windows not
> providing a generic USB driver for every device straight from the
> beginning of their USB support (WinUSB came much later). As they
> (obviously) did have to provide out-of-the-box HID support, people
> went that way. ("Please install a device driver for your keyboard.
> Press <Enter> to continue." :-)

CMSIS-DAP has two version, one for HID and the other
with WinUSB.

For HID devices, we recommend HIDAP and not libusb.
https://github.com/libusb/libusb/wiki/FAQ#Does_libusb_support_USB_HID_devices

> Having said this, as long as it doesn't break libusb support (which is
> the common baseline for all Unix-like systems), and doesn't add a
> truckload of more #ifdefs, it's certainly fine to have that. If it
> works well, I even think libusb support is no longer needed for
> Windows anymore. It only went there in order to support Windows at
> all.

As mentioned in the other reply, it is good to move away
from libusb-0.1 API to libusb-1.0 API.

> > The easiest way to get Windows to load the WinUSB driver
> > automatically, is to add a WinUSB compatibility descriptor to the device
> > firmware.
>
> That's again where I don't really understand Windows. Why is it
> necessary to have *any* specific hack at all? Why couldn't they just
> offer WinUSB for *every* device, at least for every device that hasn't
> any more specific driver?
>
> But OK, we won't change Microsoft here. It's just cumbersome to deal
> with.

Yes it is unfortunate that Microsoft does not ship with a generic
USB driver...

But then more JTAG debuggers or programmers are moving to
WinUSB driver or HID, and with things like Zadig, life is as difficult
as before under Windows.

> I'd be more than happy to have a Windows guy in the boat, hopefully
> including someone who can roll native Windows binary releases as well.
> So far, I've always been rolling them using a MinGW32
> cross-compilation on my FreeBSD development system, but that isn't
> something running very smoothely anyway. So well, if you want to
> actively support AVRDUDE development on the Windows front, be welcome!
>

I will recommend Windows developers to use MSYS2 which
has good infrastructure to support building avrdude from source.

$ pacman -Ss avrdude
mingw32/mingw-w64-i686-avrdude 6.3-2
    Software for programming Atmel AVR Microcontrollers (mingw-w64)
mingw64/mingw-w64-x86_64-avrdude 6.3-2
    Software for programming Atmel AVR Microcontrollers (mingw-w64)

I provide libftdi binaries for Windows and it does not take much time
for me to do that regularly with the help of MSYS2.
https://github.com/mcuee/libftdi/releases
https://sourceforge.net/projects/picusb/files/

-- 
Xiaofan