[avrdude-dev] Fixing LUFA AVRISPmkII

[Colin O'Flynn]

Hi All,

 

Long time since I last posted here, but I'm not dead or anything ;-) 

 

Anyway is there interest in changing the USB drain functionality? Basically
the problem is calling usbdev_drain() causes issues with 'clone' AVR-ISP
mkII's using Dean Camera's LUFA USB framework.

 

There is a basic patch posted at
http://www.avrfreaks.net/index.php?name=PNphpBB2
<http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&p=819522>
&file=viewtopic&p=819522 which disables this.

 

I'd suggest fixing by adding the usb-drain option as a command-line argument
perhaps? One could even detect the specific programmer & disable it just for
those (e.g. avr-isp mk2). According to commit comments the drain
functionality is required when things get out of sync with certain devices,
the commit comments mention the jtagice in particular. I have no idea how
useful it is, but I assume don't want to strip it out entirely.

 

I just ran into this myself & confirmed that disabling the drain function
fixed the issue. Considering a lot of people are probably using this
open-source MK2, it might be a nice thing to fix.

 

If it sounds reasonable I'll make up a patch, although it might be a week or
two away as will be travelling for a conference shortly.

 

Warm Regards,

 

  -Colin O'Flynn