Kevin Vance - More VK204-25-USB fun: the device actually fails the USBCV 1.3.1…

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08:10 pm

Friday, February 29th, 2008
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More VK204-25-USB fun: the device actually fails the USBCV 1.3.1 compliance test because it reports a zero-length read buffer. Oops! I'm hoping to come up with some kind of software workaround for linux, since windows obviously manages to do it.

Update: Success! Now when the device is detected, I overwrite the the kernel's copy of the wMaxPacketSize with its "real" value (i.e. NOT the one provided by USB). The serial port is now usable.

However, I'm not out of the woods yet. LCDd can't *quite* communicate with it properly. But I have tested a bunch of the commands by writing them directly to the serial port, and it all seems to work. So, now that I've fixed the USB driver, it's time to fix the serial protocol driver :)
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From: c99koder
2008-03-01 03:41 am (UTC)
Make sure you're using the MtxOrb driver and that you've specified that it's a VFD and not an LCD. That config file tripped me up the first time I set mine up.. very poor layout!
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[User Picture]From: kvance
2008-03-01 07:17 am (UTC)
I tried all of the options. vkd looks like the correct one, but they all do about the same thing: 98% of the text is there, with random custom characters in some spaces. I'm pretty sure more hacking is in order.
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[User Picture]From: rspeed
2008-03-01 11:32 pm (UTC)
Ugh. And they're changing money for it?
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[User Picture]From: kvance
2008-03-02 01:25 am (UTC)
As a linux user, I just assume that random peripherals aren't going to work :)
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