Attention all you USB junkies!

Announcements for new builds and MPIDE enhancements
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majenko
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Re: Attention all you USB junkies!

Post by majenko » Wed Jul 12, 2017 11:44 am

ok, high water mark implemented (I think). It's much slower now - a more realistic speed. Not fast, but then I've not written it to be fast (yet) - only to work which, given the lack of any documentation, is a small miracle ;)

Peak speed seems to be with 8 byte packets, which cause no stalling to occur. This yields about 600Kbytes per second. Less than that and the packets get too small to be efficient and the overheads are too great - it slows down. Larger than that and stalling starts to occur as the code can't read the buffer fast enough, and the speed drops.

So at the moment with inefficient code (copying data manually between FIFO and buffer, then between buffer and circular buffer), and reading with readBytes() it's on a par with a Teensy using read(). 6x faster than a Due, though, and a little faster than an MX using read().

Room for improvement, yes, but still not bad considering.
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Jacob Christ
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Re: Attention all you USB junkies!

Post by Jacob Christ » Sun Oct 08, 2017 6:39 pm

I'm totally rolling this into my chipKIT class this year!

Thanks Manjenko!

Jacob
PONTECH Quick240 an industrial form factor platform for chipKIT and Arduino users.

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majenko
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Re: Attention all you USB junkies!

Post by majenko » Sun Oct 08, 2017 10:04 pm

Yay! I've been masculated!
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EmbeddedMan
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Re: Attention all you USB junkies!

Post by EmbeddedMan » Mon Oct 09, 2017 1:01 am

I've been using this new USB stack pretty much non-stop for a couple months now, and have zero problems with it as a CDC serial replacement.

I think one of our next steps for the chipKIT project is to roll this new stack into a v2.0 core release before the end of the year.

*Brian

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