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Re: Attention all you USB junkies!

Posted: Wed Jul 12, 2017 11:44 am
by majenko
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.

Re: Attention all you USB junkies!

Posted: Sun Oct 08, 2017 6:39 pm
by Jacob Christ
I'm totally rolling this into my chipKIT class this year!

Thanks Manjenko!

Jacob

Re: Attention all you USB junkies!

Posted: Sun Oct 08, 2017 10:04 pm
by majenko
Yay! I've been masculated!

Re: Attention all you USB junkies!

Posted: Mon Oct 09, 2017 1:01 am
by EmbeddedMan
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