New XMOS L2 board with USB ?

[Folknology]

Oh I'm fully aware of why they are good numbers for USB, especially the 12Mhz one! But you guys always use 13Mhz crystals on your USB implementations. Thats why It made me think that maybe you were also bit banging at 12Mhz or at least doing something different.

regards
Al

[waluigi]

....maybe you were also bit banging at 12Mhz....

Would that be possible in software?

[Folknology]

Bitbanging at 12Mhz isn't an issue, although I am not sure if the XS1 will be able to handle both edges, might need a buffer/inverter. Anyone at Xmos care to comment? or anyone else for that matter?

regards
Al

[dan]

Fellas, there's lots of interesting (official and unofficial) stuff forthcoming from the xmos hamsters around the points raised in this thread very soon.

As for bit banging at 12mhz, that's how our ipod dock dev kit works. Also check out:

https://github.com/xcore/sc_android_aap

[Folknology]

Thanks Dan

Is the bitbanged USB stuff open, unlike the ipod/apple stuff?

I couldn't see any code on the android proj but the XN file has some clues ;-)

regards
Al

[dan]

Al, its not open yet.

As ever, its a mainly question of time and effort to sanitize it and document it (its not the kind of thing easily used without docs).

Did you have a some use cases in mind?

[Folknology]

Well the obvious one is bitbanged usb virtual com port which has many uses. But also low bandwidth usb devices like keyboards/mice and game controllers etc...

Taking the idea even further:
If an open bitbanged USB basic library is available could we for instance port LUFA or similar onto it.

There are so many apps that just need low bandwidth (12Mhz) USB using up a minimum number of pins on an L1, it would be really useful to have.

I haven't even mentioned storage class and usb keys/dongles apps and bootloaders

regards
Al

[dan]

The bit banged USB is host only for the foreseeable future, and also not tested with hubs.

Does that work for LUFA?

[Folknology]

I think host is just one part of LUFA - http://www.fourwalledcubicle.com/LUFA.php

LUFA is also Atmel specific but there is a lot of good code there and APIs

I would like to see what resources are required by the Xmos soft usb -mem/ports/threads etc..

regards
Al

[Bianco]

I believe we should start with a 1.5Mbit low speed device first.
That can be easily implemented in XC. V-USB provides an excellent reference (where the USB protocol is bitbanged)