USB FS Maximum Throughput

[chibby]

Only USB-device is supported.

Thanks for the reply. Is there a problem with implementing USB 2.0 HS ? Is that too fast to do in RTOS context?

[Giovanni]

It is already implemented.

Giovanni

[chibby]

OK. I've googled previous threads on this, as you suggested, and I don't see anyone getting much beyond 1MB/s.

Is there a demo I can try to demonstrate USB 2.0 HS transfer rates?

Thanks.

[Giovanni]

It is new code, I have not measured performance yet but I am sure it will not reach USB 2 limits, there are other limitations, queues mainly, data copying is done in SW.

Giovanni

[rew]

IIRC, these boards provide USB 2.0 "Hi Speed" but only 1.1 "Full speed" in OTG mode. I'll have to check the spec to be sure.

The chips ('405 and the likes) have TWO USB controllers. One of them is "FS", 12 Mbit per second, and you seem to be able to achieve 100% of that theoretical maximum with your serial experiment. Great.

The other one is FS/HS..... This means that you can pair it with an external "HS link level driver", to achieve "high speed". Or you can use it at "FS", 12Mbit if you want.

I've tried getting the stuff to work with the companion chip (I used an "USB3300"), and failed.This is definitively my problem as others have gotten it to work.

[chibby]

Well there's a 40x difference between FS and HS , so even if if does not get close to theoretical max, there may still be an order of magnitude improvement on circa 1MB/s.

What version do I need to test this? v3.0.2 , or do I need trunk?

I see some recent changes giving more direct access, which seems relevant. Are there any pointers you can give me about setting up a speed test that is likely get the best results. That could save me wasting time if you can point the way.

Thanks.

[Giovanni]

Trunk, there is a demo on the F7.

Giovanni

[chibby]

Many thanks. I have an F4, I'll try to find time to adapt that test demo and post what I get. I grabbed trunk last night in anticipation.

[rew]

But... Do you have the HARDWARE for "high speed"? You're at 100% efficiency for "full speed".

[chibby]

Perhaps you need to READ the rest of the thread before trying to contribute.