Question about USB on the minimig

[downix]

Alright, let's crunch the numbers:

USB is a CPU-driven, not DMA driven, system.  That means for every batch call, the CPU must be utilized.

For a single mouse, you will, at peak, utilize 12Mbps, roughly 1.5MB/sec.  Now, the Amigas RAM speed is only 7MB/sec.  So, for a single, solitairy mouse, you'd be tying up 40% of RAM access.... just imagine adding a keyboard.

[downix]

Floid wrote:

downix wrote:

For a single mouse, you will, at peak, utilize 12Mbps, roughly 1.5MB/sec.  Now, the Amigas RAM speed is only 7MB/sec.  So, for a single, solitairy mouse, you'd be tying up 40% of RAM access.... just imagine adding a keyboard.

...but non-insane_laser_2-trillion_DPI mice are low-speed devices operating at 1.5m*bits*/s, yes?

Still bothersome but somewhat less so.

Nope, not bits, Bytes.  Even if you're only sending one pip of information, requiring only a byte, it sends a full 32-bit word down the pipe.  Very inefficient.

[downix]

techie wrote:

downix wrote:
Alright, let's crunch the numbers:

USB is a CPU-driven, not DMA driven, system.  That means for every batch call, the CPU must be utilized.

For a single mouse, you will, at peak, utilize 12Mbps, roughly 1.5MB/sec.  Now, the Amigas RAM speed is only 7MB/sec.  So, for a single, solitairy mouse, you'd be tying up 40% of RAM access.... just imagine adding a keyboard.

Sorry I'm probably just being Thick here but if this is the case then I have to ask; How does the Anaiis USB stack work then???  :-?
Because it claims to be working on a pretty much stock Amiga 2000 with ZorroII Highway USB and 68000 processor (7.14 Mhz).
(http://aminet.net/package/driver/other/anaiis)

 wouldn't know, as the source to both products is quite closed it appears.  Could be that there's an embedded controller.  Could be that the guy went "fsck it" and ate the performance loss.  Don't forget, you too can render Toy Story on your Amiga 1000.... it just would take centuries.

But it does not make things a practical solution.