On 23/12/2010 00:03, Philip Pemberton wrote:
> Quick question -- what's the fastest anyone's managed to transfer data
> from a PIC18F85J50 to or from a PC, using USB?
>
> After a heck of a lot of protocol tweaks and the addition of
> double-buffering (which netted me another 20 kbytes/sec), I'm up to a
> shade under 220 kbytes/sec. Is this about right for a chip with the PLL
> on and a core clock of 48MHz?
>
> The data is being sourced from the Parallel Master Port -- data either
> goes from USB to PMP, or the other way.
>
> The source code is online at http://hg.discferret.com/firmware/ for the
> curious. This includes a patch to the Microchip USB Stack which adds a
> 'special' string descriptor that reads the device serial number from the
> end of the bootloader block of the Flash.
>
> Thanks,

I think the max speed USB 1.1 will do in reality with wind behind it,=20
down hill is about 780 k Bytes /s

Assuming 24MHz USB clock =3D 12Mbps data rate
--=20
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