Re: [libusb] less data length in async bulk transfer with 2 cameras

[zheng r. <zhe...@gm...>]

Thanks a lot for your help, Tim. Finally I got the isoc transfer mode
worked by reducing the pixel clock to 22MHz without external FIFO.
The FIFO chip you mentioned is indeed not available, and new FIFO chip is
expensive. It seems reducing the pixel clock is good choice for my current
application.

Best regards,
Zheng




Tim Roberts <ti...@pr...> 于2018年11月3日周六 上午2:01写道：

> Tim Roberts wrote:
> > On Nov 1, 2018, at 9:06 PM, zheng rong <zhe...@gm...
> > <mailto:zhe...@gm...>> wrote:
> >>
> >>     > How did you fix the problem finally?
> >>
> >>     Third -- the real solution -- was to spin the camera board to add
> >>     a 32k
> >>     external FIFO chip.
> >>
> >>
> >> Would you please provide the part name of the external FIFO chip?
> >
> > I'll see if I can find that out.  It was 10 years ago...
>
> Amazingly, I found the schematic.  It was a Cypress CY7C4251, which is
> only an 8k FIFO.  I though they added 32k, but I remembered
> incorrectly.  I assume they're no longer available; chips don't have a
> long life these days.
>
> It is an 8Kx9 unit; we passed the 8 data bits plus PKTEND.
>
> --
> Tim Roberts, ti...@pr...
> Providenza & Boekelheide, Inc.
>
>
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