>>> You'd trust a USB serial chip at 500k+ ? :)
>> I assume you wouldn't? Can you share why? We (and many others I
>> know) are using a USB COMi: http:// www.byterunner.com/byterunner/
>> product=name:USB-COMi (It's either the USB-COMi-SI-M or the USB-
>> COMi-M -- I don't have the device in front of me right now), to do
>> LIDAR signal processing at 500Kbps (RS422). We have not
>> experienced any problems. I'm very curious to hear why you
>> wouldn't trust such a device. Thanks, Tom.
>
> I've just had varying degrees of luck with consumer USB to Serial
> chips. The FT232 is mass produced, and used all over the place,
> I'd compare this in the audio world to products made by Behringer.
> Their stuff works most of the time, but it's not the greatest.
> Another worry I have about running one at 500k+ is that USB 1.1 has
> a throughput of 1.2Mbps, take away some for overhead and you're
> looking at around 1Mbps usable. A few errors or any weirdness, or
> something else on the bus and poof, there goes your 500k throughput.
>
I'm not familiar w/ the audio products you mentioned above but I
appreciate that being burnt once or twice by "something" causes you
to carry around baggage ... I certainly have my own about various
pieces of technology.
WRT "errors and weirdness" at the high speeds I know what you are
saying but for us, using RS422 at the electrical level and a robust
CRC algorithm to verify the incoming digitized data stream in the
application code has been working out very well with very few
hiccups ... when a hiccup is encountered our userland driver (which
is specific to the LIDAR signal we are processing) also recovers very
quickly (e.g. if the CRC on a packetized portion of the data stream
does not check out, we can resync very fast and just keep on
truckin...).
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