On Jun 18, 2010, at 2:08 PM, Richard Ferch wrote:
> However, according to the
> documentation for JE3HHT's implementation of EXTFSK (comfsk105.zip), it
> uses the multimedia timer to control timing.
The Windows multimedia timer is specified with a granularity of 1 ms
(http://msdn.microsoft.com/en-us/library/dd757633(v=VS.85).aspx).
Isochronous transfers is something different. See for example here:
http://www.silabs.com/Support%20Documents/TechnicalDocs/AN295.pdf
Notice that USB isochronous transfers are only available for the USB Audio
Class, not even for mass storage class (which don't care if you inject pauses
now and then), for example.
You can find information about other USB class here
http://www.usb.org/developers/devclass_docs#approved
BTW, notice that there is no "serial port" USB Class. Manufactures that
produce USB serial port adapters need to supply the drivers, which might or
might not come preinstalled in an operating system.
73
Chen, W7AY
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