On Thu, Feb 15, 2001 at 09:30:53AM -0500, Steven Grunza wrote:
   > It would seem, in theory, that a "winmodem" type of device could provide
   > better performance since it's data path into the system is across a
   > parallel bus and not through the serial port.  Also, if the "winmodem" were
   > to DMA it's data into a region of memory and then interrupt the CPU, it
   > would seem that the system processor could get an interrupt per packet
   > instead of an interrupt per character...Just a thought....

   Err.. AFAIK, the winmodems use the system CPU for a DSP, so they require
   relatively much processing power.  I don't know if I'm correct, but I
   would guess that the winmodems have only A/D and D/A converters with FIFOs
   and the system CPU has to analyze the sampled waveforms and produce output
   waveforms (this is done by a dedicated DSP chip in "real" modems).

   (But I can still understand that people would like to use all the hardware
   they've got, so a NetBSD driver would be nice.)

     -jm


I think that the above configuration is called 'HSP', where the host does
the waveform generation.  I believe that there are "winmodem" devices that
have DSP hardware on board, but without a UART and the rest.


Brad Spencer - brad@anduin.eldar.org
http://anduin.eldar.org  - & -  http://mellon.ipv6.eldar.org [IPv6 only]
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