Subject: Re: Hope for winmodem support?
To: None <firstname.lastname@example.org>
From: Brad Spencer <email@example.com>
Date: 02/15/2001 09:53:55
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.)
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 - firstname.lastname@example.org
http://anduin.eldar.org - & - http://mellon.ipv6.eldar.org [IPv6 only]
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