[uCsimm] SPI - REALTIME - ETHERNET

From: Peter E. Thomas (peter@beast.ods.org)
Date: Thu May 04 2000 - 03:08:50 EDT


Hello All-

I have a question about how the ucsimm will handle a realtime task. My
setup is basically this:

 1. PC running Windows NT, with an ethernet card
 2. ucsimm connected to PC via ethernet
 3. a "decoder" card connected to the SPI port on ucsimm.

What I want to do is send a packet to the ucsimm containing coded speech.
The data from this packet will be taken out and sent out the SPI port.

Now, it needs to be sent out the SPI port in a special fashion. Every 125
micro seconds, I need to send 2 bytes. I figure that when I send the TCP
packet to the ucsimm, I will give it about 1000 bytes to work with.

The same thing needs to work in reverse. The decoder card will be sending
2 bytes 8000 times a second through the SPI to the ucsimm. I need the
ucsimm to buffer some ammount (I don't know how much...) and then send the
packet to the Windows NT box.

It seems this is going to be VERY tight, maybe not possible. How long
should I bufffer data in the ucsimm when it is reciveing from the decoder?
How long does it take to send a 1000 bytes packet? a 100 byte packet?

Anyone ever tried anything liek this? Would I be better off using a
codefire board?

        Thanks for your time!
        Peter

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