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Re: [Discuss-gnuradio] Alternative interface from PC to a USRP.
From: |
Lamar Owen |
Subject: |
Re: [Discuss-gnuradio] Alternative interface from PC to a USRP. |
Date: |
Sat, 9 Jul 2005 14:36:27 -0400 |
User-agent: |
KMail/1.8.1 |
On Saturday 09 July 2005 12:58, David Carr wrote:
> How many pins does Ultra320 require, is it 32x2 (differential) = 64?
The connector is a 68 pin connector, and the bus is 16 bits. By using two 68
pin connectors you can get 32 bits wide; very few host adapters are available
to do that, but that would get you 640MB/s (160megawords per second).
> Also what are the max cabling lengths at this speed?
For LVD Ultra 320 SCSI, the max bus length (terminator to terminator) cannot
exceed 12 meters (39 feet).
For single-ended (non-twisted pair cable) the max length varies according to
speed. For 40MB/s (20 megatransfers per second) SE can go 1.5 meters; for
20MB/s 3 meters, and for 10 MB/s (5 MT/s) 6 meters.
> What is the clock rate on those pins?
160MHz, low voltage differential on twisted pair.
> You mention the ability to send data between hosts without CPU
> intervention. Does that mean its possible to send data from the USRP to
> multiple hosts connected on the same SCSI bus?
Yes.
> By the way I think that gigabit is 1Gbps full-duplex ie: 2Gbps.
Sure, if you are doing both transmit and receive. But you would be limited to
1Gb/s for receive-only.
--
Lamar Owen
Director of Information Technology
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC 28772
(828)862-5554
www.pari.edu
Re: [Discuss-gnuradio] Alternative interface from PC to a USRP., Matt Ettus, 2005/07/09
Re: [Discuss-gnuradio] Alternative interface from PC to a USRP., Eric Blossom, 2005/07/09