[hpsdr] Hermes

[Phil Harman]

Hi Rob,

I will look at that since it would solve the problem of FPGA pins. One
other advantage of the Ethernet solution is that a 125MHz clock is all we
need for the entire board.  We would need an additional 24MHz clock for
the USB.

Jumper selecting some 20+ pins could also be a problem particularly since
the PHY data is at 250MHz.

I've also had a chance to use the Ethernet connection to HPSDR for a few
days.  It is so much nicer than USB. No driver issues, at Gig-E I can
unplug all the cables (with the PC and OyzII still connected) and plug
then back in and it all starts automatically.

73's Phil...



> Hi Phil,
>
> Have you considered possibly having both circuits on the board, so that
> one or the other could be selected with a set of physical jumpers to
> connect the pins to the USB part or the ethernet part of the circuit?
>
> 73,
>
> Rob
>
> On 08/05/2010 08:20 PM, Phil Harman wrote:
>> Hi Rob,
>>
>> I don't think we will have enough FPGA pins to have both options.
>>
>> 73's Phil...
>>
>>
>>
>>> ***** High Performance Software Defined Radio Discussion List *****
>>>
>>> Hi Phil,
>>>
>>> I vote for ethernet as well, but I'm wondering how much it would add to
>>> the complexity and cost to leave the USB interface on there as well.
>>>
>>> 73,
>>>
>>> Rob, KL7NA
>>>
>>> On 08/04/2010 07:18 PM, David McQuate wrote:
>>>
>>>> ***** High Performance Software Defined Radio Discussion List *****
>>>>
>>>> I vote for Ethernet.  (I believe I heard you had a way of loading the
>>>> FPGA over Ethernet. True?)
>>>> 73,
>>>> Dave
>>>>
>>>> Phil Harman wrote:
>>>>
>>>>> ***** High Performance Software Defined Radio Discussion List *****
>>>>>
>>>>> All,
>>>>>
>>>>> Having completed the Beta testing of Hermes we are now preparing to
>>>>> make
>>>>> the necessary changes to bring the board into a production ready
>>>>> state.
>>>>>
>>>>> There are quite a few changes which are mainly due to the fact we
>>>>> want to
>>>>> ensure the product lives up to the 'High Performance' name tag.
>>>>>
>>>>> One of the changes is to replace one of the high current linear
>>>>> regulators
>>>>> with a SMPSU. We are fortunate to have Kjell, LA2NI,  on our design
>>>>> team.
>>>>> Kjell has designed a high frequency SMPSU that works well when
>>>>> incorporated on the Hermes PCB and does not introduce significant
>>>>> spurs. This substantially reduces the current drain and also the heat
>>>>> dissipation.
>>>>>
>>>>> The other potential change is this.  I have this week build a
>>>>> prototype
>>>>> OzyII Gigabit Ethernet board. It works very well and I'm impressed
>>>>> with
>>>>> how rugged Ethernet appears to be in comparison to USB and Firewire.
>>>>>
>>>>> We therefore have the opportunity to replace the USB interface on
>>>>> Hermes
>>>>> with Ethernet.  There are a number of advantages in doing this:
>>>>>
>>>>> - we overcome the USB driver issues when using different operating
>>>>> systems
>>>>> - we can 'network attach' Hermes
>>>>> - we will have a very high speed interface to the board for future
>>>>> features
>>>>> - we can use a much longer Ethernet cable than USB allows
>>>>>
>>>>> the disadvantages
>>>>>
>>>>> - it may need more that one spin of the PCB which will delay the
>>>>> delivery
>>>>> - we will use approximately 10% of the FPGA to implement the Ethernet
>>>>> interface.
>>>>>
>>>>> I'm not too concerned about using more of the FPGA since the device
>>>>> we are
>>>>> using is 70% larger than that used on Mercury.
>>>>>
>>>>> So "to USB or not to USB - that is the question"?
>>>>>
>>>>> 73's Phil...VK6APH
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>>
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>>> --
>>> Rob Frohne, Ph.D., P.E.
>>> E.F. Cross School of Engineering
>>> Walla Walla University
>>> 100 SW 4th Street
>>> College Place, WA 99324
>>> (509) 527-2075			 http://people.wallawalla.edu/~rob.frohne
>>>
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>>>
>>
>>
>
> --
> Rob Frohne, Ph.D., P.E.
> E.F. Cross School of Engineering
> Walla Walla University
> 100 SW 4th Street
> College Place, WA 99324
> (509) 527-2075			 http://people.wallawalla.edu/~rob.frohne
>
>



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