[hpsdr] [ATLAS] - proposed physical bus/pcb design 03March2006

Sun Mar 5 03:33:40 PST 2006

Phil

I think you meant this to go to the list, even if not, your points are well
taken. No question that the current available from the ATX is overkill. I
was also sitting here thinking "Where are the fuses?". 

OTOH: I am pretty much a 'plug and play' person, and for the cost of a 10
ohm 10 watt resistor, a switch, and a degree of caution, a standard computer
case with few modifications makes a pretty good 'end product'.

Using a small molex connector on the MB 'mandates' power supply
modification, even if only the cable.

As usual I feel strongly ALL ways! (smile), also really like that little
pico supply!

Thanks
Eric

-----Original Message-----
From: Phil Harman [mailto:pvharman at arach.net.au] 
Sent: Sunday, March 05, 2006 5:45 AM
To: Eric Ellison
Subject: Re: [hpsdr] [ATLAS] - proposed physical bus/pcb design 03March2006

Second take on the ATX connector.

The boards that we attach to the Atlas bus are in many cases going to be 
prototypes and development boards.  There is the inevitable chance that 
there will be circuit and operator errors.  With a full blown ATX power 
supply connected to the bus - that can provide may 10's of amps - such 
errors can be 'interesting' to say the least.  ATX power supplies are 
intended to power production designs that are not subject to tinkering. If 
we use a small Molex header then connecting up regulated and current limited

power supplies during the testing and development phases is very simple.

Since I don't see a high power PA being on of the six boards we don't need 
10's of amps anyway.  I'm not suggesting that we don't use ATX power 
supplies for a final and proven design - just not during the development 
phases.

I still support the case for a simple, small, Molex connector on the Altas 
bus.

Phil...VK6APH

----- Original Message ----- 
From: "Eric Ellison" <ecellison at comcast.net>
To: "'Eric Ellison'" <ecellison at comcast.net>; <pvharman at arach.net.au>; 
"'Philip Covington'" <p.covington at gmail.com>
Cc: "'High Performance Software Defined Radio Discussion List'" 
<hpsdr at hpsdr.org>
Sent: Sunday, March 05, 2006 6:12 PM
Subject: RE: [hpsdr] [ATLAS] - proposed physical bus/pcb design 03March2006

> Second take
>
> If a solution to the 20 - 24 pin is not quick and simple just stay with
> current design. It accommodates the slick little pico supply and is KISS.
> All the powers we need are on the 20 pin and Phil has allowed for the load
> resistor etc. 20 pin supplies will be around for a long time. Probably a 
> lot
> longer than the life cycle of the Atlas. Future rev of the Atlas when 24 
> pin
> supplies are far more prevalent than 20 pin is probably a better route.
>
> 24 pin to 20 pin adapter cables are readily available.
>
> My second 2 cents. And vote. Really nice design Phil! Build it and we will
> come!
>
> Thanks
> Eric
>
> -----Original Message-----
> From: hpsdr-bounces at hpsdr.org [mailto:hpsdr-bounces at hpsdr.org] On Behalf 
> Of
> Eric Ellison
> Sent: Sunday, March 05, 2006 4:17 AM
> To: pvharman at arach.net.au; 'Philip Covington'
> Cc: 'High Performance Software Defined Radio Discussion List'
> Subject: Re: [hpsdr] [ATLAS] - proposed physical bus/pcb design 
> 03March2006
>
> ***** High Performance Software Defined Radio Discussion List *****
>
> Phil
>
> Your design is so wonderfully flexible, in all ways, it seems a shame that
> we should not be able to accommodate the two current standard connectors 
> in
> some way, without having to hack the power supply. That would probably 
> give
> us 10 years, looking at the cycle for the 20 pin connector, change to 24.
>
> On board jumpers? Chris' suggestion of 2 connector provision?
>
> Thanks
> Eric
>
>
> -----Original Message-----
> From: hpsdr-bounces at hpsdr.org [mailto:hpsdr-bounces at hpsdr.org] On Behalf 
> Of
> pvharman at arach.net.au
> Sent: Saturday, March 04, 2006 10:44 PM
> To: Philip Covington
> Cc: High Performance Software Defined Radio Discussion List
> Subject: Re: [hpsdr] [ATLAS] - proposed physical bus/pcb design 
> 03March2006
>
> ***** High Performance Software Defined Radio Discussion List *****
>
> All,
>
> I appreciate that we have been through this design loop before but my vote
> is
> that we don't use either connector. A simple Molex socket with just the
> number
> of pins that we need will future-proof the project for the day when the 
> ATX
> connectors change again.  Making an adapter/chopping leads is easy.
>
> I appreciate that with the ATX connector we can remotely switch the PSU
> on/off
> but hooking into those two pins is easy.
>
> Just my 2c worth.
>
> 73's  Phil...VK6APH
>
>
>
>
>
> Quoting Philip Covington <p.covington at gmail.com>:
>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Hi Chris,
>>
>> Thanks for the link to the spec and the data sheet.
>>
>> Ken N9VV also sent me a link to the ATX 2.2 spec which describes the
>> 24 pin connector.
>>
>> I guess the big question now is whether we should stick with the 20
>> pin connector, go with the 24 pin connector, or put both on the board?
>>
>> I am in the process of adding the daisy chain bus requested by Lyle so
>> I can change or modify the connector arrangement also.  With 3 lines
>> on the XBUS and 3 lines on the YBUS used for the daisy chain, that
>> leaves us with an XBUS of 24 lines and a YBUS of 24 lines.   I did not
>> like the connector reference designator progression either so I have
>> fixed that.
>>
>> 73 de Phil N8VB
>>
>>
>> On 3/4/06, Christopher T. Day <CTDay at lbl.gov> wrote:
>> > Phil,
>> >
>> > My attached message gives the Mouser part number I found for the 24-pin
>> > version. I found it by looking for a match to what is specified for the
>> > plug in the ATX V2.2 Motherboard spec
>> > <http://www.formfactors.org/developer/specs/atx2_2.pdf>. Here is the
>> > data sheet for the header on the Mouser site:
>> > <http://www.molex.com/pdm_docs/sd/039281243_sd.pdf>. Is this enough
>> > info?
>> >
>> > Unfortunately, I think this header is not pin compatible with the 
>> > 20-pin
>> > version; the latch is in the wrong place and the pin across from #8 is
>> > NC instead of -5VDC as specified for the 20-pin connector in the ATX
>> > v2.1 spec
>> > <http://www.formfactors.org/developer/specs/atx2_1.pdf>
>> > I now have the picoPSU supply which is not modifiable to 24-pins, so 
>> > I'd
>> > be happy with the Atlas board as is.
>> >
>> >
>> >         Chris
>> >
>> >
>> > -----Original Message-----
>> > From: Philip Covington [mailto:p.covington at gmail.com]
>> > Sent: Saturday, March 04, 2006 3:22 PM
>> > To: High Performance Software Defined Radio Discussion List
>> > Subject: Re: [hpsdr] [ATLAS] - proposed physical bus/pcb design
>> > 03March2006
>> >
>> > ***** High Performance Software Defined Radio Discussion List *****
>> >
>> > On 3/4/06, Eric Ellison <ecellison at comcast.net> wrote:
>> > > Phil
>> > >
>> > > Fantastic. Many great ideas here. I really like the inclusion of all
>> > > voltages for experimenters! We had talked about using the new 24 pin
>> > ATX
>> > > connector which is apparently compatible with the current 20 pin
>> > connector.
>> > > This would allow for the future of the newer power supplies included
>> > with
>> > > future computer enclosures.
>> > >
>> > > Are you doing this in Kicad? If so can we get a holt of the project
>> > files?
>> > >
>> > > Thanks
>> > > Eric
>> >
>> > Hi Eric,
>> >
>> > I could not find a specification or reliable source of information
>> > concerning the pin out of the 24 pin connector mentioned.  Anyone?
>> >
>> > 73 de Phil C
>> > _______________________________________________
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>> >
>> >
>> >
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