Searching \ for '[AVR] Freeduino Board (was kicad autorouting)' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=freeduino+board
Search entire site for: 'Freeduino Board (was kicad autorouting)'.

Exact match. Not showing close matches.
PICList Thread
'[AVR] Freeduino Board (was kicad autorouting)'
2007\10\05@182558 by William \Chops\ Westfield

face picon face

--Apple-Mail-8-715055577
Content-Transfer-Encoding: 7bit
Content-Type: text/plain;
       charset=US-ASCII;
       format=flowed


On Oct 5, 2007, at 2:14 PM, David VanHorn wrote
>
> Just don't tell me you used 22pF crystal caps on a 22pF crystal..  :)

Who can tell?  Someone else did schematic entry, and it's one of
those typical hobbyist projects that says "16 MHz crystal" with
no further specifications :-)  It does have 22pf caps...

>  If you route a specific track, from the
> ground side of both caps, to the nearest ground pin on the AVR, and
> only then, join the plane, you'll find that it makes the board
> significantly quieter.

Hmm.  I was happy to get a "ground ring" around the crystal and caps,
and thought that would help.  You're saying the ground ring and the
cap grounds should connect to the AVR ground pin separately, even
though they're really close?  There's ground plane on the bottom, too.


--Apple-Mail-8-715055577
Content-Transfer-Encoding: base64
Content-Type: image/jpeg; x-mac-type=4A504547; x-unix-mode=0666;
       x-mac-creator=43706E74; name=1206-crystal.jpg
Content-Disposition: inline;
       filename=1206-crystal.jpg
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--Apple-Mail-8-715055577
Content-Transfer-Encoding: 7bit
Content-Type: text/plain;
       charset=US-ASCII;
       format=flowed


 :-(
BillW


--Apple-Mail-8-715055577
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

2007\10\06@010818 by David VanHorn

picon face
> > Just don't tell me you used 22pF crystal caps on a 22pF crystal..  :)
>
> Who can tell?  Someone else did schematic entry, and it's one of
> those typical hobbyist projects that says "16 MHz crystal" with
> no further specifications :-)  It does have 22pf caps...

Hmm.  Then the appropriate xtal would be about 16pF or so.
Or bring the caps up to 39pF


> Hmm.  I was happy to get a "ground ring" around the crystal and caps,

Actually, you are VERY close to right.
The track running around this cluster isolates most of it.
I would just add a small exclusion zone around those three pads to the
left, and one to the right of the gnd pad, so that the processor's
ground pad is the only place that this cluster touches any other
ground.

2007\10\08@034541 by Alan B. Pearce

face picon face
>> Hmm.  I was happy to get a "ground ring" around the crystal and caps,
>
>Actually, you are VERY close to right.
>The track running around this cluster isolates most of it.
>I would just add a small exclusion zone around those three pads to the
>left, and one to the right of the gnd pad, so that the processor's
>ground pad is the only place that this cluster touches any other
>ground.

Personally I would have the two inner ends of the caps as the ground
connection, rather than the outer ends as illustrated, making it closer to a
point ground. Without knowing which pins on the micro are the xtal
connections, I also tend to have the xtal mounted parallel to the ic pins,
and the cap ground connections taking the shortest route to the nearest
ground pin.

However, after thinking about it, the layout illustrated may be fine if the
two capacitors are side by side instead of end on, as the lower cap has its
ground end very close to the ground connection on the DIL holes (I'm
assuming that is the micro). If the other cap was beside it then it would
also have a very short ground connection, but at the moment it has a
'reasonable' path around the ground plane loop that is around the caps and
xtal.

2007\10\08@042316 by KPL

picon face
> > Who can tell?  Someone else did schematic entry, and it's one of
> > those typical hobbyist projects that says "16 MHz crystal" with
> > no further specifications :-)  It does have 22pf caps...
>
> Hmm.  Then the appropriate xtal would be about 16pF or so.
> Or bring the caps up to 39pF

Can You explain this a bit more? :)

--
KPL

2007\10\08@132415 by David VanHorn

picon face
> > Hmm.  Then the appropriate xtal would be about 16pF or so.
> > Or bring the caps up to 39pF
>
> Can You explain this a bit more? :)

Despite any microcontroller data sheets to the contrary, the CRYSTAL
determines the cap values.  If a given uC data sheet shows say 22pF
caps, then you're seeing the result of misinformed consumers beating
up the vendor to provide something they shouldn't.  A correctly done
app note will not show cap values unless they also show a specific
crystal part number.  It's up to you, the engineer, to select the
appropriate crystal, and then the proper caps given that crystal, and
your PCB layout.

A given uC may have a preference for crystals of a given impedance and
drive level, but that's a different issue.   The fox application notes
cover this pretty well.

2007\10\09@022424 by William \Chops\ Westfield

face picon face

On Oct 8, 2007, at 12:45 AM, Alan B. Pearce wrote:

>> so that the processor's
>> ground pad is the only place that this cluster touches any other
>> ground.
>
> Personally I would have the two inner ends of the caps as the ground
> connection, rather than the outer ends as illustrated, making it  
> closer to a
> point ground.

Ah, I think I'm starting to understand.  While a ground plane provides
nice shielding and power distribution, "bypass caps" should be wired
directly across the pins of the IC they are bypassing, rather than  
between
a power pin and the ground plane (even if the ground pin of the chip is
relatively close by.)  This helps prevent the transients that are  
produced
by the chip from being propagated onto the ground plane via the  
"infinite
resistor array" effect that Dave mentioned.
In other words, the ground plane is not your ideal power distribution  
plane.
Hmmph.  That's rather inconvenient.  Are there any tricks to  
implementing
this using common CAD packages?  Even if you directly wire caps to pins,
EAGLE will happily fill in the ground plane as well.  I guess it  
falls out
nicely on 4-layer boards, where the inner layers are power planes but  
the
outer layers (and the caps and their wiring) are on the outside.
How does the tradeoff of wanting separate ground planes and power  
connections
go?  It's counter-intuitive that I might be able to reduce EMI by  
deleting a
component side ground plane, for instance, but taking the concept to  
the limit,
that seems to be what is implied...

Are there amateur-level tests that can give you relative EMI info?  
Not exact
values, but "it's better if I do THIS than if I did THAT" ?  Scope  
with a
dipole or something ?

BillW

2007\10\09@092222 by David VanHorn

picon face
> Ah, I think I'm starting to understand.  While a ground plane provides
> nice shielding and power distribution, "bypass caps" should be wired
> directly across the pins of the IC they are bypassing, rather than
> between
> a power pin and the ground plane (even if the ground pin of the chip is
> relatively close by.)  This helps prevent the transients that are
> produced
> by the chip from being propagated onto the ground plane via the
> "infinite
> resistor array" effect that Dave mentioned.

Right.   I try to locate my caps at the chip ground pin, and I route
thin to the cap, and thick to the chip.


> Even if you directly wire caps to pins,
> EAGLE will happily fill in the ground plane as well.  I guess it
> falls out
> nicely on 4-layer boards, where the inner layers are power planes but
> the
> outer layers (and the caps and their wiring) are on the outside.

I watch where the planing is happening,  and either use "no plane"
zones (old dos orcad) or I move the traces around to prevent the plane
from going where I don't want it to.

2007\10\22@015220 by William \Chops\ Westfield

face picon face

On Oct 5, 2007, at 3:25 PM, William Chops Westfield wrote:

> There's ground plane on the bottom, too.

Hmm.  It's come up in other discussions that having ground planes on  
both top and bottom of a board may not be such a good idea, although  
I'm not convinced that the reasons stated are applicable to a small  
and relatively low-current board like this (ATmega168 + FTDI USB/
serial bridge.)  Any comments from the experienced PCB designers?

Thanks
Bill W

2007\10\22@091018 by David VanHorn
picon face
> Hmm.  It's come up in other discussions that having ground planes on
> both top and bottom of a board may not be such a good idea, although
> I'm not convinced that the reasons stated are applicable to a small
> and relatively low-current board like this (ATmega168 + FTDI USB/
> serial bridge.)  Any comments from the experienced PCB designers?

I plane both sides. But I'm careful about how I plane, and what gets
returned in discrete tracks.  I also separate into analog, digital,
supply, and other plane sections.
Selective shoving of tracks keeps max fill area, without letting one
plane touch the other, except exactly where I want them to.

2007\10\22@133716 by Alexandre Guimaraes

face picon face
Hi, Dave

       Can you elaborate a little bit at what drives the decision of what
returns trough the ground plane and what get's a dedicated ground return
track ? Is current the only factor ?

Best regards,
Alexandre Guimaraes
       

-----Mensagem original-----
De: spam_OUTpiclist-bouncesTakeThisOuTspammit.edu [.....piclist-bouncesKILLspamspam@spam@mit.edu] Em nome de
David VanHorn
Enviada em: 22 October 2007 11:10
Para: Microcontroller discussion list - Public.
Assunto: Re: [AVR] Freeduino Board (was kicad autorouting)

> Hmm.  It's come up in other discussions that having ground planes on
> both top and bottom of a board may not be such a good idea, although
> I'm not convinced that the reasons stated are applicable to a small
> and relatively low-current board like this (ATmega168 + FTDI USB/
> serial bridge.)  Any comments from the experienced PCB designers?

I plane both sides. But I'm careful about how I plane, and what gets
returned in discrete tracks.  I also separate into analog, digital, supply,
and other plane sections.
Selective shoving of tracks keeps max fill area, without letting one plane
touch the other, except exactly where I want them to.

2007\10\22@172731 by David VanHorn

picon face
On 10/22/07, Alexandre Guimaraes <listasspamKILLspamlogikos.com.br> wrote:
> Hi, Dave
>
>        Can you elaborate a little bit at what drives the decision of what
> returns trough the ground plane and what get's a dedicated ground return
> track ? Is current the only factor ?

I don't worry about DC current, but I do about pulsed or high
frequency AC current.
The main rule is "put it back where you got it from".

Oscillator crystal caps should ground ONLY to the uP ground pin,
switching power supplies should be treated as current loops between
the caps and inductor/transformer, through the diode. Try to only
attach ground connections out to the system at points where AC
currents will be near zero, like at bypass cap ground pins.  I've been
known to split up a single cap to three, both for ripple current
ratings as well as to keep as much of the HF energy close to the
transformer as possible.

2007\10\22@201430 by Alexandre Guimaraes

face picon face
Hi,

>Oscillator crystal caps should ground ONLY to the uP ground pin, switching
power supplies should be treated as current >loops between the caps and
inductor/transformer, through the diode. Try to only attach ground
connections out to the system at points where AC currents will be near zero,
like at bypass cap ground pins.  I've been known to split up a single cap to
three, both for ripple current ratings as well as to keep as much of the HF
energy close to the transformer as possible.

       Makes lot of sense to me... But.. What goes to the ground plane ?

       Sorry for asking too much but I have always made most of my boards
without a ground plane or just had one bellow low noise, high gain analog
sections. Most of the things I read in the books is related to very high
speed designs and most of my boards have 4 mhz clocks and consume just a few
miliamps. These techniques seems to me to be quite appropriate to be
discussed here. On dense 2 sided boards the only way to have a mostly
continuous ground plane is to use it to route the ground returns but I am
always afraid to make things worse...

Best regards,
Alexandre Guimaraes






More... (looser matching)
- Last day of these posts
- In 2007 , 2008 only
- Today
- New search...