Xilinx SP605 DDR3 Allegro 15.7 Viewer Questions

Sat Sep 24, 2011 8:40 pm   

I am designing a Spartan-6 pcb with DDR3 by way of Memory Control Block and
with various video interfaces. Before I start with my own design, I thought
I would look at other available designs, including the Xilinx SP605 design.
I downloaded the design files and opened file 4199_SP605_brd_091909.brd with
Allegro's Summer '09 viewer, that is, v15.7. There are top, bottom, and four
inner signal layers that are nicely viewable by manipulating the display
enables and colors. You can click on the info button to get net information,
a clear advantage over Gerber files. I'll post some questions about the
routes on these signal layers later but now I have a question about the
inner power plane layers.

These inner plane layers display as completely filled areas with no regard
to vias. All the vias appear to connect to the planes whereas it's clear
that a high proportion of vias should not. Now I'm an old EAGLE user and I
remember that I had to click on the ratnest tool in order to get the polygon
fills to "render". But I don't see any comparable button on the Allegro Free
Viewer. Is it possible to get these via connections to show properly?

Another issue is the plot. I can plot to my printer, that's good. But when I
plot to a file, the file has a .PLT extension. I've already tried
TotalCADConverter to get this into another form, a .BMP file, which did not
work. All I got was one long line. Has any one converted these .PLT files
successfully with free software?

Thanks in advance,

Brad Smallridge
Ai Vision

Fri Sep 30, 2011 9:14 pm   

OK, well I have updated to v16.5.
Nice improvement in the colors and such.
But I can't see the vias as being
isolated from the copper pours.

Sat Oct 01, 2011 8:17 pm   

Brad Smallridge wrote:

With v15.7 :

Turn off everything else:
display->color and visibility->global visibility->all invisible

Turn on the etch for the layer you want to see:
Visibility Tab-> 07_Pwr2 etch checkbox

Enable display of Thermal Pads:
Setup->Drawing Options->Display->Thermal Pads

This should show you a circle/circle-with-spokes/solid connection
for each via.

Note that this setting will "hide" the normal colored-if-connected
display of vias whenever the etch display is turned on.


IIRC, PrimoPDF worked for me a few years back to print to a pdf.

HTH,
Brian

Sun Oct 02, 2011 1:46 am   

Beautiful. Well worth reinstalling the 15.7 viewer again.
I uninstalled the 16.5 but maybe I didn't have to do that.
I did not see any similar option on the 16.5 viewer.


I don't follow this.


I will try this if I can't find something else. I'd like to be able
to edit the images in something easier, like a JPEG. My backup is to
print onto paper and rescan.

Thank you so much Brian,

Brad Smallridge
Ai Vision

Mon Oct 03, 2011 12:38 am   

Brad Smallridge wrote:

They seem to co-exist OK, the default 16.5 install directory
differed from 15.7's when I ran the 16.5 installer today.


Looks like it has been moved to:
Setup->Design Parameters->Display->Enhanced Display Modes->Thermal
Pads


The boards I used to review from the local layout houses were
generally set up with different net color assignments for the
power nets ( instead of the all-white theme of that SP605 board ),
so displaying just the vias on a power plane would show a
constellation of differently colored donuts for the power vias,
and light gray for everything else.

Particularly on power planes that haven't been poured yet,
this makes it very easy to eyeball split plane cuts.

But when you have both vias _and_ the layer etch turned on,
_and_ that "thermal pads" option is true, this colored-donut
view is hidden by the thermal relief rendering.

[ It's been a few years since I've actively used that viewer to
review
design files, so my description above might be slightly mangled ]

To see this effect, try using the Display->Assign Colors in 16.5 to
give some of the power nets a different color on that SP605 board.

Brian

Mon Oct 03, 2011 1:29 am   

Looking around the 16.5 menus, I spotted the following command:
File->Capture Canvas Image
that can save the current board view to a JPEG file.

Brian