WTH.....PCB prototype missing nets in hardware......arrrrrrrrrrrrrr

[kittmaster]

I'm really, really, really not happy.....at all...beyond mad. Keep in mind I've already BUILT AND POPULATED a prototype > at least 7 hours of work.

My embedded controller is using a max232 for serial, a 74244, 74138, 74373, 74hc541, and 74hc574 for logic control. And the MPU for system operation

ALL of these parts are listed in the database and show up in MS except the MPU. Now what angers me the most is that the power pins are not shown unless you symbol edit it and force the pins to be shown.

Now, when I hooked it up, transferred to UB, all the VCC's where connected (which is why I built it, was the first thing I looked at, first glance seemed good with 500+ nets). What I didn't pay attention too was the GROUNDS. NONE OF THEM WERE NETLISTED.....so I'm thinking WTF, come to find out all of these parts are internally referenced to the net name "GND" and in MS's infinite wisdom, the DC POWER GROUND SYMBOL IS ASSIGNED NET "0". Hence why no grounds where connected.

So let me get this straight, it hooks up the VCC rails corrected but all the ground pins are disconnected...........WHYYYYYYYYYYYYYYYY?

So if I double click a single MS component and change net GND to 0, it reroutes and my forward annotate now assigns ground to the modified component net.

Now, this might be great for a single component. I have 50 plus IC's spanning multiple pages and I sure as hell don't want to have to do this dog and pony show 50 times, so for each page I select all the components, right click, viola, the same options as a single chip edit, so I change GND to 0 hit, OK, and bingo........IT REMAINS AS GND.........ARRRRRRRRRRRRRRRRRRRRRRRR..........I can't take this anymore......I'm at wits end here. This is just plain stupid.

Anyone have any constructive advise before I throw my pet brick through my monitor?

[lacy]

Don't know if you have already done this or not, but here it goes. Under SHEET PROPERTIES>PCB there is an option labeled "Connect Digital Ground to Analog Ground". You might want to be sure that the box beside it is checked.

I don't know if this will solve your problem, but it couldn't hurt to check it out.

[kittmaster]

this is always a dangerous option, I guess in a digital scenerio its no big deal, but if I had an op amp or something in there, it could lead to disaster.......I'll give it a try to see if that does it.....

[kittmaster]

Lacy,

Yeah, when I check connect analog and digital grounds together, it actually REMOVES net zero completely and reassigns it to GND.

I'm sure I could rename net 0 in the future, but this is dangerous layout behavior since things today are no longer strictly analog (amplifiers) or strictly digital (counters) and in a mixed mode environment, dropping a small signal reference point to a digital noisey ground spells disaster.

Of course the help file is useless, just say yeah go ahead if you want to connect them, no warning of how the autorouter is going to see this or handle the routing priority since they are just a singular net now.....hmmmmmmm

[lacy]

I can understand what your saying about it being risky and I would prefer to keep things like that seperate as well just to be cautious, but I couldn't think of any other options in this case. There is probably a way to accomplish this that we just can't find at the moment.

[kittmaster]

I don't know if this a "feature" or a bug.....either way the arguement is both valid and invalid at the same time.

Both analog and digital need to be grounded. But for the suite to NOT connect and/or warn that these pins have no connection..........


YEAHHHHHHHHH that is what is needed and UNCONNECTED pin report for MS unconnected pins......right now there is a feedback of unconnected pins in the schematic statistics, but it doesn't explain WHICH pins are unconnected.........this is dodgy at best.

I think there should be a features added for the USER to tell what the DRC should check for in both MS and UB so this type of mess doesn't happen.......hell tango 2.3 DOS!! > had this as a feature....that was 15 years ago!

Food for thought NI??.....maybe

[lacy]

I just tried a circuit with both analog and digital grounds and according to my netlist I have 2 nets. One is labeled 0 in reference to the analog ground and the other is just labeled GND in reference to the digital ground.

Also on this slapped together schematic I had VSS also and it showed up as a separate net from Net 0 and GND. Most IC's that I have seen use VSS to designate thier ground instead of the DGND or Analog ground and when I exported my circuit all the VSS Sources were tied to their respective pins between components.

Unless I missing something here it would seem that on my Multisim it is exporting all grounds as separate and Ultiboard is assigning different Nets to each. So I do not know at this point what to make of this situation.

Message Edited by lacy on 11-22-2007 12:04 PM

[lacy]

Maybe by editing the component symbols to make the power pins visible has somehow created this situation. This is just a thought and I can't say for sure that is what happened, but it seems resonable based upon what I did in my last post. I just trie an export of your first IC on the list and it tranfered and hooked to the GND Net and not the Net zero. So I really at this point don't have a clue as to why your having this problem.

Message Edited by lacy on 11-22-2007 12:16 PM

[kittmaster]

You are right in that all 0's and GND are exported seperately. Hence the ultimate problem, at some point VSS, 0, DGND and GND must reconnect to the reference point of the circuit. IN my case this is the - terminal of the battery, under these conditions that is not happening, only nets attached to 0 are begin tied to the negative supply. All the GND's are attached, but do not connect to net 0 (which makes sense). This is because I would have to manually right click on the component > pins > force GND and rename it to 0. This works, but its a texas two step.

For onez twoz circuits......not a big deal, but for 100+ components......that is where my issue lies.

[lacy]

O.K. I understand now. I was thinking that the nets weren't getting exported and were missing. I apologize for not understanding totally what was happening. I don't know of any other way around this other than the analog/digital ground setting in Multisim, but as you point out this isn't working the way it should either.

Well, I have exhausted everything I can think of. Maybe the NI Team can come up with a workaround. I think this needs to be put of a fix list as I would definitely consider this a bug.