Urgent!! Ain Module Problem

[sidetrack]

Ok so here's the deal, I have my MIOS uploaded, mb64 app is uploaded.  I have hooked up the LCD and AIN to the core.  I have only one pot hooked up right now, the problem is that even though I have clamped all open analogue lines to ground (I clamped three 4051's to ground before the IC 's so I wouldnt have to do all the analogue inputs, and I have the open lines on the first 4051 clamped) the LCD is still reading lots of information constantly from what appears to be mostly #16 and #15, although it sweeps down to others occasionally.  I have checked and rechecked all the solderings and they look fine. 

I'm stumped! 

When I get home I'm gonna try switching out the 4051 with another to see if its damaged, but other than that I don't have a lot of options running through my mind.  I was told that using a DC output wallwart into the core module could make it unstable and is perhaps causing this, Is this true?? and if yes what do I bypass in the circuit?

Please help! I am on a tight deadline so any suggestions will be gratefully accepted.

Thanks,

Ryan

[moogah]

I've almost never found a dead IC in a year of working with this stuff, I always suspect some mistake I made first.  I would suggest starting right from the beginning today, see if you can find some detail that doesn't seem related at the moment.  Assume that everything you did is wrong and read the schematics and layouts again.  Often that is where I go "AHA!".  If not, you can get a rough test on your power line with a meter, check that the DC voltage before the regulator is 7-10v and the output is a nice steady 5v.  If you've got that then go ahead and check the power pins on the AIN module to be sure something isn't getting messed up there. 

I don't know about any specific issue with a DC wallwart causing trouble, search the forums on that one.

(I clamped three 4051's to ground before the IC 's so I wouldnt have to do all the analogue inputs, and I have the open lines on the first 4051 clamped)

I would carefully double and triple check that the way you did this is correct, it at least could cause your problem.  I say this assuming that you mean that most the activity is coming from pots 15 & 16, and IIRC they are assigned to the second 4051.  The schematic shows how to do it, I assume you did it the same way?

[sidetrack]

I will go in with the magnifying glass and check the second 4051's analogue lines for soldering errors.  It would make sense for the error to be there. 

I have tested my wallwart across several places on the core module and found it to be a steady 5.7 v (i think).  I will try and test it on the AIN to make sure it is receiving the same voltage. 

I had a thought just now, it might be stupid and wrong but thats what being a noob at this means! Do I have to clamp the unused Analogue inputs on the core to ground as well?? I'm using A0 right now, so that would mean A1-3. 

Anyways thanks for your suggestions I will get on that as soon as I get back home.

Oh and if someone could answer my question about the DC input into the core that would help because I have had someone tell me that it would make my system unstable.

Ryan

[audiocommander]

I had a thought just now, it might be stupid and wrong but thats what being a noob at this means! Do I have to clamp the unused Analogue inputs on the core to ground as well?? I'm using A0 right now, so that would mean A1-3. 

Yes, you should ground all unused pins, including those from the core.

If you have one AINx4-board hooked up, you should have A0 to A3 connected. So A4 to A7 are free and to be grounded.

Check TK's reminder here:

http://www.ucapps.de/mbhp/auaimbctg.pdf

I'm sure your issue will go away when you ground the remaining AIN pins on the core ;)

Best regards,

Michael

ps: When some random data is received, I made the experience that you cannot rely on the pin numbers the application gives you. So don't give too much on pins 15 and 16; the error can also be on any other pin before or after.

[sidetrack]

Thanks a lot audiocommander, that totally makes sense.  I will do what you said and come back with my results.

Ryan

[sidetrack]

Yes! I did it, and it works like a charm.  Goddamn its beautiful.  Incidently I have hooked up one button as well, and it works!.

I am on my way to finishing this project, I will create a new thread when I am closer, and I will post all the pictures I have taken during the process, as well as my design document so that others may build it!.

Thanks for all the help

Ryan