They are needed to deal with the large current peaks on the different supply leads.
http://img407.imageshack.us/img407/6971/11111111je.png
http://img844.imageshack.us/img844/5672/22222222l.png
Here it is. I appreciate your help. But if there is something wrong with my board can you be more specific.
I really want to fix it and make it work so that would help me a lot.
your blue layer is getting whorse. The long lines to capacitors are coils at high frequencies.
And your schematic is still wrong:
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each uC Vdd should be connected to positive power supply
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each uC Vss should be connected to negative power supply
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for each Vdd/Vss pair, add a capacitor connected to Vdd and Vss.
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each capacitor sould be placed few mm of uC pins, let say max 5mm
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fill blue layer of copper and connected to vss, so each capacitor is connected to Vss with less than 1mm connection.
Angelo
Your layout seems to be getting worse, and you seem incapable of applying what you have been told on several occasions. I’d abandon this board and learn PCB design with something much simpler; this is going to take months at this rate!
I just can’t f-ckin get it… I searched the web, I read a book, but still I don’t understand what you mean. In my stupid physics book there is nothing mentioned about all these things you guys are talking about. I guess because in their imaginary world things work like an utopia. Nevertheless I want to construct this pcb, does anyone have .brd which I can take a look at?
Self quote :mrgreen:
Polux rsv:
your blue layer is getting whorse. The long lines to capacitors are coils at high frequencies.And your schematic is still wrong:
each uC Vdd should be connected to positive power supply
each uC Vss should be connected to negative power supply
for each Vdd/Vss pair, add a capacitor connected to Vdd and Vss.
each capacitor sould be placed few mm of uC pins, let say max 5mm
fill blue layer of copper and connected to vss, so each capacitor is connected to Vss with less than 1mm connection.
Angelo
It could not be much simpler. Post your schematic.
Angelo
Sorry for the awful layout, I am self-taught and I got no clue on how to make it better… hope you understand it.
http://img94.imageshack.us/img94/7808/97954250.png
Also answer few of my queries about the things you advised me to do…
What is a uC? What do you mean by “for each Vdd/Vss pair, add a capacitor connected to Vdd and Vss.”, for instance take the 2 pins of vdd and both connect them to the same point of the one capacitor end and than connect the capacitor to battery?
“fill blue layer of copper and connected to vss, so each capacitor is connected to Vss with less than 1mm connection.” How can I do that on eagleCAD? I found a tutorial like 1 month ago, asked here if it was a good idea, and ppl said I shouldn’t do it.
Drawing a proper schematic would help, no one is going to waste time trying to decipher that rubbish!
easy thing to say but HOW?leon_heller:
Drawing a proper schematic would help, no one is going to waste time trying to decipher that rubbish!
d4n1s:
easy thing to say but HOW?
Learn how to walk before you start trying to run. You are way in over your head right now. Start with much simpler circuits first - there are some tutorials here; “Beginning Embedded Electronics” might be a good place to start:
http://www.sparkfun.com/tutorials
However, if you want to really make some progress you need to forget you ever said “I have understand that the best way to learn is to start from hard things. Step by step will get you boring!” Did you ever learn how to swim? 
Look at some schematics, like those for the ARM boards sold by Sparkfun, and try to produce something like them.
thx for the tutorial, it took me like 1 hour to fix my schematic thought… Here it is 
http://img840.imageshack.us/img840/2842/schematicx.png
Now that you have the schematic… what am I doing wrong?
I give up. :oops: 
Angelo
why? What I done wrong again?!?
You lack basic electronics knoweledge !!!
How would you make running the LPC2138 connecting capacitors in series on Vdd and Vss lines.
Re-re-re-re-reread my previous posts on how to connect powersupplies.
As anybody said in this post, try something simpler. Let say a plain old NE555 wich blinks a led :mrgreen:
Angelo
Perhaps we should have told him that the circuit and PCB were fine and he could go ahead and order his PCBs. He’d learn a salutory lesson when they don’t work.
leon_heller:
Perhaps we should have told him that the circuit and PCB were fine and he could go ahead and order his PCBs. He’d learn a salutory lesson when they don’t work.
Like don’t trust ppl on the internet? Anyways guys, I am trying my best, so please don’t disappoint me, I connected the capacitors in pairs just like you said…
The connections are wrong, though.
Because I am having a serious headache!!! I think we can’t communicate… I look at schematics, they don’t have capacitors on pairs , they don’t have capacitors on vss pins and they dont have capacitors at VDD pins…tell me what is wrong with my schematic… You just say the connections are wrong, or it is too messy but you won’t tell me what to do to fix it…Let me exclude angelo’s attempt which was really appreciated…
Schematic http://www.megaupload.com/?d=VMLRWL57
Try connecting Vdd to the Vdd pins, and Vss to the Vss pins! You don’t need to decouple the Vss pins.