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31  Using Arduino / Microcontrollers / Bypass capacitor placement. on: April 13, 2013, 09:14:27 am
So the pcb I use has the power lines running underneath the IC socket, and I find that the only place to put the caps outside of the direct path i.e.,

Power supply > IC socket> capacitor (sorry still trying to work out how to use software)
Will the cap still work like this ?
32  Using Arduino / LEDs and Multiplexing / Re: Need help: 2 TLC5940 Arduino problem on: April 12, 2013, 01:19:35 am
I recently had a similar accident (slipped with a oscilloscope) and had all light lit an nothing else.
I left it for a few days the redid the wiring. and it looks to be working again.
Im using breadboard and suffered a combination of shorts and loose connection.
Not understanding modern tronics I assume I tripped an internal fuse and had to re set it.
33  Using Arduino / General Electronics / Re: Home built microcontroller - capacitor question on: April 11, 2013, 02:21:37 pm
I had the same but with ebay I just ordered 50 of them for 99p
I only need 3 but as it was cheaper to bulk them I now have spares.
34  Using Arduino / Project Guidance / Re: Beginner Seeking Beginner Resources on: April 10, 2013, 12:34:09 pm
Try writing it out as a series of blocks in a flow diagram then translate each block.
I'm following a guide for the TLC5960 which explains how to convert a data sheet into code and i'm surprised how easy it is to do.
35  Development / Other Hardware Development / Re: Arduino 1.0.1 causes Mac OS X to crash regularly. Ideas? on: April 06, 2013, 11:51:55 am
Currently running version 152 on OSX 10.8.3 with no problems.!
36  Topics / Product Design / Re: Atmega 328 and TLC5940 routing on: April 03, 2013, 12:18:58 pm
In one diagram I see them placed between the + supply and the VCC pins

Wrong.

Quote
and another diagram put across the + & - supply lines.

Correct.

The capacitor is connected from (A)VCC to GND as close as possible to the chip.


Thats what I thought, thanks.
37  Using Arduino / Project Guidance / Re: Labeling: Have any tricks/tips for identifying your DIY PCB's pins etc.? on: April 03, 2013, 12:25:23 am
Why not print out the board layout with all the pins labelled on it?
That way you can put the unlabelled board next to the printout and see exactly what goes where.
38  Topics / Product Design / Re: Atmega 328 and TLC5940 routing on: April 03, 2013, 12:21:29 am
Even more confused. now with bypass caps.

In one diagram I see them placed between the + supply and the VCC pins, and another diagram put across the + & - supply lines.
Which one is correct?
39  Topics / Product Design / Re: Atmega 328 and TLC5940 routing on: April 02, 2013, 11:29:30 am
My pcb is a varient of the trihole pad design but has two tracks made to run under the chips as supply lines. Would it be ok to put it across these lines at one end of the chips? or should I hide them under the ic sockets as close as possible to the chips power pins.
40  Topics / Product Design / Re: Atmega 328 and TLC5940 routing on: April 01, 2013, 12:51:18 pm
?? not on here?

http://arduino.cc/en/Main/Standalone

Stupid additional question but I plan on running this of a 3.6v PSP battery (always have 2 spare in camera bag + 1 in each of my psp1001 consoles)

Am I supposed to change some component values?

Stupid question and you have permission to roll your eyes.
41  Topics / Product Design / Re: Atmega 328 and TLC5940 routing on: April 01, 2013, 12:21:00 pm
Quote
and added the bypass to the tlc5940

The processor also needs them.


Where? i haven't seen one any ware?
42  Topics / Product Design / Re: Atmega 328 and TLC5940 routing on: April 01, 2013, 07:01:39 am
I prefer DipTrace, and I've been using it for the last year for my personal projects. I know Eagle might be more powerful and has a gigantic user base, but I like DipTrace better. The free version is great and should be enough even for more advanced hobbists.

Back on topic: ditch that layout, since there are several problems with it:
- the crystal is too far from the 328
- there are sharp corners in the traces. Never, NEVER route traces with 90ยบ angles.
- there is no bypass capacitors for either chip
- it is good practice to use every space left in the board (in its signal side) for a copper pour linked to the ground net.

If you decide to go ahead and use that circuit anyway, that one is easier done with a perfboard, rather than etched. Make use you use DIP sockets, instead of soldering the chips directly to the board.

I have moved the crystal under the board and added the bypass to the tlc5940
Still playing with layout designs.
Need to order some electronics to check out part size's
43  Topics / Product Design / Re: Atmega 328 and TLC5940 routing on: April 01, 2013, 02:09:39 am

Crystal is rather far from the processor.  I believe Atmel recommends as close as possible with a ground plane.

No bypass capacitors?

I believe the TLC5940 datasheet calls for a capacitor of several microfarads across VCC and GND.


Now that I missed because I didn't see a referance for it on the sheet (still trying to understand it tbh) but the arduino prototype doesn't have one.

Codelink - still building the schematic for this  smiley-eek  smiley-cry
44  Using Arduino / Project Guidance / Re: Atmega 328 crystal location. on: April 01, 2013, 02:06:58 am
Thanks DigitalRS and Cross roads.
I was still working in single layer format!
I think I will go duel layer and add it under the mega chip.

Thanks for the interference info, that was what I was looking for.
45  Topics / Product Design / Re: Atmega 328 and TLC5940 routing on: March 31, 2013, 03:08:41 pm
Well Eagle is so unfriendly it's crap, without a ton or reading I cant even get started.
Fritzing keeps putting things in the wrong place.
Screw that where my copper clad stripboard.
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