Amega328p-au shorted pins ?

Hi James,

James Zelazny jr wrote:

 

Finally motivated myself into trying Eagle files only to see my original instincts told me NOT to bother.

I get it you are feeling frustrated, the first time I tried to use EAGLE it didn't go so well. I had to sit down and read the manual and tutorials to understand how it works as previously I had spent a lot of time with DxDesigner/PADS and OrCAD, and EAGLE was quite a change from both of these.

James Zelazny jr wrote:

 

The last thing I expected was not finding common components in the library.My first mistake to assume that an Atmega328p-au would be one of the easiest to find.Not so and had to search the ends of the earth to find it and manually place it into the LIBR directory.After a 4 hour search and finally having this IC in my schematic layout

So the issue here is assuming the bundled parts library is useful. As with the "free" parts libraries that are bundled with absolutely all ECAD packages, not just EAGLE, you get what you pay for. If you value your time and the integrity of your designs you'll just create your own libraries. It's actually quite easy once you've done a few parts. There are great tutorials to get you started on Adafruit and Dangerous Prototypes. To start this from scratch and do it properly yourself would have been a fraction of the time you spent searching.

James Zelazny jr wrote:

 

.After a 4 hour search and finally having this IC in my schematic layout I now see "shorts" on several pins of this chip in the BRD window.The worse possible places no less on 3.3v and ground !!

I can probably modify this file but now getting far deeper into a simple project I thought would be straight forward.

Is it a software glitch causing this or a bad library file ?

Anyone know where to find a working Atmega328p-au footprint

See attached screen shot of the issue.

It looks like it's just showing air wires between pins on the same net, not between nets i.e. it's connecting all the GND and separately all the 3.3V but I am a little perplexed why as it doesn't look like you have any nets added on the schematic and dropping in a part with multiple pads on the same pin of the part doesn't show air wires for me until I connect up a net in the schematic. Could you put the lib/sch/brd files up on here so we can take a look at what you have done please?

Best Regards,

Rachael

The screenshot is just me adding the very first component into the work space.I did nothing but add the library file for the Atmega328p-au,started the program and was the very first component selected.I did nothing but check the board view to find these pins already wired.

I spent an entire day downloading as many components for my project as possible and had it just about completed on the second day when I discovered many wires in places that should not have been.So,cleaned the slate and even re-installed Eagle and started over.

This time I wanted to place a component and do little at a time while checking for bogus traces.That is when I finally discovered these connections right off before even starting the project...just merely adding the component and this shows up.

I also would like to note that sometimes the program crashes and will lose my work unless I save each and everything I do.

Frustrated is a mild term at this point.

So basically,I open the program,create a project and the first thing I do is select the Atmega328p-au and put it into the schematic work space.and that is what I am getting.I have done nothing else

Here is the file I used and wonder if it is just a bad file itself ?

https://www.snapeda.com/parts/ATMEGA328P-AU/Atmel/view-part/

Give it a try and see what you get ?

Just to update my progress,I have seemed to be learning a bit and progressing with this project.

The DRU files from Ohpark loaded seemed to help greatly.

Also zeroed the NET CLASSES using default.Eventually they are set to 5mil.

So the above issue from that link was great help as well.

After some minor issues was able to produce a BRD file to upload to Ohpark.I get ZERO DRC errors now and the Si5351a chip (U1) finds traces like it should.

Now to look over and double check everything and build a bread board design for programming and testing.If all goes well,will order a few PCB`s and try my hand with SMD.

Board - https://644db4de3505c40a0444-327723bce298e3ff5813fb42baeefbaa.ssl.cf1.rackcdn.com/09256ea28b82b0e705c19685ab301150.png

Bottom - https://644db4de3505c40a0444-327723bce298e3ff5813fb42baeefbaa.ssl.cf1.rackcdn.com/2c687c3b7069769618305c3053786940.png

Thank you here for all the help and patience.

Jim

Hi James,

I'm glad you are learning and making progress Hopefully you are finding it more rewarding now you are starting to see some results. I just had a quick peek at the two images you posted up. I have a couple of comments.

Firstly, your power net is routed around the board with a really skinny trace. I wouldn't recommend this, especially as you don't appear to have any decoupling caps at the IC pins. I think this is likely to end up being problematic. If it were my board I would try and use polygon fills top and bottom to get your Vcc and GND connected around the board as much as possible. Obviously with a 2 layer board you're going to end up cutting up any polygon fills with all the other traces running around but I would give this a try to see how it works.

Secondly, it's obviously auto routed and there are several places where the nets just go really close to things when there is bags of room for them to have a little more clearance. Examples would be the traces running very close to X2 and the ones around J1 but there are plenty of examples all over the board. I'd recommend you have a go at manual routing on the board, you'll pretty much always get a much nicer result.

Best Regards,

Rachael

I moved to my programming issues for the time and was worried because after all...if I can not program the 328 it is useless.

But yes on your comments in regards to the traces running long.I was just happy to get a BRD file and test it out

I can now move stuff around and tighten everything up and add or remove other components.

The schematic is designed around an existing circuit and using identical components.I do see room for decoupling caps to the 328 IC.

I have not used them in previous build except for the GPS and Si5351 for the obvious reason the y produce RF.I had issues in this regard and is why they were added and the circuit runs well as it is.But to be safe,maybe I will add them to the 328 too.

I was not too worried about the power traces being so small since the input voltage will be merely a 3.7 lipo @ 100mah then into the 3 voltage regs for an output of 3.3v.I used 3 regs for each module,328/gps and si5351 as to not stress one for everything.My previous build was using 5v directly from 5v boost module from a lipo 3.7v/100mah battery.No voltage regulators except the onboard regs of the 5351 and GPS.The 328 IC was ok since it runs 5v max anyhow.This board was to emulate the identical circuit only eliminating the 5v boost module to reduce weight and components needed.

My GPS modules arrived and weigh only .9 grams where the prebuilt GPS is like 7 grams.The Si5351 prebuilt for 5v weighs about the same and that has be drastically reduced as well.So big time gains regarding weight loss on this.

I should mention it also will have solar cells attached.The battery and solar input have 3 connections one for batt and the other for solar cells.

Added a blocking diode between batt/soalr to prevent voltage from absorbing into the cells.It seems to work great that way.

The cool part is the batteries I buy are tiny and have a built in over charge circuit...ready to use.

Thanks again for you assistance and comments.VERY helpful and will come back to post my revised board and maybe a working board !!

Setup a duplicate of the circuit on bread board to run a test.It will be a first using 3.3v rather than 5v.

I had to change one of the 328 fuses to do this and that is about it.

So far,it started without issues.Waiting for a clean calibration by GPS which takes some time.

No RF issues causing problems even with all the wires sticking up.

This is a good sign.

Firmware looks like it uploaded properly.

Jim

To end this topic on a fair note,the boards came out pretty good for a first time effort and were assembled.

Even though the first worked well,it had a few errors one being a choke improperly placed and not grounding both pads for the antenna output.

This board was launched on 2 x 36" party balloons and soon discovered a very bad signal.It faded off earlier than it should have and called it a loss once it vanished over 300 miles from my location over the Atlantic ocean.

To my surprise,it showed up again over 10 days later after traveling around the earth.It managed to fly close enough to a listening station and was heard only a handful of times that day.The following day it showed up again over Michigan and again lucky to be heard by only 2 more stations briefly before flying up into Canadian territory North bound.

Who knows,maybe it will show up again.

Just wanted to share my Eagle file build as a pretty good end to this project...for now.

Details -

http://qrp-labs.com/flights/u3s8.html

Jim

Hi Jim,

Thanks for coming back to give us an update, it's really nice to hear back about projects like this, it's a shame you had other issues which affected your ability to track the balloons properly but it worked and so I think we can definitely consider this first effort with EAGLE a success

So what projects do you have planned next?

Best Regards,

Rachael

Rachel,

Thank you for the positive feed back.

Still working on some boards sent to me by a friend that are much better design.But hope to revise my own again soon.

I made an attempt last week to launch an identical board and it went into a tree several houses away.It was operating by solar power for a week on and off,survive wind and some rain and still kept working.Patiently waiting for it to drop from the tree,today I witnessed it break loose and drop to the ground in the gusty winds.I have recovered it and will test it for another try.I now have 4 ready to fly hopefully this weekend.

Hard to believe this payload survived  INTACT for a week until today where it was only solar cell damage.

Certainly reusable and working on that now.

Jim

Just for FYI,a website was started with details of this circuit and hobby - radio-signals forum – radio-signals.com

Jim

Been some time and have made great progress with help from this group.

Thanks to Rachel and others for your patience and help.

I have since taken a long break from these circuits but had a lot of fun and interesting flights using them.

My last PCB was much smaller a friend shared with me and almost flew it around the earth twice.It lasted 63 days in the sky floating all over the world.

I am posting this as I share this with others also wanting to design,build and fly these projects and hope they get something from it.

https://www.qrp-labs.com/flights/u3s22.html

Jim

What a journey for both you and the project.

Thanks for sharing the ups and downs,

What a journey for both you and the project.

Thanks for sharing the ups and downs,