Go Down

Topic: ATMEL Mega1284P evaluation board avalible (Read 178439 times) previous topic - next topic

mowcius


CrossRoads

I got close! 45 not so handy with a long rectangular board.
Besides, long parallel runs are good for inducucing crosstalk between signals, so is better to break them up.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

retrolefty

Came across this on the AVRfreaks site. Some kind of bug with Mega1284p on serial RX0 requiring a low pass filter to solve. Don't know the root problem or even the symptom seen, but this seems to be a fix:

http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=107115

Lefty

skyjumper

I have a prototype board Crossroads made up originally for the 644P-DIP, and I have since replaced the 644P with a 1284P in DIP. My application is heavily serial based, although with the second serial port. Tonight I will write up a little code that moves data out the first serial port at high speed and see what happens. I know the second serial port is fine as it ran for nearly five days with no errors.

I doubt I'll have an issue though.


skyjumper

Bob, I suggest on the 0805 parts you switch from package 0805RND to 0805. I have asked around and not received much feedback on the parctical difference, but the square pads have more surface area for solder paste to flow on. The few opinions I were offered went in favor of square pads. When I had my stencil made, the maker thought he was doing me a favor and removed the round pads because he though they were holes. He is making a new one now.

Over all it may be a small change but its easy to make and I think worth the effort.
 

skyjumper

Okay, my 1284P DIP is dumping data out Serial at 115,200 with no end in sight. We'll see if it keeps going.

skyjumper

Looking at parts for availability next - checking the SD socket to see if make can go in (digikey carries several, the mechanical drawings are not the easiest to interpret) or if the Sparkfun library part is unique.


I have searched, and as far as I can tell, the SparkFun SD Socket is available only through SparkFun or its manufacturer. The maker is a company called 4UTechnology and they will sell these direct, but its not super clear how to buy them. Through SparkFun its about $4.00, which is very high.

On my prototype, this is the first thing on the list to change for production.


48X24X48X


Looking at parts for availability next - checking the SD socket to see if make can go in (digikey carries several, the mechanical drawings are not the easiest to interpret) or if the Sparkfun library part is unique.


I have searched, and as far as I can tell, the SparkFun SD Socket is available only through SparkFun or its manufacturer. The maker is a company called 4UTechnology and they will sell these direct, but its not super clear how to buy them. Through SparkFun its about $4.00, which is very high.

On my prototype, this is the first thing on the list to change for production.




Those connectors are from 4UConnector. They are not a manufacturer but a some sort of huge connector trading company. You can the connectors way cheaper there. You can get samples something like for 10 pieces. But, they expect you to buy in reels later on. I think it's best to stick to some easily obtained manufacturer like Molex and the like.

CrossRoads

"I think it's best to stick to some easily obtained manufacturer like Molex and the like."  Yet there no library symbols for those, or maybe there are & I'm just not clever enough to have found them yet.
I'd like to go with the FCI connector that Digikey carries, one of the better prices, the thickest gold plating on the contacts, and what looks lke a decentmetal housing. I haven't figured out how to make symbols yet to be able to add it into a design.

I''ve finally got the Clearance errors cleaned up on my hand routed board.
Got a pile of drill size errors now, not even sure what the fix is for those!
And then back to the Stop Mask errors and Width errors.
Pain in the ass.  The auto router made some errors; this is ridiculous.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

skyjumper

#129
May 24, 2011, 08:49 am Last Edit: May 24, 2011, 08:51 am by skyjumper Reason: 1
So far about 2.5 hours of serial data moving around, no issues (knock on wood).

sixeyes

Quote
I haven't figured out how to make symbols yet to be able to add it into a design.


http://www.instructables.com/id/How-to-make-a-custom-library-part-in-Eagle-CAD-too/

Does this help?

I use this every time I can't find the part in Eagle.

CrossRoads

@sixeyes,
I can give it a shot. What'd I'd really like is to just be able to mod & save the existing socket - it really just needs the pads moved left & right a little. Is there an easy way to do that?

As long as I have your eyes - my hand routing resulted in a bunch of drill size error. Something about 0.012" vias on traces that are 0.01 wide, which appears to be the size that eagle uses when it autoroutes. I opened the vias to the first standard size listed, 0.019xxx, the DRC with Fusion rules checker still calls them out. I don't know what to do fix it.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

tastewar


...
As long as I have your eyes - my hand routing resulted in a bunch of drill size error. Something about 0.012" vias on traces that are 0.01 wide, which appears to be the size that eagle uses when it autoroutes. I opened the vias to the first standard size listed, 0.019xxx, the DRC with Fusion rules checker still calls them out. I don't know what to do fix it.


Coming at this from a position of blissful ignorance (so please just ignore me if I'm sounding stupid), it sounds to me like Eagle is complaining that the via's are too big, and it sounds like your action ("I opened the vias to the first standard size listed, 0.019xxx...") was to make them bigger (compared to 0.012). Perhaps they need to be made smaller? Or the traces made bigger??

sixeyes

Quote
What'd I'd really like is to just be able to mod & save the existing socket - it really just needs the pads moved left & right a little. Is there an easy way to do that?


Yes you can do that too. I tend to copy libraries and edit them, more than create new parts. The link shows you how to create a new part but the instructions can be applied to existing parts.

CrossRoads

@tastewar,
I can't tell if too big or too small or a conflict with the trace width - it just lists Error as "Drill size" and the layer; thenI click it and it shows where on the board. No explanation.

You'd think that having 2 standard selections would make things legit.

I guess the DRU file, that we got from Seeed Studio I think as a good example, is doing me in, but I don't understand it enough to know how to fix things. Clearances, that was straightforward. There's also "Width" errors, for a trace sitting on a pad - what's the matter with that? 
I won't get a  chance to do anything until 10:30ish (east coast) tonight.

Can't even autoroute it anymore - design is too complex, it only get ~72% done  then chokes.

@sixeyes,
Will play with the symbol then too.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Go Up