Go Down

Topic: ATMEL Mega1284P evaluation board avalible (Read 81718 times) previous topic - next topic


Well, I cooked up a board. The things a break at Christmas is good for. :)


Cool...  I want one  :smiley-mr-green:  

Hey but can you break out the rest of the pins??  You could make a 2-wide header that goes along an edge, kind of like Maple.

What is the big pad around U1 for?  A heat sink?  

#451
Dec 30, 2011, 09:19 pm Last Edit: Dec 30, 2011, 09:24 pm by adilinden Reason: 1
My primary objective for the 1284P is to get the additional RAM (and code space). Also needed to maintain the traditional Arduino dimensions and header locations, including ICSP. There is more then enough IO on an ATmega328 for my purposes.

When I thought out the board I made some compromises. The 32u4 board I did has a lot of empty space. Could have easily placed a regulator and just choose to not populate if not needed. Once my prototype is tested I just might re-spin with that.

For this board, I ended up with plenty of free space as well. I decided to add a regulator, not thinking of the available IO. In retrospect it may have been more sensitive to dump the regulator in favor of an additional header for the additional available IO. Or could have tried squeezing a bit more. But there is also a time constraint, really needed to get this done, more so then the 32u4 which was just a learning exercise.

So all considered, it is built with my particular specifications in mind. Once I get the boards in my hands might re-spin them anyways. Need to iron out whatever bugs I discover. Also depends if there is any larger interest in the two designs I did. For the 32u4 it would most certainly make sense to add a regulator, there is just so much empty space on the board. For the 1284p I'd be more inclined to drop the regulator and add a header for I/O. We shall see....

Right now I am just tickled by how easy it is to get prototype boards made. I've been pretty absent from this stuff since 2005 or so. Last board I made was a PIC based ethernet board. DIP chips and mix of 0805 and through hole parts. A single sided PCB made at home using toner transfer. Was looking at commercial boards, but cost then was much more for a single prototype run then it is today. If I remember correctly, back then the best deal I found was in excess of $50 for 2 boards. This may have been a bare board without silk screen too. Maybe I didn't look hard enough back then, but I don't think BatchPCB, Seeed Studio or DorkbotPDX were around those days. Anyways,  I have been pretty anxious to get a couple of interesting boards whipped up and getting them made. Now I need to wait for the mail man. :)

*man... How many times do I have to edit my post to fix the iPad typos? The auto correct of the iPad is as much of a curse as it is a blessing...


Cool...  I want one  :smiley-mr-green:  

Hey but can you break out the rest of the pins??  You could make a 2-wide header that goes along an edge, kind of like Maple.

What is the big pad around U1 for?  A heat sink?  


Yes, played with a heat sink. My first time relying on board copper for heat sink. Used TO-220 and heavy duty metal in the past. So this board is a bit of an experiment to try a few things, and to keep a couple of projects moving that need more RAM then the 328 has to offer.

Will be playing with the board some more based on the outcome of the prototype and any suggestions and ideas I receive here.

I committed this one to being made. I'll be getting 10 boards in the mail. I only need 2. If the first build doesn't go up in smoke there'll be a few bare boards I am gladly willing to pass along.

CrossRoads

I've been using iteadstudio and buying 10, 20, 50 boards.
5cm x 5cm, $9.90
10cm x 10cm, $24.90
Shipping to east coast US  has been $5, about 3 weeks.
There pics at my signature link. Very good quality boards.

Keep seeing these guys in elektor magazine:

http://www.apcircuits.com/
might be worth looking into if in a hurry

I tried a quote, thinking of the '32U4 design that is kicking around elsewhere:
Two 1.5 x 0.75" boards, $19.60

"Basic Service: No soldermasks, no legends. Will ship the next business day."

Plus shipping:

"FEDEX is our EXCLUSIVE carrier. There is a minimum charge of $25.00 that covers most Prototype orders."

So that's a drawback!
Minimum sizes are also bigger that what iteadstudio will support:
trace width, trace spacing, hole sizes.
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.


I've been using iteadstudio and buying 10, 20, 50 boards.
5cm x 5cm, $9.90
10cm x 10cm, $24.90
Shipping to east coast US  has been $5, about 3 weeks.
There pics at my signature link. Very good quality boards.


I ordered from Seeed Studios or FusionPCB. Did not know of iteadstudio. Looks like both have the same cost for boards, but shipping to Canada is $5 with iteadstudio and I paid $8. Not a dramatic difference, huge difference compared to BatchPCB or any other North American offer I have come across.


My primary objective for the 1284P is to get the additional RAM (and code space). Also needed to maintain the traditional Arduino dimensions and header locations, including ICSP. There is more then enough IO on an ATmega328 for my purposes.
...
So all considered, it is built with my particular specifications in mind.


It looks good, different from Bob's (Crossroad's) Bobuino and also my Calunium, so between us there are a range of options for using the ATmega1284. I hope that somehow we can all collaborate to get the Arduino software fixed so that the SD and other libraries don't make assumptions over pin mapping but use the proper pin-mapping mechanisms implemented in v1.0.

How did you estimate the area needed for the PCB heatsink?


How did you estimate the area needed for the PCB heatsink?


Very unsophisticated.... just used the available space to maximum practical extend.

CrossRoads

Apcircuits: 80mm x 100mm - $73.

I think www.internationalcircuits.com will do 10 inch x 10 inch protoboards for $105 or similar.
Site says 10% discount for online orders too. skyjumper has been using them, they did yellow board at my signature link.
Got another board to post there also when I get home.

Regarding this:
"use the proper pin-mapping mechanisms implemented in v1.0"
I haven't looked at whats implemented for 324/644/1284, but I do know I disagree with pin mappings used for 32U4/Leonardo, compatibility with older shields disregarded and didn't need to be. Seems to be easier with the Variants folder now to implement a different mapping, need to look into that more.

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.

Quote
Seems to be easier with the Variants folder now to implement a different mapping, need to look into that more.


I will have to figure that one out. It seems one can define everything there is to a custom board and place it in the sketches folder. No need to modify any of the original Arduino distributed file. I sure hope that is how it works.


I've been using iteadstudio and buying 10, 20, 50 boards.
5cm x 5cm, $9.90
10cm x 10cm, $24.90


I second Iteadstudio. I've used them twice now and been happy on both occasions. To maximise yield I used more conservative design rules than the 8/8 mil they recommend. Rounded corners and cut-outs are supported.


Quote
Seems to be easier with the Variants folder now to implement a different mapping, need to look into that more.


I will have to figure that one out. It seems one can define everything there is to a custom board and place it in the sketches folder. No need to modify any of the original Arduino distributed file. I sure hope that is how it works.


That's the theory. In practice some libraries make assumptions about the pin mapping based on microcontroller type. The SD library has its own pin mapping tables, for the ATmega1284 it assumes the Sanguino pin mapping. :( I've forked the Arduino software on Github to get the my mapping used for the SD library. I've tried to replace this mapping table by the Variants one, but haven't yet succeeded. It seems that the pin mapping tables in Variants are only included when compiling the sketch.ino file, and not when associated libraries are compiled (see the #ifdef ARDUINO_MAIN compiler conditional in the standard pins_arduino.h files).

CrossRoads

"The SD library has its own pin mapping tables, for the ATmega1284 it assumes the Sanguino pin mapping. "
So as long as you keep SS, MOSI, MISO,SCK as D10, 11,12,13, there is no problem.
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.

CrossRoads

#462
Dec 31, 2011, 01:39 am Last Edit: Dec 31, 2011, 01:46 am by CrossRoads Reason: 1
Here's the 1284DIP layout I worked 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.


Here's the 1284DIP layout I worked up.


I think a lot of people like DIP. At least I noticed that there is a lot of asking for DIP versions whenever there's an interesting chip only in SMD. Personally I prefer SMD for anything with more then  28 pins. The DIP-40 seems a bit unwieldy. But that is just me....


Here's the 1284DIP layout I worked up.


This is quite nice!  What do you suppose the BOM cost is on this layout?   $) $) $)

I was wondering about the DIP, too.  Curious why you put the MCU in as a DIP when everything else is SMD?

What is the X3 header for?

Are those totally independent LED's for application use on 22 & 23?  If so, that's awesome.

(Sorry for the rainbow, my son is 'helping' me with this post...)

Go Up