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Topic: ATMEL Mega1284P evaluation board avalible (Read 180281 times) previous topic - next topic

retrolefty


I've been quietly assuming there would be some sort of announcement, asking for interest and/or orders before CrossRoads places his order for boards...


And I assume some time will have to be made to identify/develop the arduino support software files and instructions to make it all work together. I wonder how many of the contributed commonly used libraries will work without requireing modification?

Lefty


CrossRoads

After much careful lining up, and punch holes in paper, and getting parts to sit flat, and finding camera batteries, I managed to bump everything and take this blurry picture of the FCI SD socket and battery holder on the card (battery holder goes on the backside) next to a duemilanove for comparison.

I want to add some holes next to the Dxx shields to accomodate an RF Rx or Tx module or maybe a transceiver as an optional part that can be accomoted.
I have a set on my desk somewhere, just need to make sure they are lined up so the component sides are facing out & not interfere with the header connectors.


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.

mmcp42

looking good
always wise to check that real components match the layout you think works!
there are only 10 types of people
them that understands binary
and them that doesn't

skyjumper

That looks really nice. What did you print the gerber out on? Or is it not a gerber? It looks like an actual PCB...

mowcius

That mounting hole is much too close to the SD socket and the one below that looks rather too close to the headers too.

CrossRoads

The printout is 1:1 from my eagle color laserjet, CP1215 model. Can be found on sale fairly frequently for $150. Gave up on inkjets and cartridges drying up/becoming unusable with my infrequent printing.

Mounting holes - thought I had enough space - putting actual #4-40 screwhead and nuts on top of the holes does show it to be pretty tight!
Will have to spread things out a little now. Thanks Mowcius.
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

Cool, what generated the image? Gerbers tend to be black and white. Did Eagle make the image?

CrossRoads

Yes, it is just the eagle output of the top layer.
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

Alright, did a bunch of rerouting and made the board a scooch bigger, 3.95" x 2.4" (100.33 x 60.96mm)
This gives the mounting  holes more room, will do another print tomorrow & confirm screw head/nut clearance.
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

Hi Gang,
Can I get a last review of the layout before I proceed to place an order for 11 CCAs with International Circuits and material with Digikey, etc.
I have been going over this with Skymaster learning from things he's found, and also incorporated I believe all the prior comments I've had here.
Files are located here:
http://www.crossroadsfencing.com/atmega1284_Rev13_Radio.sch
http://www.crossroadsfencing.com/atmega1284_Rev13_Radio.brd
http://www.crossroadsfencing.com/Rev13_parts_list.xls

(right-click, Save Target As, rename with correct extensions)

I've just started the PL, I have digikey PNs in another file, need to merge the two.

Features: Compatible with regular shields
SPI to SD socket with non-shield SS line, 74AC125 level translater
Jumper to connect I2C or A4/D18 - A5/D19 to the shield (or, can connect both with proper software)
I2C lines have 10K pullup
RTC with battery backup (battery holder goes on bottom of the card), 32.768KHz crystal
RTC Square wave out goes to jumper field to drive INT2 or PD7 (both non-shield lines)
Mounting holes are on 0.1" spacing
Mini-USB-B connector
5.5/2.1mm power jack
ATMega 326/644/1284 will plug in,16 MHz crystal
Surface mount or thru-hole 5V regulator (to allow easier heatsinking if it should run hot or to move offboard)
Dual serial - RX/TX connects to D0/D1 and USB. RX1/TX1 connects to D2/D3,  with jumper field to allow connection to RS232 driver and pins to connect to offboard DB9 connector.
Jumper to allow disconnecting of Reset capacitor
Jumper to allow 5V from USB or from Regulators.
3.3V on shield from FTDI USB ship.
3.3V regulator to power SD.
Will accept MicroSD socket or Full size FCI SD Socket
8 pin header for PC0-7, 4 of which are also JTAG signals, and 2 of which are I2C
ICSP pins
JTAG pins
Holes for mounting 315/434 MHz RF RX or TX module (one or the other), data from D9 pin. I guess I could find a way to connect that to a non-shield pin like PC6 or PC7, the only pins totally undedicated. Laipac RLP434 & TLP434 for example, same type as sparkfun used to carry from Holy Stone.

Any questions, comments, I think I am about ready to place an order & go do some surface mount soldering with Skyjumper!
Ooh, need to get a stencil created too ...

Thanks!
Robert/Crossroads
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

Oh, I'll send you some info on the stencil. The Oharp (spelling?) stencil was fine, just be sure to warn him that the round pads are not holes and they need to stay. The only IC that might be an issue is the USB FTDI chip. It will help to touch up the gerber file to make the opening for those pads narrower. Other than that, I think its a very easy board to stencil and place.

pito

#236
Jun 23, 2011, 02:16 pm Last Edit: Jun 23, 2011, 02:29 pm by pito Reason: 1
@Crossroads: If I were you I would place the large sd socket on the top and the micro sd socket on the bottom layer of the pcb. Maybe 20mins of a hard work ->> and you may use both (mind additional /cs) in parallel..
]:) Pito

PS: Why you do isolate the "cooling polygons" beneath the both voltage reglers from the surrounding GND? You are loosing maybe 70% of cooling efficiency there then..

skyjumper

If he puts SMT components on both the top and the bottom, that will make the board much more difficult to reflow in a toaster oven.

pito

#238
Jun 23, 2011, 10:21 pm Last Edit: Jun 23, 2011, 10:22 pm by pito Reason: 1
.. the soldering the microsd on the bottom side is not a big deal, the added value of having there both sdcards is much bigger, though. BTW, he can leave the both sd card traces on the top as they are now, _and_ to add the new one for one microsd on the bottom. So everyone may do it manually afterwards, when required. Remember an additional card_select signal from somewhere then..P.

CrossRoads

The 5V regulator needs to be isolated, the pad is 5V while the ground polygon is .. ground.
The other regulator takes 5V down to 3.3V and I  don't think actually gets hot.

Putting microSd on the bottom -  I was thinking reflow as skyjumper said, and only having one or the other in use.
I don't see any reason it couldn't go on the bottom, will have to see what the part looks like mechanically & ease of hand soldering.  Good suggestion pito.
I was thinking most folks would opt for the microSD from the # of earlier comments against the SD, but that was the socket I wanted to use so cards could go right into a PC with no need for an adapter (just more pieces to lose!).
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.

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