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Topic: ATMEL Mega1284P evaluation board avalible (Read 179395 times) previous topic - next topic

mowcius

Hmm - I'd opt for a neat 45deg angle and a 1mm longer track any day but maybe that's just me

mmcp42

there are only 10 types of people
them that understands binary
and them that doesn't

mowcius

Quote
^^^ wot he sed ^^^

I'd also opt for a few ms longer typing time and correct spelling and grammar any day :D

mmcp42

there are only 10 types of people
them that understands binary
and them that doesn't

48X24X48X

#109
May 22, 2011, 01:50 pm Last Edit: May 22, 2011, 01:59 pm by 48X24X48X Reason: 1
While waiting for other boards to return from the fab, I give the ATMega1284P board a go. And here's the outcome!




I wanted the board to have minimal components and made the board as simple as possible. Some descriptions of the board:

  • Uses 6-pin FTDI cable

  • 5V/3.3V operating voltage selection through jumper

  • Optional 32.768 kHz

  • I2C pins location selectable to be either on analog pin row or on PORTC breakout header

  • Pin 13 LED driven through a MOSFET

  • Some small prototyping area

  • Same mounting holes position as Uno

  • Same ISP header location as Uno

  • JTAG header



I have thoughts of using a smaller output current 3.3V regulator but with very small quiescent current. This will allow for lower power usage and maybe use the 32.768 kHz in asynchronous mode during sleep. In this case, input voltage (battery maybe) is stuffed in from the 5V instead of the DC in. Comments and critics are welcome. No plans for fabrication on this board yet. :)

CrossRoads

Nice expansion from a 328 to the 644/1284 family.
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.

graynomad

Nice-looking layout, not auto-routed I'm guessing.

I can't read the schematic, are you using an inductor on AVCC?

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

48X24X48X

Rob,

I think you can view the schematic on the image source link (Flickr) itself. Not too sure why the image was resized.
It's manually routed totally. And yes, there's an inductor on the AVCC. :)

pito

..my strong feeling is the board needs an external RTC.. the idea running 1284p with the optional 32khz xtal @timer2 is nice, but when you start to work with it you will be soon unhappy not having the actual time ready anytime.. maybe to trade it for jtag and the prototyping area.. with a small dia coin cell it may fit, maybe..

mowcius

Manual routing is the way to go - see how neat it looks all with nice 45deg angles :D

CrossRoads

I'm doing the other one manually now, got about 10 signals to go. The ones that go from the top of the board down to the middle & bottom are a pain.
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.

mowcius

Quote
I'm doing the other one manually now

Heh, nice :)

You'll never go back to that evil autorouter!

CrossRoads

Okay, after much time  manually routing and tweaking signals to maximize ground plane coverage, here's what I have.
Am still looking into which SD card socket to use so that corner may change a little, or I may  just leave alone for the sparkfun offering.

We're noticing that the Duemilanove and the Uno changed pad shapes from round 0805 pads to square pads for some components (along with going to what looks like mere specks of sand for some parts o) ) - anyone know the reason for change on reasonalbe size parts?


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.

bubulindo

This... is a hobby.

48X24X48X


..my strong feeling is the board needs an external RTC.. the idea running 1284p with the optional 32khz xtal @timer2 is nice, but when you start to work with it you will be soon unhappy not having the actual time ready anytime.. maybe to trade it for jtag and the prototyping area.. with a small dia coin cell it may fit, maybe..


I manage to add PFC8563T RTC with a 12mm coin cell. I guess it will last you for a long time. And there's some library around for that chip. As there's a 5V & 3.3V selection, the RTC needed to be able to operate on both voltage and PFC8563T fits that and didn't burn a hole in the pocket.
I'll stop here for the board! If any of you guys are interested, I'll post the CAD files probably on GitHub.



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