New 1284P-powered board suggestions

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New 1284P-powered board suggestions

Postby andrew » Sat Dec 28, 2013 12:44 am

We're currently working on a new Arduino-compatible board that runs the Atmel ATmega1284P microcontroller (as used in the Goldilocks and would be interested in your feedback or suggestions.

For example, what do you want on the board? Do you just need the extra memory of the MCU and none of the other hardware features (e.g. SD card socket)? Does anyone even use the JTAG connector? Are you happy with an Uno-standard power supply? And so on.

Please reply with your thoughts, suggestions or requests and we'll work through them in the next few weeks to help develop the next board.

Thanks in advance from the Freetronics team.

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Re: New 1284P-powered board suggestions

Postby geoff76 » Sat Dec 28, 2013 1:15 am

Freetronics Team:

I would suggest what perhaps would be the 'easy' way - but quite elegant. Simply use the 1284P chip instead of the 328P and make the rest of the board as identical to an UNO/Duemilanove as you can. SD card slots, and other extras only add cost and heck, that is what shields are for!

If possible, I would like to see the DIP version of the MCU in a pullable socket (in case of 'frying' the chip) versus the tiny SMD style.

- geoff76
JGS_1976 on Twitter

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Re: New 1284P-powered board suggestions

Postby hiduino » Sat Dec 28, 2013 2:49 am

Yes, I would also agree that it should be as close to as possible to the Uno R3 pin outs and functions. So that it can be a drop in replacement with more RAM/Flash memory. What the current Goldilocks is mostly there, just the digital pin mapping should be adjusted more towards the Uno. (see my post,

All the extra features are nice but a lower cost board would be better as a drop in replacement for an Uno. Maybe you can have multiple versions. A cheaper Uno clone replacement and then a souped up version.

I like the idea of the high quality audio DAC. It's hard to get good audio from shields.

I think most hobbiest don't use JTAG, so that is mostly wasted space.

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Re: New 1284P-powered board suggestions

Postby rwmTinkyWinky » Sat Dec 28, 2013 3:02 am

Hi there, you may remember me from many years ago at the LCA Arduino miniconf giving a talk about XMEGA internals.

There were a few key decisions I made when I started a design for an XMEGA-based arduino clone. These are the things I look for in improved or changed features from the standard official boards.

#1 - Conflict-free additional hardware.

I really hate it when a board adds additional features but overloads the shield pins. Okay, the extra hardware is nice but if it takes away IO pins from the shields and there's no way to disable it, then it makes the shield IO a bit useless. It's already hard enough to sort out what pins shields use without half the IO pins taken oven by on-board hardware.

For some stuff, this is easy.. SPI devices just make the !CS pin not one of the shield IO pins and have it pulled up by default. LEDs other the D13's LED belong off the shield IO pins, same goes for rotary encoders sensors and whatnot. I2C have some straps you can cut if you want.

#2 - Use additional IOs if they are there

The additional flash and RAM of the newer MCUs is great, but given you've got the spare IOs you may as well use them. This folds into point 1.

#3 - Decide if it's a close cousin or a completely different board.

I really hate the Leonardo pin-out, and the fact SPI is now "officially" from the ICSP header rather than D10-13 where it was. I2C is sort of overloaded on A4/A5 because that's where it was on the 328P but there are now dedicated I2C shield headers. Okay, well, it's a bit of a mess, so either decide you're going to follow the Uno pin-out closely or not at all, and document what the variation is. (IMO, PWM is about the only thing which I think is okay to vary, otherwise please stick to common usage!)

#4 - The shared USART

A few times I've run into people who are surprised they can't have separation between the shield USART (where, for example, you'd whack GPS or GPRS shields) and the PC/console USART. 1284P has two of them, please split it so they're now no longer shared!

Okay, what about the JTAG port etc. I know most people don't use it, although it's very cheap to get something to debug with it (ie, the AVR Dragon). That said, if it was a choice between #1 and JTAG, I would choose #1 every time, and I don't get the impression many Arduino people do JTAG anyway.

On the power side, well I'm biased towards switchmode. I put together a switchmode input shield ( ... r-arduino/) kit precisely because I think either you're better off with a variety of beefy 5V sources (in which case, just lose the 5V reg entirely), or do it properly for wide input.

Anyway, that's my rant. YMMV. Shall be interested to see a 1284P variant, I had considered for a long time building one myself after the chip became available but.. hobby vs job. :)

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Re: New 1284P-powered board suggestions

Postby stryker » Sat Dec 28, 2013 4:36 am

Hi guys

Lots of good suggestions here. If you're tending toward a Uno with a bigger brain then please do continue development on Goldilocks as an independent product. I love the concept of Goldilocks, and with the exception of a couple of items I think it's pretty darned close to being the porridge that's just right that Phil set out to build. Goldilocks is seriously so much more useful than Mega in my view.

For mine if 'Goldilocks 2.0' fixed those final niggles, including the uSD slot using a shield pin, and if the jumpers on board were easier to change back and forth for different prototyping projects (ie not solder bridges, but DIP switches or old-school jumpers) and if there was a protoshield that picked up the extra IO pins that would be juuuust right.

Back to the subject at hand: I probably wouldn't buy a Uno with a big brain, but I'm not the best judge. I didn't see the genius of LeoStick until I had my first either.

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Re: New 1284P-powered board suggestions

Postby europa » Sat Dec 28, 2013 4:46 am

Hi Guys,

Sorry to hear of the demise of the "Goldilocks" board, can appreciate the amount of effort
Phillip Steven's put into this baby, as I cobbled together a much more basic 1284P board, a couple of years back. Anyway, here's my two bob's worth!

Essentially, keep it simple:

(i) use the standard Arduino footprint, " as much as possible ". It can be done as exampled by the Calunium and Elouera 1284P board iterations.

(ii) loose the ATmega32u2 co-processor, or any other co-processor.

(iii) use the 40 pin DIP flavour, if you fry the chip, just pull it out of the socket and replace it with a new one.

(iv) incorporate a coin cell battery-backed real time clock chip eg. DS3231N

Guess, what I would really like to see is a vanilla Kit Ten, with a DIP 1284P and decent battery-backed RTC (DS3231N not a DS1307).

Couldn't resist, thought I might just attach a couple of photos of the boards I cobbled together. Essentially, a Freetronics Kit Ten clone but using a 1284P.

fig(i) Kit Ten clone and 1284P using Kit Ten as template single-sided through-hole pcb.
fig(ii) 1284P single-sided through-hole pcb.
fig(iii) 1284P double-sided through-hole pcb.

fig (iii).JPG
fig (iii)
fig (ii).jpg
fig (ii)
fig (i).jpg
fig (i)
Last edited by europa on Sun Dec 29, 2013 12:15 am, edited 3 times in total.

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Re: New 1284P-powered board suggestions

Postby feilipu » Sat Dec 28, 2013 6:26 am

It is great that Freetronics is continuing with the "Goldilocks" 1284p boards.

I know that Jon and the team have been working on a few new 1284p prototype designs since the our first iteration in May (like the Arduphone at Linux Conf 2014), so this is a chance for everyone to comment on what they'd like to see on the next iteration of Goldilocks.

My 2c.
  • keep the current Goldilocks hardware pin-out as it best matches the Arduino R3 features. Consider the software pins_arduino.h pin mapping separately.
  • fix the uSD SPI Chip Select errata, to get this function off the shield pins.
  • fix the JTAG VREF errata (or delete JTAG and re-assign IO pins).
  • use FTDI FT232R for USART (head -> desk).
  • keep high current power supply (I've done a re-layout that might help to reduce digital noise).
  • add a switch to disable the DTR Reset. I would like a reversible way of having a running device NOT to be reset by plugging the USB cable.
  • keep full size, through hole, crystal, so alternative MCU clock rates are possible.
  • keep the 32kHz watch crystal, because avr-libc will soon include standard C time functions (ISO/IEC 9899 C90), so "real" Arduino time based functions are not far away. Non-stop real-time battery operation is also possible.
Also, I think it would be great to develop a low profile "inner" or "mezzanine" proto-board that picks up all 3x 8bit aligned IO Ports on their through hole pin-outs, but doesn't block the R3 pins. This mezzanine proto-board could be mounted between a standard Arduino R3 Shield and the Goldilocks 1284p, or be mounted under the Goldilocks like a baby-bump. This could allow extended simple prototyping between a Shield and the Goldilocks, or larger prototyping projects to be built using all of the 1284p IO, without impacting Arduino R3 Shield usage.

I'm playing around with another iteration Goldilocks Analogue too, that adds in high quality dual channel DAC capability (derived from the Adafruit wave shield). But, because of the cost of Op Amps OPA4132, and DAC components it is unlikely that this Goldilocks derivative would get wide application, except perhaps for analogue control systems, synthetic sound devices or controllers, or other fringe uses.

By the way, it hasn't been discovered yet, but the very tasty Gamduino 2 is perfect for paring with a new Goldilocks 1284p. The Gameduino 2 doesn't implement the R3 pinout, and only has SPI on the traditional Uno pins. But, you will need a lot of RAM to build a great video game which means Goldilocks in - Mega out. My Gameduino 2 has been delivered... mwahaahaa!

Good luck.
Last edited by feilipu on Thu Jan 30, 2014 1:28 pm, edited 4 times in total.

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Re: New 1284P-powered board suggestions

Postby Brian » Sun Dec 29, 2013 7:35 am

This sounds like a great idea. :)

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Re: New 1284P-powered board suggestions

Postby jebz » Sun Jan 05, 2014 9:11 pm

1284p board features -
Definitely keep the switch mode power supply. Add ethernet similar to the Etherten as ethernet projects could use more memory. The ATmega32u2 could go. Programming via the ICSP is fine or add pins for FTDI USB. Keep the SD card but seperate it's MCU pin use from the shield pins. Keep the second serial port.

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Re: New 1284P-powered board suggestions

Postby lmimkac » Mon Jan 06, 2014 9:14 pm

By now just having studied the current Goldilocks design, I have to agree on the post from feilipu above as I would bring these to your attention anyway.

I would add the following:

1. Fix the uSD SPI Chip Select errata, to get this function off the shield pins. I would just add a jumper to either route the pin to the Arduino shiled pins, or to the non-Arduino ones.
2. Add and I2C RTC circuitry with a battery holder (could be on the bottom of the board and connected to the I2C Bus; None of these does actually need to be soldered, they can be added later on by those who wish to have the functionality embedded). You can actually sell the kit standalone.
3. Keep the JTAG header, but also distribute the pins to the 2nd Non-Arduino shield pins
4. Bring up a proto-board alongside the “New Goldilocks” that would fit the Arduino and Non-Arduino Pins. It could actually be re-sized by cutting the Arduino specific part (Arduino Shield pins)
5. Keep the size as it is. The few millimetres more does not bring any damage, the LEDs visibility is great and useful added feature, however, not so important
6. I suggested earlier that you could add some accelerometer to the board too….
7. Otherwise, the design looks almost perfect to me. I think feilipu did a great job, or whoever in the end designed/finalized it it. Apart from the the miniSD CS... ;-)

I believe that the board will mostly be used by those who know something about electronics already. But you know this better than me…

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