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1  Products / Arduino Due / Re: Arduino Due Mini/Nano on: October 29, 2012, 06:54:54 am
I guess that since Masssimo Banzi did not mention the topic of if there was a Due Mini/Nano officially in the works at the present time, then there probalby is not.

I had seen the Teensy 3.0 already at the time I first made this post, and that was why I naturally asked if there were any plans for an "Official" Arduino version with mor guaranteed  future Software and hardware support.

As far as the Due Mega+  (Giga?) size factor goes, I will probalby only ever buy one for prototyping and so on. A Due Mini on the other hand more like 3+ for all those flying, walking, roling, swiming things where size/weight is definetely an issue. Never mind all the wearable and hideable stuff.

To CrossRoads:
Quote
Start writing up some requiremets, I'm sure it can be reduced to a smaller size.

- desired size
- desired power sourcing
- desired pinouts
- desired headers
- desired built-in interfacing
- etc.

Size: Same as the mini, Perhaps 4 to 8 Pins longer. Just as wide with perhaps a second parallel auter row of pins. I would prefer a rectangular board over a square one. More perimeter to surface area.
Headers: Suggestion: Male headers down for breadboard compatibility, Female headers up for additional pins.
Power sourcing/Interface: USB, Battery 5 to 15V, FTDI would be OK too.
Pinouts: 1.5 to double the amount of the pins on the Mini.

As to which pins... thats where the fun begins. Suggestions? I don't think there will be a please all solution here with all the available capabilities.

J

2  Products / Arduino Due / Arduino Due Mini/Nano on: October 23, 2012, 01:32:43 pm
This may be a little premature, but does anyone know if an Arduino Due Mini/Nano Teensy sized board is planned?
3  Development / Other Software Development / Interupt Driven Simultaneous Servo Library (max seros:8 max refresh: 333Hz) on: March 04, 2012, 04:34:23 am
After using many Arduino libraries, I figured it was time to return the favor and contribute one myself. Perhaps someone can use it.  I didn't find anything like it anywhere else for controlling many digital capable servos simultaneously at high refresh rates.

Interupt driven to free up resources (as opposed to the softwareservo library). High refresh rates reduce input lag times in unstable systems (Quad, FBL heli, Segway etc.). Theoreticaly synchronization reduces "wobble" where synchronization is critical. e.g.3 servo heli swashplates.

The maximum safe servo refresh rate of the original servo.h library is the max number of servos * the max PPM width eg. 2500us plus a little overhead.

I took the Arduno interupt driven servo library and the Software servo library and made a hybrid simultaneous interupt driven servo library out of them. Result, a digital servo/esc capable simultaneous servo library. At the moment only one port (B,C or D) can be chosen at once. 8 Servos (PortB 6) simultaneously up to 333Hz is possible.  I only use it at the moment at 200Hz though.

Theory: Sorts all the PPMs in ascending order, shift the non simultaneous and following ones by 25micro seconds, which is a bit more than the minimum needed so that the interupts don't get in the way of each other and mess up the PPM/PWM widths. Uses Timer 1.

I've only tested it on a Arduino pro-mini 16MHz and the Uno, so it is very Atmega 328 specific because of the Port calls. Its still a work in progress, but it does the job very well at the moment in my balancing robot project. The only problem to date seems to be that the interupts don't work very well with simultaneous Serial transmisions. This is no big problem for me, because at my 200Hz cycle time I can send my Serial info after the servo has fired but before the next cycle between the 3ms and 5ms time. I've synchronized my main program loop to the servo routine timer counter.

Long story short. I'm new here. Where and how is the best way to post my library other than attaching it here (shows up only if you are logged in I think) and any hints as to why the above problem occurs?
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