Hi Vasi, I have other arguments in favor of using an intermediate shield and not having pins compatible with Arduino shields directly to the board (for funlw65).
1. If you look at ATMega 168 pin layout, and look at an Arduino Duelmilanove, the shield connectors are directly aligned with ATMega pins. Just as Jaluino V1.0 has his shield connectors directly aligned with 18F4550 pins. This is why we have a simple PCB, which can be made homebrew. Atmel seems to be more organized than Microchip when dispatching pins by functions... For instance, ATMega has all its ADC pins in a row. As a consequence, there's one Arduino connector with all of them. On the other side, 18F4550 has its ADC pins dispatched everywhere, and sometime ADC pins aren't even numbered in continue of some other PIC. That's the way it is, Microchip puts a lot of mess :) Now if you Vasi want to have a pin compatible board, you'll have to face this inconsistencies. Of course, and obviously, it can be done, but then you spread AtMega design on top of Microchip's, you put constraints on your PCB whereas it can naturally follow pin diagrams. To have a software analogy, it makes me think of a leaky abstractions: you let ATMega pin layout interferes with 18F4550 (and another one would be, "if you have a problem, add a layer" as they say in software) Of course I agree being able to use Arduino shields would be great, and that's why I'll try to design this intermediate shield as soon as possible. I also understand you want your FreeJALduino board to be usable with Pinguino. In this case it makes sense since Pinguino is a clone of Arduino, it provides the same langage and ultimately you'll be able to take your FreeJALduino board, pick a shield, compile the code provided with the shield with Pinguino and voila ! you have a working stack, just like Arduino, using the same language, but PIC based (one would argue why not using an original Arduino...). 2. You clearly showed in your blog that you had design issues in cloning an Arduino board. For instance, you'd need more pins (missing two), not all have the same functions, as already said etc... In your last design (your link), you show a 18F4550 based board, always pin compatible with Arduino shield, but also having another connector. So you have one part being compatible with Arduino Duemilanove, and the other being compatible with... nothing (following your logic, I would have made it compatible with Arduino Mega, at least partially since Arduino Mega a lot more pins then 18F4550....). With this approach, you're in the middle: either you miss pins (18F2550), either you have too much and don't know what to do (18F4550) and not fully going in the way you want, that is, being compatible with Arduino. The approach with Jaluino is to fully exploit the chip, have a clean, "natural" layout, and if needed/wanted, use the intermediate shield and downgrade the board functionalities (some pins aren't used) to use Arduino Duelmilanove shields. Using an intermediate shield you can also abstract the chip,ie. the main board. Being 18F4550 or 182550, or 18Fwhatever, you'd just have to plug to correct intermediate shield to expose your bottom main board in a Arduino fashion way. Phew... well I hope you did understand what I mean :) Cheers, Seb -- Sébastien Lelong http://www.sirloon.net http://sirbot.org 2009/8/28 funlw65 <[email protected]> > > Hi Richard, > See here how i want to make my next board based on 4550: > > http://sites.google.com/site/funlw65/electronics/jaluino-pinguino-28-pins-starting-bo/freejalduino-mega?pli=1 > > It have a lot of bridges but is because of Arduino shield > compatibility. It can be made at home and also as a double-sided pro > board (through hole components). > > Is also designed to be programed with Pinguino (but Pinguino must be > adapted to it - is not hard to do). > > Of course, I'm not an expert. The design can be much better... > > Regards, > Vasi > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/jallib?hl=en -~----------~----~----~----~------~----~------~--~---
