My trial on Arduino layout http://sites.google.com/site/funlw65/electronics/jaluino-pinguino-28-pins-starting-bo/freejalduino
On Jul 26, 12:43 pm, Sebastien Lelong <[email protected]> wrote: > Hi, > > Here's a new schematic for Jaluino Medium board:18F4550 is replaced by > smaller 18F2550, so the PCB layout is expected to be easier, helping focus > on schematic rather than layout issues. I've recently received a couple of > them, so I'll be able to prototype few things. > > I tried to include Albert's suggestions, hoping it's correct now... Power > supply can be from USB or external, selected using a jumper. > > Any comments ? > > Cheers, > Seb > > 2009/7/26 Sebastien Lelong <[email protected]> > > > > > Hi Albert, > > > And many thanks for this ! For now, I think I'll go with solution B, which > > is the one I understand the most... > > > Seb > > > 2009/7/25 a.faber <[email protected]> > > > Hi Seb, > >> Attached 4 possible solutions > > >> Solution A: Almost the current solution, except added a bypass diode > >> across > >> the 7805, so it won't blow up if there is USB 5V and not external 9v > >> Solution B: Current solution, except make power selection via a jumper > >> selection (less user friendly, no voltage drop) > >> Solution C: Auto power selection via 2 schottky diodes (drawback, voltage > >> drop of ~0.3v) > >> Soltionn D: Auto power selection with self power dominance (drawback, > >> voltage drop of ~0.3v) > > >> General remarks: > >> D6, D7, D10, D11 in my schematic does not have to be a schottky type if > >> the > >> external supply is > ~8V > >> L1,L2,L3,L4 (ferrite bead, or power choke), not realy required, but > >> recommended > > >> Albert > > >> ----- Original Message ----- > >> From: "Sebastien Lelong" <[email protected]> > >> To: <[email protected]> > >> Sent: Saturday, July 25, 2009 12:42 PM > >> Subject: [jallib] Re: jaluino (first schematic... Richard ?) > > >> Hi Albert, > > >> I tried to do some research, but I'm lost, this is far beyond my > >> understanding and I can't figure out how to deal with self-power USB... I > >> need your help, would you mind giving me an example of self-powered USB > >> vs. > >> not self-power USB ? Your 18F14K50 PIC is self-power isn't ? I can't see > >> the > >> difference with my schematic... > > >> Also, I've found something about using a shottky diode to select +5V from > >> regulator or +5V from USB (see picture, part of schematic from an Arduino > >> board). Is that what you were talking about ? > > >> Cheers, > >> Seb > > >> 2009/7/23 [email protected] <[email protected]> > > >> > Hi Seb, > >> > Some comments on the schematic: > > >> > In the current schematic the 5V and USB-5V are connected, this is not > >> > according to spec, > >> > see also the datasheet about USB self-powering. Either way, use a > >> > jumper selection for the > >> > power supply or use some shottky diodes, in addition it might be wise > >> > to place a by-pass diode > >> > across the 7805, since these devices don't like to be reversed > >> > powered. > > >> > Why R1? I think you can remove it, since the reset pin is held high > >> > via R5/D2 > > >> > Be sure to put a 100n bypass close to VSS/VDD pins of the PIC, I don't > >> > know if C2 is the PIC bypass cap, if so I would > >> > draw it closely to the PIC VSS/VDD pins > > >> > BTW, the 18f14k50 board is working fine > > >> > Albert > > >> > On Jul 22, 9:37 pm, Sebastien Lelong <[email protected]> > >> > wrote: > >> > > Some more thoughts about Jaluino (next guy who talk about math lib, > >> can > >> > you > >> > > modify the subject plz ?)... > > >> > > The connector's layout is very important, as all shields will have to > >> be > >> > > compatible, and will reproduce this layout. > >> > > For instance, Arduino diecimila has 4 connectors: > > >> > > - 2 on on this upper side > >> > > - 2 on the bottom side, 1 being reserved to power > > >> > > Arduino mega uses a much bigger AVR than Diecimila. They put a double > >> > > row > >> > > connector, on the right side. Still, the four previous connectors are > >> on > >> > the > >> > > same place. As a consequence, shield for Diecimila can be used with > >> > > Mega. > > >> > > I'd like to reproduce the same. If we build first Jaluino board, > >> > > 18F2550, > >> > it > >> > > could have the same connectors as in Arduino (2 on upper side, 2 on > >> > bottom > >> > > side). Next step is a 18F4550 based board. We could add a single row > >> > > connector on the right. In the future, if we decide an even bigger > >> PIC, > >> > > we'll be able to double this left connector. > > >> > > That said, I still can't produce a PCB, I'm having a lot of trouble > >> > placing > >> > > parts to avoid vias... Any PCB guru here ? > > >> > > PS: as a bonus (...) here's my last schematic, with connectors. > > >> > > Cheers, > >> > > Seb > > >> > > 2009/7/21 Sebastien Lelong <[email protected]> > > >> > > > First try to get a PCB layout gives way too much vias. This is where > >> I > >> > > > spend days to get a decent PCB... > > >> > > > Seb > > >> > > > 2009/7/21 funlw65 <[email protected]>: > > >> > > > > On Jul 21, 7:49 pm, Sebastien Lelong <[email protected]> > >> > > > > wrote: > >> > > > >> I think this assumes the peripheral on the other side (eg. a PC) > >> > > > understands > >> > > > >> RS232 level between 0 and 5V, instead of -12V and +12V. It's > >> > sometime > >> > > > the > >> > > > >> case, and to be sure, using a MAX232 chip is better. That said, > >> > > > >> with > >> > the > >> > > > >> "plug your own serial module" option, you can choose whatever you > >> > want. > >> > > > This > >> > > > >> gives a fourth option, a the cheap side, so we new have: > > >> > > > >> - FTDI chip based USB-to-serial adaptor > >> > > > >> - 18F14K50 based USB-to-serial adaptor > >> > > > >> - MAX232 based, with DB9 connector > >> > > > >> - resistor based, with DB9 connector > >> > > > >> - (and last option: "my own way to deal with serial") > > >> > > > > Ok, not on board, but I thought they can be disabled by jumpers, > >> and > >> > > > > can be a fast solution to test the software but yes, is not a good > >> > > > > ideea. > > >> > > > >> Some more thoughts about the board. Original Arduino Diecimila > >> uses > >> > a > >> > > > >> Atmega168, a 28-pins chip. > >> > > > >> See:http://arduino.cc/en/Main/ArduinoBoardDiecimila. From this, > >> 20 > >> > pins > >> > > > >> are "exported" through connectors on sides, where 2 pin are > >> > dedicated to > >> > > > >> RX/TX, thus involved in board's functionality (I mean there > >> aren't > >> > > > >> completely free, as they are involved in serial). > > >> > > > > I don't know, maybe others have more ideas. First, I looked at > >> > > > > ATmega168 pins, to see some similarities at ports level but I > >> think > >> > > > > the key is at software level. And is the only level where Pinguino > >> > > > > offers Arduino compatibility (and maybe the reason why the author > >> > > > > didn't offered a shielded variant). > >> > > > > For "reusing" Arduino shields, I think a study must be done. > >> > > > > Studying > >> > > > > different shields with their software to see how interact with the > >> > > > > board. In what manner are used digital pins, etc. ... Because I > >> > > > > don't > >> > > > > think they take in account very much the particularities of the > >> chip > >> > > > > himself (I think the software is hiding the hardware). > >> > > > > Maybe is too much work but a shielded board is a must, even if not > >> > > > > Arduino compatible. This is jallib team decision, and I hope a > >> good > >> > > > > board will increase the number of programmers using jal language > >> > > > > (unfortunately, the fact that jal don't have a math library is > >> > another > >> > > > > obstacle regarding to "mass" adoption - the new comers remain > >> with > >> > > > > basic languages and advanced people go to C language). > > >> > > > -- > >> > > > Sbastien Lelong > >> > > >http://www.sirloon.net > >> > > >http://sirbot.org > > >> > > -- > >> > > Sbastien Lelonghttp://www.sirloon.nethttp://sirbot.org > > >> > > jaluino_sch2.png > >> > > 56KViewDownload- Hide quoted text - > > >> > > - Show quoted text - > > >> -- > >> Sbastien Lelong > >>http://www.sirloon.net > >>http://sirbot.org > > > -- > > Sébastien Lelong > > >http://www.sirloon.net > >http://sirbot.org > > -- > Sébastien Lelonghttp://www.sirloon.nethttp://sirbot.org > > jaluino_sch3.png > 51KViewDownload --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jallib" group. 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