2011/2/5 vasile surducan <[email protected]> > Also, on my first tries, there were many many vias, and I tried to have as >> few as possible. Going that small will mean more vias. Is this a problem ? >> For instance, PIC's datasheet says caps near xtal should on the same side. I >> tried to respect this. >> > > of course but you can use as well a SMD crystal on the micro side or on the > opposite side as well >
Ye, I found smd crytal not so easy to find and quite expensive too. I found resonator too, but this may not be accurate enough in some cases. > > >> >> What about the fuse ? Do you think it's properly positioned ? Since there >> are many power source options, I can't put a fuse for each... >> > > well, I dislike your style of powering board (JP3 and JP7 both ON by > mistake could kill your USB) > I'm not happy too with this. I thought about this a lot, without good results as you can see. I could remove external source, thus removing JP7. > but that is, usually the fuse is protected by the micro or by the > regulator, however one smd fuse (thermal or breackable) is enough, but I'm > afraid yours will not protect something... > So where do you suggest to put it ? BTW symbol is resettable but I'm planning to use "real" smd fuse. Cheers, Seb 2011/2/5 vasile surducan <[email protected]> >> >> >>> >>> On Fri, Feb 4, 2011 at 8:59 AM, Sebastien Lelong < >>> [email protected]> wrote: >>> >>>> Hi guys, >>>> >>>> >>>> So...I'm back, after several tries. >>>> >>>> It was possible to keep most features, specifically providing 2 >>>> voltages, 5V and 3.3V. This was quite a mess though, mostly Xbee requires >>>> 3.3V, and possibly voltage shifter on inputs (datasheet says it's not 5V >>>> tolerant, but some report it is in reality). So I removed 5V regulation, >>>> and >>>> kept only 3.3V, making this board more 3.3V devices friendly. If Xbee isn't >>>> wanted, then one would just put an AMS1117-5V instead of 3.3V version. >>>> >>>> I worked again on power supply inputs. There can be 4 sources: USB (5V >>>> regulated to 3.3V), external (5-9V regulated to 3.3V), serial (no >>>> regulation >>>> so must output 3.3V, quite rare), and battery (direct, no regulation). I >>>> put >>>> a fuse after the regulation part. >>>> >>>> Since I had some room left, I added a microSD slot, though I still >>>> wonder how I'll solder it... :) It's on the bottom side. If replacing 3.3V >>>> regulator with a 5V one, again SD-card won't work. >>>> >>>> I doubled shield/breadboard connectors to allow breadboard + shields at >>>> the same time. User could also solder some wires to plug the board to >>>> external daughter, using external connectors/holes. Shields can also be on >>>> top or bottom, both, etc... >>>> >>>> I may also add another pin header which would include supplied voltage, >>>> making it available to shields/breadboard (voltage coming from USB, >>>> external, ...). >>>> >>>> Anyway here's the result, see attached files: schematic, PCB, PCB top, >>>> PCB bottom (some comments are wrong, sorry). >>>> >>>> >>>> Feedback appreciated. Highly ! >>>> >>> >>> Your designs looks better and better. However there is HUGE empty >>> space on your board. Look for example the footbal field between the crystal >>> and the micro. >>> When using SMD one of the reason is miniaturization. But your board is >>> still huge. >>> You cand do it with only 20% larger than the xbee itself? >>> >>> Vasile >>> >>> >>> >>>> >>>> >>>> Cheers, >>>> Seb >>>> >>>> >>>> 2011/1/30 vasile surducan <[email protected]> >>>> >>>>> >>>>> >>>>> On Sat, Jan 29, 2011 at 10:49 AM, funlw65(Vasi) <[email protected]>wrote: >>>>> >>>>>> I think you will need to design two boards. One supporting USB uCs and >>>>>> second for serial uCs. Keep 1206 smd components, otherwise you must >>>>>> provide the board assembled. And this is because of 5x5mm limit. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>>> Try >>>>>> to see how many features you can put on a single type of board. >>>>>> >>>>> >>>>> all you need... >>>>> >>>>>> >>>>>> Vasile >>>>>> >>>>>> >>>>>> On Jan 29, 6:03 am, Sebastien Lelong <[email protected]> >>>>>> wrote: >>>>>> > Hi guys, >>>>>> > >>>>>> > Here's my last version, including a 500mA fuse (not resettable, but >>>>>> I only >>>>>> > have this one in my eagle lib), a rectifier diode for reverse >>>>>> polarity >>>>>> > protection, onboard LED moved to RC2 (CCP1 pin). Some remaining >>>>>> "doubts": >>>>>> > >>>>>> > - which package would I need for the diode: DO-214AA, DO-214-AB or >>>>>> > DO-214AC ? >>>>>> > >>>>>> > - I still have doubts about the power supply part. Initially, I >>>>>> wanted to >>>>>> > have power through USB or a battery. The board should handle 3.3V >>>>>> and 5V, as >>>>>> > an option. When using a battery, say 2 x 1.5V AAA cells, I'd need to >>>>>> bypass >>>>>> > all regulation (maybe even a pump like this: >>>>>> http://www.sparkfun.com/products/9216). Using a rectifier diode will >>>>>> also >>>>>> > drop the voltage down and may not be compatible. But I could also >>>>>> use a 9V >>>>>> > battery, and thus need 5V and/or 3.3V regulators... and what if 3.3V >>>>>> is >>>>>> > bypassed, but not the 5V regulator ? Xbee board will be powered with >>>>>> 5V, >>>>>> > instead of 3.3V!!! You guessed it, I want many things and I'm not >>>>>> sure which >>>>>> > is most important at this phase. Any input, advices ? I think when >>>>>> I'll >>>>>> > start to create the PCB choices will be easier to make as I discard >>>>>> options >>>>>> > to gain room :) >>>>>> > >>>>>> > - I added pin headers, 2 x 14 pins, I may add another one >>>>>> dedicated to >>>>>> > power pins (like in Medium) if I get enough room (I doubt about it) >>>>>> > >>>>>> > In order to save some precious room, I'm thinking of (high priority >>>>>> to low): >>>>>> > >>>>>> > - removing Reset-via-RTS option and make it always available >>>>>> (2-way jumper >>>>>> > saved) >>>>>> > - remove two I²C jumpers, always make the board acting as a >>>>>> master, and if >>>>>> > not wanted, just don't solder the resistors >>>>>> > - remove CTS jumper option (not used often ?) >>>>>> > - remove power from serial module option, focusing on USB or >>>>>> battery >>>>>> > - keep only one regulator, adding an optional resistor to match >>>>>> required >>>>>> > 3.3V for Xbee when using 5V reg only. >>>>>> > - move to 0603 smd components..... >>>>>> > >>>>>> > Any feedback highly appreciated! >>>>>> > >>>>>> > TIA >>>>>> > Cheers, >>>>>> > Seb >>>>>> > >>>>>> > 2011/1/25 mattschinkel <[email protected]> >>>>>> > >>>>>> > > > Maybe I should just use two different voltage regulator, one >>>>>> AMS1117/5V >>>>>> > > and >>>>>> > > > AMS1117/3V3. Having only one component would have helped while >>>>>> sourcing >>>>>> > > > them. >>>>>> > >>>>>> > > On one prototype board I bought, there is only a AMS1117/3V3. They >>>>>> > > assume you want to input > 5v and get 3v output. If you want >>>>>> another >>>>>> > > voltage you can put a jumper (just solder) to connect the >>>>>> input/output >>>>>> > > of the regulator so your voltage is whatever the input is. >>>>>> > >>>>>> > > Matt. >>>>>> > >>>>>> > > -- >>>>>> > > 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]<jallib%[email protected]> >>>>>> <jallib%[email protected]<jallib%[email protected]> >>>>>> > >>>>>> > > . >>>>>> > > For more options, visit this group at >>>>>> > >http://groups.google.com/group/jallib?hl=en. >>>>>> > >>>>>> > >>>>>> > >>>>>> > jaluino_v03_bee_schematic.png >>>>>> > 62KViewDownload >>>>>> >>>>>> -- >> 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]<jallib%[email protected]> >> . >> >> For more options, visit this group at >> http://groups.google.com/group/jallib?hl=en. >> > > -- > 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]<jallib%[email protected]> > . > > For more options, visit this group at > http://groups.google.com/group/jallib?hl=en. > -- Sébastien Lelong http://www.sirloon.net http://sirbot.org -- 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.
