Hi Vasile, Thanks for your feedback too !
Are you saying it's possible to make such a board only 20% greater than Xbee ? I could try to redesign it, but the bottleneck will pin header connectors. 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. 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... 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]. 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