One more: if you are routing paired signals (like USB D+ and D- ) try to keep at least the same impedance for both of them (meaning atleast the same lenght and traces routed as one pair). USB has a specific impedance for D+/D- (even USB1.1).
Vasile On Sat, Oct 30, 2010 at 7:33 AM, funlw65(Vasi) <[email protected]> wrote: > Hi, > > As many others I'm scared by the smd so only 1206 size components > used. Those through hole components helped a little in routing (which > was made auto with some manual routing at the end so, not sure...). I > want to keep the 22pF capacitors as through hole (in that area are > many "veins") and I can try to use for the remaining, SMD variants. > Thank you for the tips. > > On Oct 30, 5:17 pm, vasile surducan <[email protected]> wrote: > > It looks good (haven't patience to look closer). However why did you mix > > through hole with smd? (except the connectors, use only smd onboard) The > > lenght can be reduced with at least 10-15mm if miniaturization is your > need. > > All vias are below the microcontroller, some people does not recommend > such > > tehnique, however I see no problem only if this board is factory > > manufactured. Maybe the board has a good purpose, which I can't see it > > because I have never used solderless breadboards and have no intention to > > use from now. > > > > Using a breadboard: > > - is not safe, has poor contacts, a lot of signal interferences, the > final > > stuff breadboarded can work different than the prototype (if the > breadboard > > user will manufacture a prototype after playing with wires) and that is > a > > good way of wasting time understanding if the bug is a software or a > > hardware one > > - the user is missing the key of playing hardware: learning soldering > > tehniques, learning PCB design techniques, understanding the bitter > relation > > between the initial ideea and the final product > > > > Vasile > > > > On Sat, Oct 30, 2010 at 6:17 AM, vasi vasi <[email protected]> wrote: > > > Hi guys, > > > > > I want to present you the smallest member of Jaluino, Jaluino CELL as > > > it was named by Sebastien. Look at it as a prototype and a proposal. > > > The board is designed to be used on a breadboard and for rapid > > > prototyping. > > > > > This version use the USB bootloader of Albert and use the red LED as > > > boot mode indicator. Right now the red LED is connected at RA4 pin but > > > I'm open to suggestions. Unfortunately, the space is very small and I > > > was forced to remove the jumper which allowed disconnection of the > > > LED. You can do that removing the limiting resistor (but is nice to > > > have a boot mode indicator). Also not all components fits on the top. > > > One diode and three resistors (all smd) are soldered on the bottom. > > > The green LED is for power indicator and the blue jumper is for power > > > select (USB or external). The external power must be 5V regulated. > > > Why no regulator on board? To be able to address any project, > > > with any consumption requirements. > > > > > The board don't have an ICSP connector (no more space) but having > > > external pins, the microcontroller can be easily programmed if you > > > insert the board on a breadboard (without the fear of bending pins). > > > > > Well, the initial version was a lot bigger but Sebastien suggested that > > > if can be of maximum 5cm long it can benefit from the cheapest > > > Seeedstudio service and I considered it a good advice.. > > > > > I hope that this board will be useful for someone. > > > > > -- > > > 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]<jallib%[email protected]> > <jallib%[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. > > -- 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.
