Reviewing the data sheet and some app notes, AN2519, &c., the only inductor called for is 10uH tying AVcc to Vcc. In past, I never incorporated because of lack of knowledge and the myriad choices of components from a vendor…RF choke, EMI suppression, Power filtering? Bourns 78F series? Laird 28L’s? Although, app note AVR040, fig 4-3, there is illustrated an LC circuit, but nothing there specific enough to be of assistance to me.
So, back to the books, and reviewing this thread. I’ll get it, I’ll get it.
Thanks folks!
As an aside, I tried Eagle and Fritzing years back, and dropped it because of steep learning curve. For some reason KiCAD took to me with my first try. Probably more credit due the developers than to myself. Hehe.
@paulvdh, I am wondering what you did to make kicad display the 3D view? My pcbnew (version: 5.0.1+dfsg1-2~bpo9+1) only shows the PCB with silkscreen and plated through-holes when I bring up the 3D-Viewer–no components, just an unpopulated PCB. Same for your 3-3-19 revised version. Do you remember what you did to make the components show up in the 3D -Viewer as your photo shows?
@paulvdh, That worked splendidly !! thanks so much! It downloaded 338 MB in debian linux.
Thank you too for editting Bambuino’s PCB and for describing your revision well.
@paulvdh & al. I read on this forum other day that JLCPCB has online Gerber viewer, which does some error checking as part of the ordering process. I tried it out and got an error in the “Analysis” tab (photo 1). Being a newb, figured let slide until get other things worked out.
Been toiling away on my project, following @paulvdh 's very informative postings, above, using his version as reference and comparison. Took a break and tried JLCPCB’s online tool with his *.pro. I get two errors, the original Edge Cuts error, and a second, drill file error in re non-Gerber format (photo 2).
Can someone offer guidance in resolving this? If I was to submit order, I do not know if JLCPCB will reject based on these errors. In both instances I followed JLCPCB’s linked guide “KiCAD PCB to gerber files.”
The main to know is that ferryte beads are like inductors but with lo quality. At higher frequency inductors resonate but ferryte beads change RF energy to heat and not resonate. In power filtering it is better to not have something resonate so the first choise is ferryte bead. But if you are interested in filtering rather low frequency the ferryte bead is not good as it has rather low inductance and don’t work effectively at low frequency. 1MHz is low, 100MHz is high, but where exactly is the border betwean low and high - may be 10MHz but it depends on many things I think.
If I have a source of unwonted signal (like DCDC converter) I typically put two filtering stages at both sides of it. First - closer to DCDC with ferryte beads and ceramic capacitors (to filter as close to source as possible because high fregueny can use even a few cm of track to RF emmite) and second with inductors (100uH range) and electrolytic capacitors. I use 0603 1k ferryte beads (farryte beads are identified by their R at 100MHz) whenever possible (that means if their DC R is not too high). If DC R have to be very low than I look for less then 1k ferryte beads or for bigger then 0603 ones.
Yes, that’s the URL for the “KiCAD PCB to gerber files” page linked in the footer of their pages. Those are the guidelines I followed. Unsure if error or message, just not a green check mark. Just curious.
Make some errors on your PCB (Too small via’s, faulty PCB outline, traces outside Edge.Cuts, etc) and upload to JLC, and see if they get flagged.
I’m also curious what happens if you swap the filenames of a Silkscreen and a Copper layer.
Note: Ink does not conduct very well, and computers are stupid.
So, I opened symbol editor from Eeschema and dragged the hidden pin 22 to side (photo), tied it to pin 8. This then led to a grey label of my GND symbols as “GND 1”. There was no grey label when pin 22 hidden. Receive no ERC infractions on inspection.
Lots of greyed out GND pins in schematic symbols is a known issue in a lot of the library symbols. I’ve heard (more like “read” actually) that it’s a temporary thing and will probably improve with KiCad 6.
I did see a small bit of room for improvement in the PCB layout.
There were 3 traces between the 2 rows of pins in the top of this screenshot, but I rerouted MOSI to expand the GND plane between the THT pins on the top. This gives a shorter return path for the ISP connector currents. After that I saw I could easily move SDA and SCL to make the GND plane even more continuous, and I added a via for a continuous GND plane around the ISP connector.
These changes are pretty trivial for such a small and simple circuit as this, but for larger & compexer boards a lot of such details all add up.
Did you also remove the LED’s and replaced it with an experimental / kludge area?
With Oshpark you gat 3 or 5 boards, and that makes it easier to use all of your boards.
@paulvdh Yes, I wanted to move that 2x4 header closer to U1 to make tracks shorter than the 2.4 GHz antenna on the radio breakout. I think your mod makes that more practicable. Mahalo!
I got mired in self-tutor in re ferrite beads, inductors, &c. Seek advice (confirmation?) on possible choice ferrite for the L1 component in below capture.
Ferrite Bead With Axial Wire, 5A, 75 Ohms@100MHZ, DCR Max 0.01 Ohm Laird 28L0138-10R-10
This one I can stand up close to the chip, keeping C5 nearby as well.
AVCC is the supply of analog circuitry in U1. Such pin should get clear power. Analog circuitry typically don’t gets so high and short current pulses as digital circuitry. So the filtration is needed at lower frequencies than at VCC. Using here 10…22uH is typical, I think.
As ferryte beads has much lower L I would look for inductance and not ferryte bead here.
If you see that element you selected is for 5A and your AVCC pin gets probably few mA the red-light should lite-on in your head that you are probably doing something wrong. There are probably situations that it could be good choise but I don’t know such.
Look at characteristic of that ferrite bead at place where R is close to 0 and X and Z are the same line. I read that Z=8 ohm at 1MHz. From that you can calculate L=1,3uH (and the designer wonted 10uH).
