| Electronics > Beginners |
| Pulling my hair out. Circuit boards stop working once shipped to client and more |
| << < (15/21) > >> |
| Ian.M:
OTOH that particular FTDI Windows driver quirk will definitely cause AVRDUDE to fail to communicate with a serial bootloader in an ATmega, without any other evidence of why its failed. If you are even slightly suspicious of the authenticity of a FTDI USB<=>serial chip, you are using a Windows PC, and the FTDI driver is more recent than the 'FTDIgate' event, doing that loopback test is essential. Don't bother if you are using Linux or a Mac - its a Windows driver only issue. If you still have FTDI on your 'design in' list in spite of their shenanigans, and you aren't a big enough player to buy direct from FTDI to avoid supply chain contamination, IMHO its essential to design your board to make it easy to do that loopback test - a loopback jumper would be a reasonable choice. Another possibility with FTDI clones is failure at higher baud rates. It only takes one lost or corrupted character in a few thousand to totally screw up bootloading, so you may wish to try a lower baud rate. However the bootloader *MUST* support the baud rate you chose as both ends need to match. |
| NivagSwerdna:
This is a fun thread... it has something for everyone and not enough information for any proper conclusions... .. The schematic showed a ICSP header... I presume that is what is being used to program the uP? The requirements for ICP are minimal... if it isn't working on Rev3 boards you either have some extra shorting to ground (due to errant ground pour) or dodgy chips. Ignore any talk about Flux, ESD etc... until all the obvious has been eliminated. For now just use a multimeter on continuity to determine if any ground shorts on Rev3 boards. |
| Jackster:
--- Quote from: NivagSwerdna on June 08, 2019, 10:29:43 am ---This is a fun thread... it has something for everyone and not enough information for any proper conclusions... .. The schematic showed a ICSP header... I presume that is what is being used to program the uP? The requirements for ICP are minimal... if it isn't working on Rev3 boards you either have some extra shorting to ground (due to errant ground pour) or dodgy chips. Ignore any talk about Flux, ESD etc... until all the obvious has been eliminated. For now just use a multimeter on continuity to determine if any ground shorts on Rev3 boards. --- End quote --- Yes the ICSP header is for programming. I can't find any pins on the MCU that are grounded that should not be. |
| mcinque:
--- Quote from: NivagSwerdna on June 08, 2019, 10:29:43 am ---it has something for everyone and not enough information for any proper conclusions... --- End quote --- In my opinion it lacks of something. Not enough data. I renew my offer: PM complete schematics and at least a flowchart principle of operation (not the sketch) toghether with failure symptoms (what should do and what instead do the board). |
| thinkfat:
If you look at the top of package of the Atmega from LCSC, it looks like the chamfer is a lot thinner, close to nonexistent. Were I to venture a guess, I'd say the top face of a chip has been milled or ground down a few thou to get rid of the marking and then a new marking has been stamped on. It's hard to see on the photo, however. To get a better image, maybe wet the chip with IPA and try a different light angle. |
| Navigation |
| Message Index |
| Next page |
| Previous page |