I've been strugling with this issue for quite some time now, so lets see if someone from the forum can help.
I have a working PCB with ATMEGA328P. I used to download the optiboot_atmega328.hex boatloader in the ATMEGA 328P-AU (tqfp 32 package) and then upload sketches via the Arduino IDE. This worked well!
Now (and I've tried 3 different resellers) the -AU seems to be replaced by the U-TH suffix.
For instance I ordered these from Farnell:https://nl.farnell.com/microchip...
Farnell answers in a reply: right now this chip seems to be replaced by a chip with another inscription with U-TH on the end. (see photo).
I've contacted the chip manufacturer but they didn't respond.
Problem: with this chip variant (if it is a variant? I can't find out) the bootloader optiboot_atmega328.hex still goes in ok, but the uploads from sketches from the Arduino IDE won't work anymore.
Verbose messages are:
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x3a
Recently I have ordered an Arduino nano-mini which uses the same AU chip from the picture as reference. When it came in, I saw it is also using the same U-TH suffix. This board does upload the the bootloader optiboot_atmega328.hex as Arduino IDE sketches well.
Now it looks to me there is a hardware problem but I can't find out a functional difference between the nano-micro board and my own board. And because on the nano board the the bootloader optiboot_atmega328.hex bootloader works fine, this also shouldn't be the problem.
I also tried multiple upload cables (I'm using USB FTDI cables).
Since my hardware did work fine with the -AU versions, I could really use some advice!
See attached schematics.
Does someone knows how to solve this issue?
Is another bootloader or hardware modification necessary?