Sync error when uploading to ATMEGA 328P

Hello,

I used “From Arduino to Microcontroller in a Breadboard” tutorial last year and it worked fine.

Now I have a new project, with the same breadboard and components, and I am getting

avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x3f

I use Arduino Uno R3 (two boards) as programmer
Ide is 1.8.13

I tested all solutions in this forum with no chance.

  1. To feed from an external source,
  2. To install two more capacitors in VCC & and 20,
  3. To test micros programmed in other boards, that r5.un OK in the breadboard
  4. To play with reset line as suggested,
  5. To test two different micros that run Ok in their R3 boards

I will paste the error lines that I get:

Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes.
C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avrdude -CC:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf -v -patmega328p -carduino -PCOM9 -b115200 -D -Uflash:w:C:\Users\HBB\AppData\Local\Temp\arduino_build_100531/Blink3.ino.hex:i

avrdude: Version 6.3-20190619
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2014 Joerg Wunsch

System wide configuration file is “C:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf”

Using Port : COM9
Using Programmer : arduino
Overriding Baud Rate : 115200

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x3f
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x3f

Thank you !
Horacio

stk500_getsync