Greetings,
I have an Arduino R3 UNO (MEGA328p + Holtek HT42B534) which was working just fine unitl a few days ago. Then I got the avrdude: stk500_recv() error.
I have sucessfuly uploaded bootloader with USBasp with Arduino IDE. Still I have the same error trying to upload through USB.
Then I have sucessfuly uploaded "Serial event" example with my USBasp and to test the serial RX, TX through my USB connection and it works I get the TX reply.
But still uploading though USB connection gives me the sam error as below (is it the upload baudrate 115200 issue,can I lower it?):
C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avrdude -CC:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf -v -patmega328p -carduino -PCOM3 -b115200 -D -Uflash:w:C:\Users\Marko\AppData\Local\Temp\arduino_build_196512/BareMinimum.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 : COM3
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x7b
do you have something else hooked up to rx and tx pins while uploading ?
HI,
No, just bare board, nothing connected to it, except USBasp or USB cable when trying to upload.
could you try disconnecting the USBasp while uploading ?
Hi,
If you think I have USBasp connected to my arduino board while trying to upload through USB cable, I do not. Or did you mean something else?
is the loopback test working ?
I am not 100% sure how to make one.
Could you guide me or show me a link on how to make one?
Thanks.
sorry I didnt get you what did you mean by make one ? 
Some positive result!
I was able to upload through USB using this procedure:
-Disconnect the usb connection
-Begin holding the Reset button
-Connect the Arduino
-Initiate upload (while still holding Reset continuously)
-As soon as you see the RX light flash, release the Reset button.
Without this procedure upolad does not work thrugh USB.
I have searched for loopback procedure, assembed one, but serial monitor does not give no TX answer.
If it works while pressing the reset button means your board have some problem with usb to serial chip (atmega16u2) resetting the atmega328p or maybe any problem with the bootloader (less possibility). I hope you bootloaded it through the arduino ide itself right ?
Yes, I uploaded bootloader through Arduino IDE using USBasp, standard procedure.
Well, as long as I can upload, using RESET button, I can live with it.
Thank you for your time and effort.
Once I also got the problem as you mentioned but I reflashed my atmega16u2 with my usbasp solved for me. so could you do it too ?
Hi,
How should I do this exactly?
Would you explain it to me, please?
I'm a noob here, learning as I go.
