Funniest thing happened the other day. While uploading code to an UNO repeatedly as I tweeked it, it all of a sudden gave me the stk500 message.
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:\Users\owner\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf"
Using Port : COM7
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=0xb3
I tried a different UNO, same. Then a third. Same. I tried different USB cables. Checked port, all that, nothing.
Tried a Nano and first time it uploads without problem.
I can't figure out why it would have all of a sudden stopped uploading to the UNO.
Goto Tools>Board>Board Manage, you have the wrong board selected. Before you switch check which bootloader you are using for the Nano incase you want to switch back.
The board is correct. It's set to uno. I didn't oroginally do anything I can recall besides just upload the code. I don't know why it won't upload. I can't even upload a bootloader to it.
Try restarting your computer. In some rare cases, the port can get stuck in an unusable state. Restarting the computer restores the port to a usable state.
Running Arduino 1.8.19, Arduino AVR Boards 1.8.5. Here is what I have figured out so far. IDE is pointing to system wide configuration file "C:\Users\owner\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf" that isn't where it should be. There is no folder under \owner\ called \AppData\ I have reinstalled Arduino IDE but that didn't help. Here is the error:
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:\Users\owner\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf"
Using Port : COM7
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=0x2a
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x2a
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x2a
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x2a
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x2a
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x2a
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x2a
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x2a
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x2a
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x2a
avrdude done. Thank you.
Problem uploading to board. See https://support.arduino.cc/hc/en-us/sections/360003198300 for suggestions.
Skipping contributed index file C:\Users\owner\AppData\Local\Arduino15\ATTinyCore, parsing error occured:
com.fasterxml.jackson.core.JsonParseException: Unexpected character ('<' (code 60)): expected a valid value (number, String, array, object, 'true', 'false' or 'null')
at [Source: (FileInputStream); line: 7, column: 2]
java.lang.NullPointerException
java.lang.RuntimeException: java.lang.NullPointerException
at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onUpdatePressed$1(ContributionManagerUI.java:150)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException
at cc.arduino.contributions.packages.ui.ContributionIndexTableModel.lambda$updateContributions$1(ContributionIndexTableModel.java:90)
at java.util.TimSort.binarySort(TimSort.java:296)
at java.util.TimSort.sort(TimSort.java:221)
at java.util.Arrays.sort(Arrays.java:1512)
at java.util.ArrayList.sort(ArrayList.java:1462)
at java.util.Collections.sort(Collections.java:175)
at cc.arduino.contributions.packages.ui.ContributionIndexTableModel.updateContributions(ContributionIndexTableModel.java:89)
at cc.arduino.contributions.packages.ui.ContributionIndexTableModel.update(ContributionIndexTableModel.java:183)
at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onUpdatePressed$1(ContributionManagerUI.java:148)
... 1 more
Skipping contributed index file C:\Users\owner\AppData\Local\Arduino15\ATTinyCore, parsing error occured:
com.fasterxml.jackson.core.JsonParseException: Unexpected character ('<' (code 60)): expected a valid value (number, String, array, object, 'true', 'false' or 'null')
at [Source: (FileInputStream); line: 7, column: 2]
There is. It is just hidden by the default settings of Windows "File Explorer. You can make it visible by opening the "View" menu, then checking the box next to "☐ Hidden items".