Hello forum! I now spent multiple hours on this and can't seem to find the problem...
Setup
Arduino IDE 2.3.6
Board: Arduino Pro Mini 5V/16MHz (clone)
Using FTDI232 board as programmer
I am following this instruction with the same hardware:
Problem
The setup worked as expected with the stock bootloader it came with.
However, for my application I want to code to start fast once power is supplied. Unfortunately this is not the case with the preinstalled bootloader, which takes about 2s after power on until the sketch starts.
On this forum I found a hint that Optiboot eliminated that additional time on power-up. Following the trail on github it directed me to MCUdudes MiniCore, which in turn uses Urboot.
I successfully flashed MiniCore using ArduinoISP using an Arduino Uno.
Settings:
- Baud Rate: Default (also tested 57600)
- BOD: 4.3V
- Bootloader: Yes (UART0) Clock: External (16 MHz)
- EEPROM retained
- Compiler LTO enabled
However, with the MiniCore bootloader in place, I cannot program the Pro Mini anymore using the normal upload function. 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\Seilo\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf"
Using Port : COM4
Using Programmer : arduino
Overriding Baud Rate : 57600
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xa0
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x77
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0xa0
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x77
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0xa0
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x77
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0xa0
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x77
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0xa0
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x77
avrdude done. Thank you.
Failed uploading: uploading error: exit status 1
What I also tried:
- To cross-check, I switched the Pro Mini with another one (old bootloader, leaving the rest of the setup as-is) and all works as expected. This hints to me, that the FTDI232 programming might not be supported with MiniCore bootloader. Is that correct? I read something about a different reset timing. Might that be the problem? I am using the DTR output of the FTDI.
- Rolling back to the Arduino standard bootloader, everything works fine
Please let me know if any info is missing, I'll supply that.