I'm reasonably new to Arduinos but recently became aware of the 2S delay at boot up. It seemed optiboot has a delay in mS so attempted to load it into a ProMini 5V 16MHz.
I'm using a UNO-R3 as the ISP and while I've tried several approaches (all with the same result) I'm currently sticking with Minicore. After burning the bootloader the ProMini shows 2 quick flashes every second which implies to me the bootloader has installed correctly.
Is this assumption right?
The problem is after burning optiboot, using my FTDI programmer it fails to upload sketches (i'm just using the Blink sketch for testing purposes). The verbose output is as follows:
Arduino: 1.8.10 (Windows 10), Board: "ATmega328, Yes (UART0), EEPROM retained, 328P / 328PA, BOD 2.7V, LTO enabled, External 16 MHz" Sketch uses 880 bytes (2%) of program storage space. Maximum is 32256 bytes. Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes. C:\Users\Scott Wilson\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino18/bin/avrdude -CC:\Users\Scott Wilson\AppData\Local\Arduino15\packages\MiniCore\hardware\avr\2.1.3/avrdude.conf -v -patmega328p -carduino -PCOM10 -b115200 -D -Uflash:w:C:\Users\SCOTTW~1\AppData\Local\Temp\arduino_build_984247/Blink.ino.hex:i avrdude: Version 6.3-20201216 Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/ Copyright (c) 2007-2014 Joerg Wunsch System wide configuration file is "C:\Users\Scott Wilson\AppData\Local\Arduino15\packages\MiniCore\hardware\avr\2.1.3/avrdude.conf" Using Port : COM10 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=0xbd avrdude done. Thank you.
I know the hardware setup is correct as I can restore the original ProMini bootloader using the same process and upload sketches via the FTDI programmer. I can also upload a sketch to the ProMini (without a bootloader) via the UNO-R3 using "Upload Using Programmer" option successfully.
I've read many posts related to this topic but unfortunately none of the solutions have worked for me. I've also tried installing the IDE & Minicore on another PC which produced the same failure.
I'm hoping someone out there may be able to offer some advice please.