Newbie to arduino here, mainly hardware person. I have a request for the IDE development team to consider a mod.
Since this is my first time using IDE, I didn't know about the idiosyncrasy of pin D13 with respect to the LED use by the boot loader. I happen to have connected a relay to that pin so when I download a sketch, it sings until the download is complete. If I update the shield I built for this application, I will move the relay to a different pin.
My suggestion is to have a configuration option in the IDE to disable the use of the LED by the boot loader & leave the pin as an input.
If there is another way around this, please let me know, I'm using an arduino uno R4 WIFI.
The IDE normally has no way to modify the bootloader behavior, short of "burn bootloader."
disabling the LED use in the bootloader is already possible by recompiling optiboot or urboot (actually, there is probably already a pre-compiled urboot among the 17e6 pre-compiled urboot .hex files that doesn't do anything with the LED.)
Then you just replace the .hex file in the appropriate IDE directory with the modified one, and use "burn bootloader" with an appropriate programmer.
(and if you have that "appropriate programmer", you can always use "upload using programmer" and eliminate the bootloader entirely.)
Thanks, That would work if I have a new shield made this time but I have another project coming up where all the pins will be used as outputs & I can't disable any outputs e en during bootloading. Sounds like westfw has the best answer yet!
You are welcome. If you decide to make a modified bootloader, you will also find these instructions for flashing your UNO R4 WiFi with the binary you build to be useful:
oops. I missed that.
It would have been nice if the R4 boards had used a dedicated LED for the bootloader activity. There are certainly enough pins (or it could have used one of the pins in the matrix.) (although I guess staying compatible with the D13 used on previous Uno boards has advantages too.)
If you do modify the bootloader to not use d13 , it might be useful , for others , to publish it so it can be used by others - or even detailed instructions of how to do it .
