Difficulties when burning bootloader with Arduino as ISP (Mini/Mighty/MegaCore)

[MCUdude]

See MiniCore #115 for more details.

It's impossible to set the upload baud rate for the bootloader when burning bootloader with Arduino as ISP. this is because ArduinoISP relies on upload_speed = 19200 to work. However, when this is specified, a bootloader with a baud rate of 19200 is always selected, no matter what board_upload.speed is defined to.

• board_upload.speed should be used when doing "regular" uploads using -carduino as upload protocol (using a bootloader).
• upload_speed should be used when the user is uploading using a programmer to upload, or setting the fuses/burning bootloader.

This is only an issue with programmers that uses a serial port and a baud rate to communicate with Avrdude. @ivankravets @valeros I guess it should be an easy fix.

[valeros]

Sorry for the late reply. Basically, board_upload.speed and upload_speed represent the same thing - the baudrate which uploader uses for sending firmware to a board. As I understand the problem, we cannot select a bootloader image since upload_speed is used as part of the bootloader image name. What do you think if we introduce a new field to bootloader section, e.g.:

board_bootloader.speed = 115200

that can be used for choosing the right bootloader image? If it's not specified then we will fall back to upload_speed value.

[MCUdude]

Sorry for the late reply.

No worries! I do understand that you have a lot to do. You should know that I really admire this project and all the work you and Ivan have put into this project 🎉

Maybe we could combine this with other improvements as well. Here's another thing that's a little annoying.

Let's say I've created a project where I use a USB to serial adapter for uploading. However, if I want to bootload the board I've connected, I'll have to add my programmer to platformio.ini as well. Just like this:

; Upload using programmer
upload_protocol = usbtiny
; Aditional upload flags
upload_flags = -Pusb

I can now set fuses/burn bootloader. However, if I want to upload using my USB to serial adapter, I will have to uncomment these two lines to prevent them to "interfere" with regular UART uploads.

it would be great if we would use the board_hardware.uart field to determine if the standard upload command (I'm using the ➡ arrow button in VSCode) would trigger a UART upload or a programmer upload. If so, one could be able to do both without having to uncomment lines in the ini file. What do you think?

As I understand the problem, we cannot select a bootloader image since upload_speed is used as part of the bootloader image name.

That is correct. I like your idea, but could you make work no matter what is present in the ini file, like so?

ONLY board_upload.speed PRESENT
Use value for both bootloader and upload speed

---------------------------------------------------

ONLY board_bootloader.speed PRESENT
Use value for both bootloader and upload speed

---------------------------------------------------

BOTH PRESENT
Use board_bootloader.speed for bootloader speed and
board_upload.speed for upload speed

[valeros]

it would be great if we would use the board_hardware.uart field to determine if the standard upload command (I'm using the arrow_right arrow button in VSCode) would trigger a UART upload or a programmer upload. If so, one could be able to do both without having to uncomment lines in the ini file. What do you think?

Not sure about this, board_hardware.uart option is mainly used with your cores and upload_flags option might be used for UART upload as well. Besides, in most cases burning fuses/bootloader is one-time operation, right?

ONLY board_bootloader.speed PRESENT Use value for both bootloader and upload speed

In the most cases, it's not an option since board_upload.speed is always present (set by a user or default value from a board manifest).

[MCUdude]

Not sure about this, board_hardware.uart option is mainly used with your cores and upload_flags option might be used for UART upload as well. Besides, in most cases burning fuses/bootloader is one-time operation, right?

OK, at least my idea is not thought through yet. We can leave this for now and focus on the other thing.

In the most cases, it's not an option since board_upload.speed is always present (set by a user or default value from a board manifest).

Yes, that is right, sorry. Then I think we agree. Use board_bootloader.speed is present to get the correct bootloader file. If not, use board_upload.speed. OK?

[MCUdude]

Thank you! Will give this a try very soon. I'll report back if I find any issues 🙂