Guru
Joined: 13/10/2014
Location: AustraliaPosts: 1688
| Posted: 05:38am 02 May 2024 |
Well the cheap USBASP programmer arrived.
Once I had it rewired, I was able to burn a new boot loader or upload a program using it. For program upload the inbuilt IDE software programmer via boot loader is noticeably faster- obviously.
The boot loader, the Nano with the old boot loader is now seen as a Nano with the new boot loader, and runs at a faster baud rate accordingly.
However, the problem with the these Nano boards remains, it's purely a problem in the hardware or the CH340. I am certain that the CH340 chip will not do anything until it is first connected to at 9600 baud, once connected you then release the port for other programs to use, once you do that, you can leave it sit for hours, it will then connect correctly and the baud rate change handshake responds to the baud request and life is good - it programs and verifies perfectly as before.
If you try to program it again - you fail - Why? - because the baud rate is no longer at 9600 after programming, so you can't initialize a new programming cycle, so back to 9600 first.
RECAP: These CH340 Nano boards will not respond to a baud rate request at anything other than a 9600 baud connection, after that, they run and program at normal high speed baud rates.
Changing the boot loader makes no difference to that behavior.
Nice to have the option of installing a new boot loader - or programming without a boot loader, that makes a few extra bytes available for programming.