Struggling with bootloader onto TQFP atmegas
Topic: Struggling with bootloader onto TQFP atmegas
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Re: Struggling with bootloader onto TQFP atmegas
Mar 01, 2014, 07:38 am
I think I figured out the problem.. my board multiplexes the SPI bus to other ICs. I thought just disabling the MUX would be enough, but it seems to be still loading the pins. When I added resistors in series between the ICSP and MUX, as per:
the bootloader made it!
Out of curiosity, does anyone know what value R is appropriate here? The appnote doesn't give values, and I used 220R because they were on hand. Will check that the SPI still works as intended tomorrow.