@lore @PawelK It would be helpful in the near future. The SPI issue could be related to a feature on the board itself. It might require something more powerful to get it in the correct mode.
One thing I do when working with hardware is print out the relevant documentation and use crayons or color pencils to mark important sections. It really helps.
The other thing that comes to mind is the 16mhz xtal on the Uno. It's possible that it is just not fast enough to properly communicate.
Damn, we had similar issue with audio on one of tom-toms.
@PawelK @lore I could see that being an issue. It's always the smallest of details that cause the biggest of headaches.
There were people who used a CP2012 or similar adapter and had the same problem with the Blackfin. It's likely a configuration issue.
After this many stumbling blocks, I would just go with Open Source tools. I'm fairly certain that Debian Linux has support for the needed tools to deal with the Blackfin.
@AmpBenzScientist @PawelK using the WRONG pin on the Blackfin fixed the problem. the pin headers on the Blackfin match the Arduino pin-for pin and the schematic says that pin 10 and 9 are both connected to the SS pin on the Blackfin via resistors. but pin 10 does nothing. i tried shorting it to GND and 5V and nothing. but pin 9 works. that's a random GPIO pin on Arduino though. i don't see how that's even supposed to work.