I have 2 boards which are the same, both use a teensy 3.6 and DAC8562. On one of them the DAC would not start. the Sync(CS), Clock, and Data signals to the DAC looked the same on a scope, but the non working one had no voltage appearing on the VREF pin after the "use external VREF" command was sent via SPI.
The strange thing was that swapping the DACS, the problem still happened on the same board/teensy that was not working before.
After trying a lot of changing ISR, SPI, clock speed, Re-ordering commands in setup, and adding delay()s. i finally found something that worked. Repeating the "use internal VREF" SPI command to the DAC8562.
The only reason i can think of why that would happen is that the SPI bus is somehow not "woken up" on the teensy that was having the issue.
Fortunately it turns out not to be a problem after the fix, but it was a bit perplexing trying to fix it!
Was there a revision of the MK66 or that might cause that?
The strange thing was that swapping the DACS, the problem still happened on the same board/teensy that was not working before.
After trying a lot of changing ISR, SPI, clock speed, Re-ordering commands in setup, and adding delay()s. i finally found something that worked. Repeating the "use internal VREF" SPI command to the DAC8562.
The only reason i can think of why that would happen is that the SPI bus is somehow not "woken up" on the teensy that was having the issue.
Fortunately it turns out not to be a problem after the fix, but it was a bit perplexing trying to fix it!
Was there a revision of the MK66 or that might cause that?