Accessing Comparator Hangs Serial on Teensy 3.1

[tlb]

I am trying to use the comparator on Teensy3.1. I am talking to Teensy over USBSerial. If I do any accesses to the comparator, Serial will not initiate, even if the comparator code is after the Serial.begin(9600).

The program works fine, and then if I add the line:

uint8_t testVar;
testVar=CMP0_SCR;

serial will not initiate. Any ideas? I have additional comparator code which also hangs the system, but even this minimal read does it.

Thanks much,

TLB

 

[pictographer]

Try this thread: Teensy 3.1 and CMP0 or CMP1 modules - lockup

 

[PaulStoffregen]

Almost everything in the chip defaults to powered down. If you try to use something without first turning it on, you get a hard fault.

 

[tlb]

Thanks. I had noticed this post before but couldn't find it again.