Jim Hartmann

Coldfire eTPU Input Capture stops interrupting

Discussion created by Jim Hartmann on Jun 11, 2008
Latest reply on Sep 8, 2009 by Johan Bezem
I have an Input Capture channel with a 1kHz signal at the input. The CPU is running at 96MHz.  I'm using the eTPU api functions provided by Freescale.

The initialization call is:

fs_etpu_ic_init( TPU0,                                  FS_ETPU_PRIORITY_MIDDLE,                                  ETPU_IC_MODE_CONT,                                 FS_ETPU_TCR2,                                 ETPU_IC_RISING_EDGE,                                 333 )

The IC continues to work for long periods of time, interrupting every 333 cycles on the input.  At some point the IC stops interrupting the cpu even though none of the control registers for the channel have changed, interrupts are still enabled.  I observe in the parameter ram for the channel that the Transition count is still changing, but the Final time register value is static, during normal operation the Final time register is changing. 
Any clues as to why the IC stops interrupting the CPU?