mpc5554 eTPU Input Capture missing edges in negative range of count

[peterszymanski]

Hi, I'm using the eTPU set downloaded from Freescale/NXP after using the feature selector. I'm using the Input Capture function and find that it stops tagging edge times when the internal count of edges received is over 0x7FFFFF counts. It starts up again after the 24 bit count rolls back to zero. What am I doing wrong that it does not provide edge times in the "negative" range of the 24 bit count? Thanks

[peterszymanski]

Thanks for the feedback.  That shed some light on the problem.

Ok, I've looked at some of the source that came with the eTPU set that we downloaded.  It appears that all of the code uses the GreaterEqual setting.  From David's comment, am I correct in assuming that the code set would need to be recompiled using the EqualOnly setting?  Is there a version from Freescale/NXP that can be downloaded with the EqualOnly setting?  Or do we need to get the ByteCraft compiler and recompile ourselves?

BTW, I tried changing my timebase from TCR1 to TCR2 but the input capture exhibited the same response.  That's what led me to examine the code set and where I saw the GreaterEqual settings.

[davidtosenovjan]

It will be due to greater-or-equal to comparator mode selected by default.

Here there is screenshot from some old TPU presentation (it uses 16-bit counter). eTPU uses 24-bit counter thus MAXIMUM future value is TCR + $800000.

Also I am attaching screenshot from eTPU manual: