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BDM debugging (step over) speed.

Question asked by Eric_t d on Sep 17, 2018
Latest reply on Sep 19, 2018 by Daniel Martynek

Hi!

Am using codewarrior 5.1/5.2 and mc9s12xeq512 controller.
The borad has a crystal of 16MHz and PLL of 50MHz.
I have a problem with the step over speed.
It takes from few milisecond to 4 seconds.
Most of the times the step over speed is about 1.5 second.
Of Course the complexity of c line have effect on step over speed, but with 50MHz bus clock, the 1.5 seconds and the 4 seconds of step over is way to long (even PIC16Fxxx is faster).
When I disable the PLL, the clock bus is only 8MHz, but there is no noticable change of the debugging speed.
This tells me that BDM uses the crystal oscillator and not PLL.

The CLKSW bit of BDMSTS, controls which clock the BDM operates with, and it is only writable from a hardware BDM command.
As far as understand, if PLLSEL=1 and CLKSW=1, the BDM Clock Source, dependent on the PLL.

 

Does anyone know how can I set CLKSW, so the BDM will work with the PLL.

 

Thank you.

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