xinqi wang

Actual bus frequency of MC9SDT256B?

Discussion created by xinqi wang on Jul 8, 2009
Latest reply on Aug 5, 2009 by Processor Expert

I have two sets of MC9SDT256B based systems. oscillator freq. 4.0Mz. so bus frequency should be 2.0Mz with PLL clock "disabled". After I build up a project with codewarrior. Codewarrior waywardly

sets the internal bus clock 8.0Hz. If I set up my timers literally according to the real value. i.e. I need

PWM frequency 45Hz. I setup PMW frequency in codewarrior 45Hz.I would get 11.0+Hz. Also, my pulse

width measurement also shows the reading pulse width is 4 times as the real ones.  This seems not quite right although I can justify manually. Please check the attached screen shot of the setup.

What mistakes could I make?

Any response would be really appreciated




Message Edited by t.dowe on 2009-09-04 03:12 PM