AnsweredAssumed Answered

M52259DEMO operating at the wrong speed

Question asked by Colin Bathe on Apr 22, 2010
Latest reply on Oct 19, 2010 by Walter Muth

Hi,

 

I've recently purchased a M52259Demo and have been playing with the Processor Expert both with supplied demos and from projects I've started from scratch. With both of them I'm having problems with the board running approx x5.5 slow when using the external 48MHz crystal.

 

Taking this project as an example:

C:\Program Files\Freescale\CodeWarrior for ColdFire V7.1\(CodeWarrior_Examples)\Processor_Expert_Examples\M52259EVB\Init_GPIO,

I simply change the Remote Debug to Coldfire V2-V4 JM60 OSBDM then compile and run. Unfortunately, I get junk on the serial port (set correctly to 38400,8,N,1) and the LED flashes three times slowly.

If I change the High Speed Clock in the CPU bean from external to internal, everything bursts into life correctly. The LED flashes at a sensible speed and the serial port produces the expected text.

 

In my own project, I have used a timer driven interrupt to flash an LED and a PWM channel to flash a different LED. Both methods run a factor of x5.5 slow on the external clock and at the correct speed when using the internal clock. The external clock input is set to 48MHz - unchanged from the defaults.

 

Is this likely to be me not pressing a button correctly somewhere or is it likely to be down to me having a duff demo board?

 

Thanks in advance for any help given!

Outcomes