M52223EVB Relaxation Oscillator

soccermike — Fri, 15 Jun 2007 06:04:46 GMT

Using the M52223EVB board, I'm trying to use the on-board relaxation oscillator. When I configure the jumpers, it appears that my on-board oscillator is running at 14MHz. Additionally, the Coldwarrior Debugger can't modify the ROCR bits TRIM[9:0]. Since the trim is close to the nominal frequency and all the values read back as 0%, this may be the source of the value. How do I change he ROCR bits?

I also found that CLKSRC functionality doesn't exactly match Figure 5-1. Clock Module Block Diagram.
The diagram shows both the Reference Clock and the PLL come after the Pre-Divider controlled with CCHR. Instead, I found (and it makes sense) that the Reference Clock comes directly from the CLKMOD0 mux.

Lastly, this diagram should include how OSCSEL affects the clocks.

Thanks in Advance,

Mike

Re: M52223EVB Relaxation Oscillator

macl — Fri, 15 Jun 2007 21:58:08 GMT

Hi Mike,

If the on-board oscillator is 14MHz, then I suspect it is from a small batch of EVBs that went out with initial samples that didn't have the oscillator trimmed correctly. I recommend returning the board to the distributor (or Freescale, if you bought it direct) and get a new one. It is not possible to write to the trim bits.

On your recommendations for the clock module block diagram, I will forward your suggestions to the documentation team. Thanks for the feedback.

Mac

ColdFire/68K Microcontrollers and ProcessorsのトピックM52223EVB Relaxation Oscillator

M52223EVB Relaxation Oscillator

Re: M52223EVB Relaxation Oscillator