Hello,I am currently working on a ARM9 based System on Chip. I would like to experiment with Frequency scaling on the CPU, but I have the following issue:The main PLL is used at the same time by an hardware codec, and the ARM ... So I was wondering if there is any internal PLL on the ARM9 which would allow me to perform DVFS without touching this main PLL ?At first sight, the reference manual doesn't mention any, but maybe I misread it ...
Regards,
Nicolas DEROUINEAU
Although I can probably not answer your question (because I am not very experienced with ARM9), I think others may be able to answer it, if you can be more specific on the manufacturer and part number.
I do believe that most (if not all) ARM9 have a PLL, but the way they're implemented might differ from manufacturer to manufacturer and from part number to part number.
-For instance, a LPC1768 from NXP (which is Cortex-M3) may have a different PLL than LPC1788 from the same manufacturer, even though the LPC1788 is also a Cortex-M3. I believe it's similar with ARM9.