Hi!

My problem is that my processor only runs stable at round 96Mhz. When setting the processor clock to 110Mhz it randomly freezes within 5 minutes (or in a few seconds).

It is a two layer board, maybe this is causing the instability? I've assembled the PLL section of the board using 10% tolerance components, maybe this is causing the problem? the supply voltages seem to be stable, so I guess this is not the problem.

however, how can I check that the PLL and clock circuit is working properly? how to check weather grounding is OK? what other things can cause instability like this?

the board runs linux more or less stable (when there is heavy load on the processor, linux does a kernel oops.)

Can anyone give me some pointers how to solve such issues?

I'd be very grateful if anyone could post me a reply.Thank you.

Best regards:Zo

Hi Zoldnap,

For you or other guys, here are some advices:

- To check the PLL clock, you can use PCK output (see the datasheet for that),
- To check the Peripheral Clock, you can use USART, and specially, in synchronous Mode and display the Serial Output clock in order to be sure about the working frequency of the Peripheral Clock,

About your issue, I remenber you the Peripheral Clock cannot be upper than 80 MHz instead of the processor clock (up to 200 MHz). I think it is the cause of the hang up.
Now some advices to work over 80 MHz at processor level:
When the processor is booting up, the processor is in Fast Mode Bus (processor clock is equal to bus clock). You have to select a bus clock up to 80 MHz and the processor clock up to 200 MHz at PMC level and after select a asynchronous Mode at processor level. Look at the ARM9 User Guide in order to switch from a Fast Mode Bus to Asynchronous Mode. These information are not in AT91RM9200 Datasheet.

Hope this helps