PIT initializing in MPC860

Joel Sherrill <joel@OARcorp.com> joel.sherrill at OARcorp.com
Thu Jan 22 23:40:15 UTC 2004


Brett Swimley wrote:
> 
> 
> Joel Sherrill wrote:
> 
>>
>> If I remember the problem correctly, you have to know the
>> clock frequency to select the proper divider and this is
>> all done inside the BSP at compile time.  Is there a way to
>> probe for the clock frequency being used?
>>
>> If not, would it be feasible to have a BSP specific configure
>> option to specify the clock information?  And use some default
>> value otherwise based upon the BSP model variant?
>>
>> I do just that with my BSP.
>>
>> I have the following in my linkcmds file:
>> /*
>> * Default Clock Speed at 48 MHZ
>> */
>>
>> _CPUClockSpeed = DEFINED(_CPUClockSpeed ) ? _CPUClockSpeed : 48000000;
>>
>> Then, to override in my Application specific Make file:
>>
>> # change the clock rate
>> AM_LDFLAGS += -Wl,--defsym -Wl,_CPUClockSpeed=64000000

I should have remembered this trick.  It is much easier
and cleaner.

Thanks for reminding us.

>>
> 


-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel at OARcorp.com                 On-Line Applications Research
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