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Posted by leviatan1 on May 13, 2014

Hello, i have some troubles understanding the specification for

#define configCPUCLOCKHZ ( ( unsigned long ) 66000000 ) /* = Fosc/2 */

in the dsPIC30F.

lets asume i use XT=10 Mhz and PLL= x8 , i will have 80 Mhz. NOW, the Fosc/2 would be 40 Mhz? or am i wrong?


Posted by rtel on May 13, 2014

I just looked at the official demo, and in that it is hard coded to 25000000.

I think in this port you just have to set the constant to whatever frequency the CPU is running at, but there is probably more than one clock source for the CPU. In the official demo it looks like the CPU is driven by Fosc, and that Fosc is being divided by two before it drives the CPU. If you application drives the CPU from a different clock source then you will have to change the constant accordingly.



Posted by leviatan1 on May 13, 2014

if you say that Fosc drives the CPU and its divded for 2 before entering the cpu the correct frquenci in the config seems to be 40 Mhez in my case, i thank you sir.

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