About PCLK

Hi,

I have bought a LandTiger development board for LPC1768. it has a 12Mhz Xtal on it. I am trying to use its USART0 and I need to know PCLK. is it 3MHz? I devide 12 by 4. am I right?

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  • Any reason why you run the processor so extremely slow - are you running on batteries?

    The 12MHz crystal is normally first upscaled by a PLL so you might get a CCLK of 100MHz or something like that. But let's say the PLL is configured to scale the FOSC = 12MHz crystal giving a CCLK of 60MHz. Then a division by four would give the UART a PCLK of 60/4 = 15MHz.

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  • Any reason why you run the processor so extremely slow - are you running on batteries?

    The 12MHz crystal is normally first upscaled by a PLL so you might get a CCLK of 100MHz or something like that. But let's say the PLL is configured to scale the FOSC = 12MHz crystal giving a CCLK of 60MHz. Then a division by four would give the UART a PCLK of 60/4 = 15MHz.

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