**tonau** wrote on Tuesday, July 28, 2009:

Hi all,

i found a value off 47923200 for configCPU_CLOCK_HZ. But i think it must be 48054841.

Here is the calculation taken from James P. Lynchs AT91SAM7 Serial Communications:

MAINCK = 18432000 Hz crystal frequency

DIV = 14 (set up in lowlevelinit.c)

MUL = 72 (set up in lowlevelinit.c)

PLLCK = (MAINCK / DIV) * (MUL + 1) = 18432000/14 * (72 + 1) (phase lock loop clock)

PLLCLK = 1316571 * 73 = 96109683 Hz

MCK = PLLCLK / 2 = 96109683 / 2 = 48054841 Hz (main clock MCK)

This calculation rounds after every step of calculation. I think this is right if only integer values are used by the SAM7X to calculate the PLLCLK.

So what value is the right one? Has anyone a calculation with 47923200 as result?

Thanks!