diff --git a/configs/demo9s12ne64/include/board.h b/configs/demo9s12ne64/include/board.h index 9420b67ddb..ee190731cb 100755 --- a/configs/demo9s12ne64/include/board.h +++ b/configs/demo9s12ne64/include/board.h @@ -51,9 +51,30 @@ ************************************************************************************/ /* Clocking *************************************************************************/ +/* Frequency of the crystal oscillator */ #define HCS12_OSCCLK 16000000 /* 16MHz */ +/* PLL Settings + * + * SYNR register controls the multiplication factor of the PLL. If the PLL is on, the + * count in the loop divider (SYNR) register effectively multiplies up the PLL clock + * (PLLCLK) from the reference frequency by 2 x (SYNR+1). PLLCLK will not be below + * the minimum VCO frequency (fSCM). + * + * The REFDV register provides a finer granularity for the PLL multiplier steps. The + * count in the reference divider divides OSCCLK frequency by REFDV + 1. + * + * PLLCLK = 2 * OSCCLK * (SYNR + 1) / (REFDV + 1) + * + * If (PLLSEL = 1), Bus Clock = PLLCLK / 2 + */ + +#define HCS12_SYNR_VALUE 0x15 +#define HCS12_REFDV_VALUE 0x15 +#define HCS12_PLLCLK (2*HCS12_OSCCLK*(HCS12_SYNR+1)/(HCS12_REFDV+1)) +#define HCS12_BUSCLK (HSC12_PLLCLK/2) + /* LED definitions ******************************************************************/ /* The DEMO9S12NE64 board has 2 LEDs that we will encode as: */