Hi Niklas, thanks for this work! > +/* > + * Linear approximation for temperature > + * > + * [reg] = [temp] * a + b => [temp] = ([reg] - b) / a > + * > + * The constants a and b are calculated using two triplets of int values PTAT > + * and THCODE. PTAT and THCODE can either be read from hardware or use hard > + * coded values from driver. The formula to calculate a and b are taken from > + * BSP and sparsely documented and understood. > + * > + * Examining the linear formula and the formula used to calculate constants a > + * and b while knowing that the span for PTAT and THCODE values are between > + * 0x000 and 0xfff the largest integer possible is 0xfff * 0xfff == 0xffe001. > + * Integer also needs to be signed so that leaves 7 bits for decimal > + * fixed point scaling, which amounts to a decimal scaling factor of 100. > + */ > + > +#define SCALE_FACTOR 100 > +#define SCALE_INT(_x) ((_x) * SCALE_FACTOR) > +#define SCALE_MUL(_a, _b) (((_a)*(_b)) / SCALE_FACTOR) > +#define SCALE_DIV(_a, _b) (((_a)*SCALE_FACTOR)/(_b)) > +#define SCALE_TO_MCELSIUS(_x) ((_x) * 10) Spaces around operators everywhere, please. I wonder about SCALE_MUL; isn't that more like "unscaling" because _a and _b are already scaled? And since _b is always a constant, couldn't we simply drop this macro and simply do _a * _b (with _a being scaled already and _b not)? Regards, Wolfram
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