useful_macros.h

 
// This is a guard condition so that contents of this file are not included
// more than once.  
#ifndef USEFUL_MACROS_H
#define USEFUL_MACROS_H
 
#include <xc.h> // include processor files - each processor file is guarded.  
 
 
#define _rnd(a)    ((int16_t)((a)+((a)<0?-0.5:0.5)))
#define _min(a,b)  (((a)>(b)) ? (b):(a))
#define _max(a,b)  (((a)>(b)) ? (a):(b))
 
#define _rnd_int32_t(a)    ((int32_t)((a)+((a)<0?-0.5:0.5)))
 
// following 2 macros used to get high byte and low byte of a word
#define WordLowByte(word)   ((uint8_t) (word & 0x00FF))
#define WordHighByte(word)  ((uint8_t) (word >> 8))
 
// to convert number to QFORMAT (positive) with max resolution, multiply by 2^QFORMAT_SHIFT
// this gives max possibly resolution with 15 bits available
#define QFORMAT_SHIFT(value)  ((value) < ((float)(1<<0)) ? (15) : \
                              ((value) < ((float)(1<<1)) ? (14) : \
                              ((value) < ((float)(1<<2)) ? (13) : \
                              ((value) < ((float)(1<<3)) ? (12) : \
                              ((value) < ((float)(1<<4)) ? (11) : \
                              ((value) < ((float)(1<<5)) ? (10) : \
                              ((value) < ((float)(1<<6)) ? (9) : \
                              ((value) < ((float)(1<<7)) ? (8) : \
                              ((value) < ((float)(1<<8)) ? (7) : \
                              ((value) < ((float)(1<<9)) ? (6) : \
                              ((value) < ((float)(1<<10)) ? (5) : \
                              ((value) < ((float)(1<<11)) ? (4) : \
                              ((value) < ((float)(1<<13)) ? (3) : \
                              ((value) < ((float)(1<<13)) ? (2) : \
                              ((value) < ((float)(1<<14)) ? (1) : (0))))))))))))))))
 
// TIME_TO_TICKS: convert time in seconds to counter ticks
#define TIME_TO_TICKS(time, tick_period)    (_rnd(time/tick_period))
 
// RMS_TO_PEAK: sqrt(2): rms to peak-peak is 2*sqrt(2), so rms to peak is sqrt(2)
#define RMS_TO_PEAK           (1.414213562)
 
// AVG_TO_RMS: PI / (2* sqrt(2)) = 1.11
#define AVG_TO_RMS            (1.11)
 
#define RMS_TO_AVG            (1.0/AVG_TO_RMS)
 
// convert frequency in Hz to integer setting that can be loaded into the PWMxPER register
// PWM_HR_EDGE_ALIGNED_PGxPER: high resolution, edge aligned mode
// assuming a PWM clock frequency of 4GHz
#define PWM_HR_EDGE_ALIGNED_PGxPER(freq_hz)     ((uint16_t)(_rnd_int32_t((8.0*500.0e+6)/(float)freq_hz)-8.0))
 
// convert duty cycle in percent to an integer that can be loaded into the PGxDC register
// duty_percent should be between 0 and 100
#define PWM_HR_EDGE_ALIGNED_PGxDC(PGxPER, duty_percent)      ((uint16_t)(_rnd_int32_t((PGxPER+8)*(duty_percent/100.0))))
 
// convert trigger offset in seconds to an integer that can be loaded into PGxTRIGy register
#define PWM_HR_PGxTRIGy(trigger_offset)        ((uint16_t)(_rnd_int32_t(8.0*500.0e+6*trigger_offset)))
 
// converter dead times in seconds to integer that can be loaded into PGxDTy register
#define PWM_HR_PGxDTy(dead_time)                ((uint16_t)(_rnd_int32_t(8.0*500.0e+6*dead_time)))
 
// convert a threshold in engineering units (volts,amps etc,) or amps to ADC threshold
// formula is:
// integer threshold = (volts or amps threshold)*gain + offset
#define UNITS_FROM_ENG_TO_ADC(threshold, gain, offset)       (_rnd((((float)threshold*(float)gain) + (float)offset)/3.3*4095.0))
 
#define UNITS_FROM_ADC_TO_ENG(AdcValue, Gain)       (_rnd((((float)AdcValue /(float)Gain))/4095.0 * 3.3))
 
 // end of group ~~~~~~~~~~~~~~~~~~~~
 
#endif  /* USEFUL_MACROS_H */