SolarLader/LNSC-2420-Firmware
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Fixed temperature measurement

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This commit is contained in:
Thomas Kolb 2021-06-12 16:47:59 +02:00
parent df3211333e
commit add925bba0
1 changed files with 12 additions and 9 deletions
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21
src/measurement.c
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@ -17,20 +17,23 @@ static fxp_t calibration_factors[ADC_NUM_CHANNELS-1]; // all except temperature;
/* Temperature sensor calibration value address */
#define TEMP110_CAL_ADDR ((uint16_t*) ((uint32_t) 0x1FFFF7C2))
#define TEMP30_CAL_ADDR ((uint16_t*) ((uint32_t) 0x1FFFF7B8))
#define VDD_CALIB ((uint16_t) (330)) /* calibration voltage = 3,30V - DO NOT CHANGE */
#define VDD_APPLI ((uint16_t) (330)) /* actual supply voltage */
#define VDD_CALIB ((int32_t) (330)) /* calibration voltage = 3,30V - DO NOT CHANGE */
#define VDD_APPLI ((int32_t) (330)) /* actual supply voltage */
/* function for temperature conversion */
static fxp_t calc_temperature(uint16_t adc_val)
{
fxp_t temperature = FXP_FROM_INT(
((int32_t)adc_val * VDD_APPLI / VDD_CALIB) -
(int32_t)*TEMP30_CAL_ADDR);
int32_t temperature_raw = ((int32_t)adc_val * VDD_APPLI / VDD_CALIB)
- (int32_t)(*TEMP30_CAL_ADDR);
temperature = fxp_mult(temperature, FXP_FROM_INT(110 - 30));
temperature = fxp_div(temperature, FXP_FROM_INT(*TEMP110_CAL_ADDR - *TEMP30_CAL_ADDR));
fxp_t temperature = FXP_FROM_INT(temperature_raw);
return fxp_add(temperature, FXP_FROM_INT(30));
fxp_t scale_dividend = FXP_FROM_INT(110 - 30);
fxp_t scale_divisor = FXP_FROM_INT((int32_t)(*TEMP110_CAL_ADDR - *TEMP30_CAL_ADDR));
fxp_t scale = fxp_div(scale_dividend, scale_divisor);
return fxp_add(fxp_mult(temperature, scale), FXP_FROM_INT(30));
}
@ -71,7 +74,7 @@ void measurement_init(void)
ANALOG_INPUT_U_SW, // U_SW
ANALOG_INPUT_I_SOLAR, // I_Solar
ANALOG_INPUT_I_LOAD, // I_Load
16 // Temperature sensor
ADC_CHANNEL_TEMP // Temperature sensor
};
// Convert calibration factors to fixed-point numbers for direct use