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stm32/adc: Fix calibrated volt/temp readings on H7 by using 16bit scale.

This commit is contained in:
Damien George 2018-12-12 12:50:37 +11:00
parent 1b4031ed64
commit 0555ada277
1 changed files with 16 additions and 23 deletions
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39
ports/stm32/adc.c
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@ -67,6 +67,7 @@
#define ADC_CAL_ADDRESS (0x1ffff7ba)
#define ADC_CAL1 ((uint16_t*)0x1ffff7b8)
#define ADC_CAL2 ((uint16_t*)0x1ffff7c2)
#define ADC_CAL_BITS (12)
#elif defined(STM32F4)
@ -76,6 +77,7 @@
#define ADC_CAL_ADDRESS (0x1fff7a2a)
#define ADC_CAL1 ((uint16_t*)(ADC_CAL_ADDRESS + 2))
#define ADC_CAL2 ((uint16_t*)(ADC_CAL_ADDRESS + 4))
#define ADC_CAL_BITS (12)
#elif defined(STM32F7)
@ -91,6 +93,7 @@
#define ADC_CAL1 ((uint16_t*)(ADC_CAL_ADDRESS + 2))
#define ADC_CAL2 ((uint16_t*)(ADC_CAL_ADDRESS + 4))
#define ADC_CAL_BITS (12)
#elif defined(STM32H7)
@ -100,6 +103,7 @@
#define ADC_CAL_ADDRESS (0x1FF1E860)
#define ADC_CAL1 ((uint16_t*)(0x1FF1E820))
#define ADC_CAL2 ((uint16_t*)(0x1FF1E840))
#define ADC_CAL_BITS (16)
#define ADC_CHANNEL_VBAT ADC_CHANNEL_VBAT_DIV4
#elif defined(STM32L4)
@ -110,6 +114,7 @@
#define ADC_CAL_ADDRESS (0x1fff75aa)
#define ADC_CAL1 ((uint16_t*)(ADC_CAL_ADDRESS - 2))
#define ADC_CAL2 ((uint16_t*)(ADC_CAL_ADDRESS + 0x20))
#define ADC_CAL_BITS (12)
#else
@ -149,7 +154,7 @@
#define CORE_TEMP_AVG_SLOPE (3) /* (2.5mv/3.3v)*(2^ADC resoultion) */
// scale and calibration values for VBAT and VREF
#define ADC_SCALE (ADC_SCALE_V / 4095)
#define ADC_SCALE (ADC_SCALE_V / ((1 << ADC_CAL_BITS) - 1))
#define VREFIN_CAL ((uint16_t *)ADC_CAL_ADDRESS)
typedef struct _pyb_obj_adc_t {
@ -699,13 +704,14 @@ int adc_get_resolution(ADC_HandleTypeDef *adcHandle) {
return 12;
}
STATIC uint32_t adc_config_and_read_ref(ADC_HandleTypeDef *adcHandle, uint32_t channel) {
uint32_t raw_value = adc_config_and_read_channel(adcHandle, channel);
// Scale raw reading to the number of bits used by the calibration constants
return raw_value << (ADC_CAL_BITS - adc_get_resolution(adcHandle));
}
int adc_read_core_temp(ADC_HandleTypeDef *adcHandle) {
int32_t raw_value = adc_config_and_read_channel(adcHandle, ADC_CHANNEL_TEMPSENSOR);
// Note: constants assume 12-bit resolution, so we scale the raw value to
// be 12-bits.
raw_value <<= (12 - adc_get_resolution(adcHandle));
int32_t raw_value = adc_config_and_read_ref(adcHandle, ADC_CHANNEL_TEMPSENSOR);
return ((raw_value - CORE_TEMP_V25) / CORE_TEMP_AVG_SLOPE) + 25;
}
@ -714,31 +720,18 @@ int adc_read_core_temp(ADC_HandleTypeDef *adcHandle) {
STATIC volatile float adc_refcor = 1.0f;
float adc_read_core_temp_float(ADC_HandleTypeDef *adcHandle) {
int32_t raw_value = adc_config_and_read_channel(adcHandle, ADC_CHANNEL_TEMPSENSOR);
// constants assume 12-bit resolution so we scale the raw value to 12-bits
raw_value <<= (12 - adc_get_resolution(adcHandle));
int32_t raw_value = adc_config_and_read_ref(adcHandle, ADC_CHANNEL_TEMPSENSOR);
float core_temp_avg_slope = (*ADC_CAL2 - *ADC_CAL1) / 80.0;
return (((float)raw_value * adc_refcor - *ADC_CAL1) / core_temp_avg_slope) + 30.0f;
}
float adc_read_core_vbat(ADC_HandleTypeDef *adcHandle) {
uint32_t raw_value = adc_config_and_read_channel(adcHandle, ADC_CHANNEL_VBAT);
// Note: constants assume 12-bit resolution, so we scale the raw value to
// be 12-bits.
raw_value <<= (12 - adc_get_resolution(adcHandle));
uint32_t raw_value = adc_config_and_read_ref(adcHandle, ADC_CHANNEL_VBAT);
return raw_value * VBAT_DIV * ADC_SCALE * adc_refcor;
}
float adc_read_core_vref(ADC_HandleTypeDef *adcHandle) {
uint32_t raw_value = adc_config_and_read_channel(adcHandle, ADC_CHANNEL_VREFINT);
// Note: constants assume 12-bit resolution, so we scale the raw value to
// be 12-bits.
raw_value <<= (12 - adc_get_resolution(adcHandle));
uint32_t raw_value = adc_config_and_read_ref(adcHandle, ADC_CHANNEL_VREFINT);
// update the reference correction factor
adc_refcor = ((float)(*VREFIN_CAL)) / ((float)raw_value);