ADC Multi-sampling

locale/circuitpython.pot

@@ -4275,7 +4275,7 @@ msgstr ""
 msgid "usecols keyword must be specified"
 msgstr ""
 
-#: py/objint.c
+#: py/objint.c shared-bindings/analogio/AnalogIn.c
 #, c-format
 msgid "value must fit in %d byte(s)"
 msgstr ""

ports/atmel-samd/common-hal/analogio/AnalogIn.c

@@ -27,7 +27,7 @@
 #endif
 
 void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self,
-    const mcu_pin_obj_t *pin) {
+    const mcu_pin_obj_t *pin, uint16_t sample_size) {
     uint8_t adc_index;
     uint8_t adc_channel = 0xff;
     for (adc_index = 0; adc_index < NUM_ADC_PER_PIN; adc_index++) {
@@ -50,6 +50,7 @@ void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self,
     self->instance = adc_insts[adc_index];
     self->channel = adc_channel;
     self->pin = pin;
+    self->sample_size = sample_size;
 }
 
 bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
@@ -99,13 +100,29 @@ uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
 
     uint16_t value;
     adc_sync_read_channel(&adc, self->channel, ((uint8_t *)&value), 2);
-    adc_sync_read_channel(&adc, self->channel, ((uint8_t *)&value), 2);
+
+    uint32_t avg_value = 0;
+    for (int i = 0; i < self->sample_size; i++) {
+        adc_sync_read_channel(&adc, self->channel, ((uint8_t *)&value), 2);
+        avg_value += value;
+    }
 
     adc_sync_deinit(&adc);
+
+    avg_value /= self->sample_size;
+
     // Stretch 12-bit ADC reading to 16-bit range
-    return (value << 4) | (value >> 8);
+    return (avg_value << 4) | (avg_value >> 8);
 }
 
 float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self) {
     return 3.3f;
 }
+
+uint16_t common_hal_analogio_analogin_get_sample_size(analogio_analogin_obj_t *self) {
+    return self->sample_size;
+}
+
+void common_hal_analogio_analogin_set_sample_size(analogio_analogin_obj_t *self, uint16_t sample_size) {
+    self->sample_size = sample_size;
+}

ports/atmel-samd/common-hal/analogio/AnalogIn.h

@@ -15,6 +15,7 @@ typedef struct {
     const mcu_pin_obj_t *pin;
     Adc *instance;
     uint8_t channel;
+    uint8_t sample_size;
 } analogio_analogin_obj_t;
 
 void analogin_reset(void);

ports/cxd56/common-hal/analogio/AnalogIn.c

@@ -31,7 +31,7 @@ static analogin_dev_t analogin_dev[] = {
     {"/dev/hpadc1", &pin_HPADC1, -1},
 };
 
-void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self, const mcu_pin_obj_t *pin) {
+void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self, const mcu_pin_obj_t *pin, uint16_t sample_size) {
     if (!pin->analog) {
         raise_ValueError_invalid_pin();
     }
@@ -66,6 +66,7 @@ void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self, const
     ioctl(analogin_dev[self->number].fd, ANIOC_CXD56_START, 0);
 
     self->pin = pin;
+    self->sample_size = sample_size;
 }
 
 void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
@@ -86,11 +87,14 @@ bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
 }
 
 uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
-    int16_t value = 0;
-
-    read(analogin_dev[self->number].fd, &value, sizeof(value));
-
-    return (uint16_t)32768 + (uint16_t)value;
+    uint32_t avg_value = 0;
+    for (uint16_t i = 0; i < self->sample_size; i++) {
+        int16_t value = 0;
+        read(analogin_dev[self->number].fd, &value, sizeof(value));
+        avg_value += (uint16_t)32768 + (uint16_t)value;
+    }
+    avg_value /= self->sample_size;
+    return avg_value;
 }
 
 // Reference voltage is a fixed value which is depending on the board.
@@ -119,3 +123,11 @@ void analogin_reset(void) {
         }
     }
 }
+
+uint16_t common_hal_analogio_analogin_get_sample_size(analogio_analogin_obj_t *self) {
+    return self->sample_size;
+}
+
+void common_hal_analogio_analogin_set_sample_size(analogio_analogin_obj_t *self, uint16_t sample_size) {
+    self->sample_size = sample_size;
+}

ports/cxd56/common-hal/analogio/AnalogIn.h

@@ -14,6 +14,7 @@ typedef struct {
     mp_obj_base_t base;
     const mcu_pin_obj_t *pin;
     int8_t number;
+    uint16_t sample_size;
 } analogio_analogin_obj_t;
 
 void analogin_reset(void);

ports/espressif/common-hal/analogio/AnalogIn.c

@@ -22,7 +22,6 @@
 #include <string.h>
 
 #define DEFAULT_VREF        1100
-#define NO_OF_SAMPLES       2
 #define ATTENUATION         ADC_ATTEN_DB_11
 #if defined(CONFIG_IDF_TARGET_ESP32)
 #define DATA_WIDTH          ADC_BITWIDTH_12
@@ -43,7 +42,7 @@
 #endif
 
 void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self,
-    const mcu_pin_obj_t *pin) {
+    const mcu_pin_obj_t *pin, uint16_t sample_size) {
     if (pin->adc_index == NO_ADC || pin->adc_channel == NO_ADC_CHANNEL) {
         raise_ValueError_invalid_pin();
     }
@@ -53,104 +52,110 @@ void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self,
     // Turn off the pull-up as soon as we know the pin will be used for analog reads,
     // since it may take a while for the voltage to stabilize if the input is high-impedance.
     gpio_pullup_dis(pin->number);
-}
-
-bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
-    return self->pin == NULL;
-}
-
-void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
-    if (common_hal_analogio_analogin_deinited(self)) {
-        return;
-    }
-    reset_pin_number(self->pin->number);
-    self->pin = NULL;
-}
 
-uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
-    adc_oneshot_unit_handle_t adc_handle;
+    self->sample_size = sample_size;
     adc_oneshot_unit_init_cfg_t adc_config = {
         .unit_id = self->pin->adc_index,
         .ulp_mode = ADC_ULP_MODE_DISABLE
     };
-    CHECK_ESP_RESULT(adc_oneshot_new_unit(&adc_config, &adc_handle));
+    CHECK_ESP_RESULT(adc_oneshot_new_unit(&adc_config, &(self->adc_handle)));
 
     adc_oneshot_chan_cfg_t channel_config = {
         .atten = ATTENUATION,
         .bitwidth = DATA_WIDTH
     };
-    adc_channel_t channel = (adc_channel_t)self->pin->adc_channel;
-    adc_oneshot_config_channel(adc_handle, channel, &channel_config);
+    self->channel = (adc_channel_t)self->pin->adc_channel;
+    adc_oneshot_config_channel(self->adc_handle, self->channel, &channel_config);
 
     adc_cali_scheme_ver_t supported_schemes;
     adc_cali_check_scheme(&supported_schemes);
-    adc_cali_scheme_ver_t calibration_scheme = 0;
-    adc_cali_handle_t calibration;
+    self->calibration_scheme = 0;
 
     #if defined(ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED
-    adc_cali_curve_fitting_config_t config = {
-        .unit_id = self->pin->adc_index,
-        .chan = channel,
-        .atten = ATTENUATION,
-        .bitwidth = DATA_WIDTH
-    };
-    if (adc_cali_create_scheme_curve_fitting(&config, &calibration) == ESP_OK) {
-        calibration_scheme = ADC_CALI_SCHEME_VER_CURVE_FITTING;
+    self->config.unit_id = self->pin->adc_index;
+    self->config.chan = self->channel;
+    self->config.atten = ATTENUATION;
+    self->config.bitwidth = DATA_WIDTH;
+    if (adc_cali_create_scheme_curve_fitting(&(self->config), &(self->calibration)) == ESP_OK) {
+        self->calibration_scheme = ADC_CALI_SCHEME_VER_CURVE_FITTING;
     }
     #endif
     #if defined(ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED
-    if (calibration_scheme == 0) {
-        adc_cali_line_fitting_config_t config = {
-            .unit_id = self->pin->adc_index,
-            .atten = ATTENUATION,
-            .bitwidth = DATA_WIDTH,
-            #ifdef CONFIG_IDF_TARGET_ESP32
-            .default_vref = DEFAULT_VREF,
-            #endif
-        };
-        if (adc_cali_create_scheme_line_fitting(&config, &calibration) == ESP_OK) {
-            calibration_scheme = ADC_CALI_SCHEME_VER_LINE_FITTING;
-        }
+    if (self->calibration_scheme == 0) {
+        self->config.unit_id = self->pin->adc_index;
+        self->config.atten = ATTENUATION;
+        self->config.bitwidth = DATA_WIDTH;
+        #ifdef CONFIG_IDF_TARGET_ESP32
+        self->config.default_vref = DEFAULT_VREF;
+        #endif
+    }
+    ;
+    if (adc_cali_create_scheme_line_fitting(&(self->config), &(self->calibration)) == ESP_OK) {
+        self->calibration_scheme = ADC_CALI_SCHEME_VER_LINE_FITTING;
     }
     #endif
+}
+
+bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
+    return self->pin == NULL;
+}
 
+void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
+    if (common_hal_analogio_analogin_deinited(self)) {
+        return;
+    }
+    #if defined(ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED
+    if (self->calibration_scheme == ADC_CALI_SCHEME_VER_CURVE_FITTING) {
+        adc_cali_delete_scheme_curve_fitting(self->calibration);
+    }
+    #endif
+    #if defined(ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED
+    if (self->calibration_scheme == ADC_CALI_SCHEME_VER_LINE_FITTING) {
+        adc_cali_delete_scheme_line_fitting(self->calibration);
+    }
+    #endif
+    adc_oneshot_del_unit(self->adc_handle);
+    reset_pin_number(self->pin->number);
+    self->pin = NULL;
+}
+
+uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
     uint32_t adc_reading = 0;
-    size_t sample_count = 0;
+    uint16_t sample_count = 0;
+    uint8_t retries_left = 20;
     // Multisampling
     esp_err_t ret = ESP_OK;
-    for (int i = 0; i < NO_OF_SAMPLES; i++) {
+    while ((sample_count < self->sample_size) && retries_left) {
         int raw;
-        ret = adc_oneshot_read(adc_handle, channel, &raw);
+        ret = adc_oneshot_read(self->adc_handle, self->channel, &raw);
         if (ret != ESP_OK) {
-            continue;
+            retries_left--;
+        } else {
+            adc_reading += raw;
+            sample_count += 1;
         }
-        adc_reading += raw;
-        sample_count += 1;
     }
-    if (sample_count == 0) {
+    if (sample_count < self->sample_size) {
+        // 20 read failures, returns the final error
         raise_esp_error(ret);
     }
     adc_reading /= sample_count;
 
     // This corrects non-linear regions of the ADC range with a LUT, so it's a better reading than raw
     int voltage;
-    adc_cali_raw_to_voltage(calibration, adc_reading, &voltage);
-
+    adc_cali_raw_to_voltage(self->calibration, adc_reading, &voltage);
 
-    #if defined(ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED
-    if (calibration_scheme == ADC_CALI_SCHEME_VER_CURVE_FITTING) {
-        adc_cali_delete_scheme_curve_fitting(calibration);
-    }
-    #endif
-    #if defined(ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED
-    if (calibration_scheme == ADC_CALI_SCHEME_VER_LINE_FITTING) {
-        adc_cali_delete_scheme_line_fitting(calibration);
-    }
-    #endif
-    adc_oneshot_del_unit(adc_handle);
     return voltage * ((1 << 16) - 1) / 3300;
 }
 
 float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self) {
     return 3.3f;
 }
+
+uint16_t common_hal_analogio_analogin_get_sample_size(analogio_analogin_obj_t *self) {
+    return self->sample_size;
+}
+
+void common_hal_analogio_analogin_set_sample_size(analogio_analogin_obj_t *self, uint16_t sample_size) {
+    self->sample_size = sample_size;
+}

ports/espressif/common-hal/analogio/AnalogIn.h

@@ -12,8 +12,26 @@
 #include "FreeRTOS.h"
 #include "freertos/semphr.h"
 #include "py/obj.h"
+#include "adc_cali_schemes.h"
+#include "esp_adc/adc_oneshot.h"
+#include "esp_adc/adc_cali.h"
+#include "driver/gpio.h"
+#include "hal/adc_types.h"
+
 
 typedef struct {
     mp_obj_base_t base;
     const mcu_pin_obj_t *pin;
+    uint16_t sample_size;
+    adc_oneshot_unit_handle_t adc_handle;
+    adc_channel_t channel;
+    #if defined(ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED
+    adc_cali_curve_fitting_config_t config;
+    #endif
+    #if defined(ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED
+    adc_cali_line_fitting_config_t config;
+    #endif
+    adc_cali_scheme_ver_t calibration_scheme;
+    adc_cali_handle_t calibration;
+
 } analogio_analogin_obj_t;

ports/mimxrt10xx/common-hal/analogio/AnalogIn.c

@@ -18,7 +18,7 @@
 #define ADC_CHANNEL_GROUP 0
 
 void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self,
-    const mcu_pin_obj_t *pin) {
+    const mcu_pin_obj_t *pin, uint16_t sample_size) {
     adc_config_t config = {0};
 
     if (pin->adc == NULL) {
@@ -37,6 +37,7 @@ void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self,
     claim_pin(pin);
 
     self->pin = pin;
+    self->sample_size = sample_size;
 }
 
 bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
@@ -61,7 +62,11 @@ uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
 
     }
 
-    uint16_t value = ADC_GetChannelConversionValue(self->pin->adc, ADC_CHANNEL_GROUP);
+    uint32_t value = 0;
+    for (uint16_t i = 0; i < self->sample_size; i++) {
+        value += ADC_GetChannelConversionValue(self->pin->adc, ADC_CHANNEL_GROUP);
+    }
+    value /= self->sample_size;
 
     // Stretch 12-bit ADC reading to 16-bit range
     return (value << 4) | (value >> 8);
@@ -70,3 +75,11 @@ uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
 float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self) {
     return 3.3f;
 }
+
+uint16_t common_hal_analogio_analogin_get_sample_size(analogio_analogin_obj_t *self) {
+    return self->sample_size;
+}
+
+void common_hal_analogio_analogin_set_sample_size(analogio_analogin_obj_t *self, uint16_t sample_size) {
+    self->sample_size = sample_size;
+}

ports/mimxrt10xx/common-hal/analogio/AnalogIn.h

@@ -14,4 +14,5 @@
 typedef struct {
     mp_obj_base_t base;
     const mcu_pin_obj_t *pin;
+    uint16_t sample_size;
 } analogio_analogin_obj_t;