arduino-esp32/cores/esp32/esp32-hal-adc.c

// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "esp32-hal-adc.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_attr.h"
#include "soc/rtc_cntl_reg.h"
#include "driver/adc.h"

#include "esp_system.h"
#ifdef ESP_IDF_VERSION_MAJOR // IDF 4+
#if CONFIG_IDF_TARGET_ESP32 // ESP32/PICO-D4
#include "esp_adc_cal.h"
#include "soc/sens_reg.h"
#include "soc/rtc_io_reg.h"
#include "esp32/rom/ets_sys.h"
#include "esp_intr_alloc.h"
#define DEFAULT_VREF    1100
static esp_adc_cal_characteristics_t *__analogCharacteristics[2] = {NULL, NULL};
static uint16_t __analogVRef = 0;
static uint8_t __analogVRefPin = 0;
#elif CONFIG_IDF_TARGET_ESP32S2
#include "esp32s2/rom/ets_sys.h"
#include "soc/sens_reg.h"
#include "soc/rtc_io_reg.h"
#elif CONFIG_IDF_TARGET_ESP32C3
#include "esp32c3/rom/ets_sys.h"
#else 
#error Target CONFIG_IDF_TARGET is not supported
#endif
#else // ESP32 Before IDF 4.0
#include "rom/ets_sys.h"
#include "esp_intr.h"
#endif

static uint8_t __analogAttenuation = 3;//11db
static uint8_t __analogWidth = 3;//12 bits
static uint8_t __analogClockDiv = 1;
static adc_attenuation_t __pin_attenuation[SOC_GPIO_PIN_COUNT];

void __analogSetClockDiv(uint8_t clockDiv){
    if(!clockDiv){
        clockDiv = 1;
    }
    __analogClockDiv = clockDiv;
#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2
    adc_set_clk_div(__analogClockDiv);
#endif
}

void __analogSetAttenuation(adc_attenuation_t attenuation)
{
    __analogAttenuation = attenuation & 3;
}

#if CONFIG_IDF_TARGET_ESP32
void __analogSetWidth(uint8_t bits){
    if(bits < 9){
        bits = 9;
    } else if(bits > 12){
        bits = 12;
    }
    __analogWidth = bits - 9;
    adc1_config_width(__analogWidth);
}
#endif

void __analogInit(){
    static bool initialized = false;
    if(initialized){
        return;
    }
    initialized = true;
    __analogSetClockDiv(__analogClockDiv);
#if CONFIG_IDF_TARGET_ESP32
    __analogSetWidth(__analogWidth + 9);//in bits
#endif
    for(int i=0; i<SOC_GPIO_PIN_COUNT; i++){
        __pin_attenuation[i] = ADC_ATTENDB_MAX;
    }
}

void __analogSetPinAttenuation(uint8_t pin, adc_attenuation_t attenuation)
{
    int8_t channel = digitalPinToAnalogChannel(pin);
    if(channel < 0 || attenuation > 3){
        return ;
    }
    if(channel > 9){
        adc2_config_channel_atten(channel - 10, attenuation);
    } else {
        adc1_config_channel_atten(channel, attenuation);
    }
    __analogInit();
    if((__pin_attenuation[pin] != ADC_ATTENDB_MAX) || (attenuation != __analogAttenuation)){
        __pin_attenuation[pin] = attenuation;
    }
}

bool __adcAttachPin(uint8_t pin){
    int8_t channel = digitalPinToAnalogChannel(pin);
    if(channel < 0){
        log_e("Pin %u is not ADC pin!", pin);
        return false;
    }
    __analogInit();
    int8_t pad = digitalPinToTouchChannel(pin);
    if(pad >= 0){
#if CONFIG_IDF_TARGET_ESP32
        uint32_t touch = READ_PERI_REG(SENS_SAR_TOUCH_ENABLE_REG);
        if(touch & (1 << pad)){
            touch &= ~((1 << (pad + SENS_TOUCH_PAD_OUTEN2_S))
                    | (1 << (pad + SENS_TOUCH_PAD_OUTEN1_S))
                    | (1 << (pad + SENS_TOUCH_PAD_WORKEN_S)));
            WRITE_PERI_REG(SENS_SAR_TOUCH_ENABLE_REG, touch);
        }
#endif
    }
#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2
    else if(pin == 25){
        CLEAR_PERI_REG_MASK(RTC_IO_PAD_DAC1_REG, RTC_IO_PDAC1_XPD_DAC | RTC_IO_PDAC1_DAC_XPD_FORCE);//stop dac1
    } else if(pin == 26){
        CLEAR_PERI_REG_MASK(RTC_IO_PAD_DAC2_REG, RTC_IO_PDAC2_XPD_DAC | RTC_IO_PDAC2_DAC_XPD_FORCE);//stop dac2
    }
#endif

    pinMode(pin, ANALOG);
    __analogSetPinAttenuation(pin, (__pin_attenuation[pin] != ADC_ATTENDB_MAX)?__pin_attenuation[pin]:__analogAttenuation);
    return true;
}

void __analogReadResolution(uint8_t bits)
{
    if(!bits || bits > 16){
        return;
    }
#if CONFIG_IDF_TARGET_ESP32
    __analogSetWidth(bits);         // hadware from 9 to 12
#endif
}

uint16_t __analogRead(uint8_t pin)
{
    int8_t channel = digitalPinToAnalogChannel(pin);
    int value = 0;
    esp_err_t r = ESP_OK;
    if(channel < 0){
        log_e("Pin %u is not ADC pin!", pin);
        return value;
    }
    __adcAttachPin(pin);
    if(channel > 9){
        channel -= 10;
        r = adc2_get_raw( channel, __analogWidth, &value);
        if ( r == ESP_OK ) {
            return value;
        } else if ( r == ESP_ERR_INVALID_STATE ) {
            log_e("GPIO%u: %s: ADC2 not initialized yet.", pin, esp_err_to_name(r));
        } else if ( r == ESP_ERR_TIMEOUT ) {
            log_e("GPIO%u: %s: ADC2 is in use by Wi-Fi. Please see https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/adc.html#adc-limitations for more info", pin, esp_err_to_name(r));
        } else {
            log_e("GPIO%u: %s", pin, esp_err_to_name(r));
        }
    } else {
        return adc1_get_raw(channel);
    }
    return value;
}

uint32_t __analogReadMilliVolts(uint8_t pin){
    int8_t channel = digitalPinToAnalogChannel(pin);
    if(channel < 0){
        log_e("Pin %u is not ADC pin!", pin);
        return 0;
    }
#if CONFIG_IDF_TARGET_ESP32
    if(!__analogVRef){
        if (esp_adc_cal_check_efuse(ESP_ADC_CAL_VAL_EFUSE_TP) == ESP_OK) {
            log_d("eFuse Two Point: Supported");
            __analogVRef = DEFAULT_VREF;
        }