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docs: Update full-scale voltages for ESP32-S2 chip

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Krzysztof 2020-12-28 11:54:51 +08:00
parent 10f16c5d72
commit 250805d991
1 changed files with 69 additions and 65 deletions
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90
components/driver/include/driver/adc_common.h
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@ -128,44 +128,34 @@ esp_err_t adc1_pad_get_io_num(adc1_channel_t channel, gpio_num_t *gpio_num);
/** /**
* @brief Set the attenuation of a particular channel on ADC1, and configure its associated GPIO pin mux. * @brief Set the attenuation of a particular channel on ADC1, and configure its associated GPIO pin mux.
* *
* The default ADC full-scale voltage is 1.1 V. To read higher voltages (up to the pin maximum voltage, * The default ADC voltage is for attenuation 0 dB and listed in the table below.
* usually 3.3 V) requires setting >0 dB signal attenuation for that ADC channel. * By setting higher attenuation it is possible to read higher voltages.
* *
* When the analog voltage supply (VDDA) is 3.3 V: * Due to ADC characteristics, most accurate results are obtained within the "suggested range"
* shown in the following table.
* *
* - 0 dB attenuation (ADC_ATTEN_DB_0) gives full-scale voltage 1.1 V * +----------+-------------+-----------------+
* - 2.5 dB attenuation (ADC_ATTEN_DB_2_5) gives full-scale voltage 1.5 V * | | attenuation | suggested range |
* - 6 dB attenuation (ADC_ATTEN_DB_6) gives full-scale voltage 2.2 V * | SoC | (dB) | (mV) |
* - 11 dB attenuation (ADC_ATTEN_DB_11) gives full-scale voltage 3.9 V (see note below) * +==========+=============+=================+
*
* Due to ADC characteristics, most accurate results are obtained within the following approximate voltage ranges:
*
* +----------+------------+--------------------------+
* | SoC | attenuation| suggested range (mV) |
* +==========+============+==========================+
* | | 0 | 100 ~ 950 | * | | 0 | 100 ~ 950 |
* | +------------+--------------------------+ * | +-------------+-----------------+
* | | 2.5 | 100 ~ 1250 | * | | 2.5 | 100 ~ 1250 |
* | ESP32 +------------+--------------------------+ * | ESP32 +-------------+-----------------+
* | | 6 | 150 ~ 1750 | * | | 6 | 150 ~ 1750 |
* | +------------+--------------------------+ * | +-------------+-----------------+
* | | 11 | 150 ~ 2450 | * | | 11 | 150 ~ 2450 |
* +----------+------------+--------------------------+ * +----------+-------------+-----------------+
* | | 0 | 100 ~ 800 | * | | 0 | 0 ~ 750 |
* | +------------+--------------------------+ * | +-------------+-----------------+
* | | 2.5 | 100 ~ 1100 | * | | 2.5 | 0 ~ 1050 |
* | ESP32-S2 +------------+--------------------------+ * | ESP32-S2 +-------------+-----------------+
* | | 6 | 150 ~ 1350 | * | | 6 | 0 ~ 1300 |
* | +------------+--------------------------+ * | +-------------+-----------------+
* | | 11 | 150 ~ 2600 | * | | 11 | 0 ~ 2500 |
* +----------+------------+--------------------------+ * +----------+-------------+-----------------+
* *
* For maximum accuracy, use the ADC calibration APIs and measure voltages within these recommended ranges. * For maximum accuracy, use the ADC calibration APIs and measure voltages within these recommended ranges.
* @note The full-scale voltage is the voltage corresponding to a maximum reading (depending on ADC1 configured bit width,
* this value in ESP32 is 4095 for 12-bits, 2047 for 11-bits, 1023 for 10-bits, 511 for 9 bits.
* this value in ESP32-S2 is 8191 for 13-bits.)
*
* @note At 11 dB attenuation the maximum voltage is limited by VDDA, not the full scale voltage.
* *
* @note For any given channel, this function must be called before the first time ``adc1_get_raw()`` is called for that channel. * @note For any given channel, this function must be called before the first time ``adc1_get_raw()`` is called for that channel.
* *
@ -274,26 +264,40 @@ esp_err_t adc2_pad_get_io_num(adc2_channel_t channel, gpio_num_t *gpio_num);
/** /**
* @brief Configure the ADC2 channel, including setting attenuation. * @brief Configure the ADC2 channel, including setting attenuation.
* *
* The default ADC full-scale voltage is 1.1 V. To read higher voltages (up to the pin maximum voltage, * The default ADC voltage is for attenuation 0 dB and listed in the table below.
* usually 3.3 V) requires setting >0 dB signal attenuation for that ADC channel. * By setting higher attenuation it is possible to read higher voltages.
* *
* When the analog voltage supply (VDDA) is 3.3 V: * Due to ADC characteristics, most accurate results are obtained within the "suggested range"
* shown in the following table.
* *
* - 0 dB attenuation (ADC_ATTEN_0db) gives full-scale voltage 1.1 V * +----------+-------------+-----------------+
* - 2.5 dB attenuation (ADC_ATTEN_2_5db) gives full-scale voltage 1.5 V * | | attenuation | suggested range |
* - 6 dB attenuation (ADC_ATTEN_6db) gives full-scale voltage 2.2 V * | SoC | (dB) | (mV) |
* - 11 dB attenuation (ADC_ATTEN_11db) gives full-scale voltage 3.9 V (see note below) * +==========+=============+=================+
* | | 0 | 100 ~ 950 |
* | +-------------+-----------------+
* | | 2.5 | 100 ~ 1250 |
* | ESP32 +-------------+-----------------+
* | | 6 | 150 ~ 1750 |
* | +-------------+-----------------+
* | | 11 | 150 ~ 2450 |
* +----------+-------------+-----------------+
* | | 0 | 0 ~ 750 |
* | +-------------+-----------------+
* | | 2.5 | 0 ~ 1050 |
* | ESP32-S2 +-------------+-----------------+
* | | 6 | 0 ~ 1300 |
* | +-------------+-----------------+
* | | 11 | 0 ~ 2500 |
* +----------+-------------+-----------------+
*
* For maximum accuracy, use the ADC calibration APIs and measure voltages within these recommended ranges.
* *
* @note This function also configures the input GPIO pin mux to * @note This function also configures the input GPIO pin mux to
* connect it to the ADC2 channel. It must be called before calling * connect it to the ADC2 channel. It must be called before calling
* ``adc2_get_raw()`` for this channel. * ``adc2_get_raw()`` for this channel.
* *
* @note The full-scale voltage is the voltage corresponding to a maximum reading * @note For any given channel, this function must be called before the first time ``adc2_get_raw()`` is called for that channel.
* (depending on ADC2 configured bit width,
* this value for ESP32 is: 4095 for 12-bits, 2047 for 11-bits, 1023 for 10-bits, 511 for 9 bits.
* this value for ESP32-S2 is: 8191 for 13-bits.)
*
* @note At 11 dB attenuation the maximum voltage is limited by VDDA, not the full scale voltage.
* *
* @param channel ADC2 channel to configure * @param channel ADC2 channel to configure
* @param atten Attenuation level * @param atten Attenuation level