145 lines
4.8 KiB
C
145 lines
4.8 KiB
C
// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef _DRIVER_ADC_H_
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#define _DRIVER_ADC_H_
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <stdint.h>
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#include "esp_err.h"
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typedef enum {
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ADC_ATTEN_0db = 0, /*!<The input voltage of ADC will be reduced to about 1/1 */
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ADC_ATTEN_2_5db = 1, /*!<The input voltage of ADC will be reduced to about 1/1.34 */
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ADC_ATTEN_6db = 2, /*!<The input voltage of ADC will be reduced to about 1/2 */
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ADC_ATTEN_11db = 3, /*!<The input voltage of ADC will be reduced to about 1/3.6*/
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} adc_atten_t;
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typedef enum {
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ADC_WIDTH_9Bit = 0, /*!< ADC capture width is 9Bit*/
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ADC_WIDTH_10Bit = 1, /*!< ADC capture width is 10Bit*/
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ADC_WIDTH_11Bit = 2, /*!< ADC capture width is 11Bit*/
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ADC_WIDTH_12Bit = 3, /*!< ADC capture width is 12Bit*/
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} adc_bits_width_t;
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typedef enum {
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ADC1_CHANNEL_0 = 0, /*!< ADC1 channel 0 is GPIO36 */
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ADC1_CHANNEL_1, /*!< ADC1 channel 1 is GPIO37 */
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ADC1_CHANNEL_2, /*!< ADC1 channel 2 is GPIO38 */
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ADC1_CHANNEL_3, /*!< ADC1 channel 3 is GPIO39 */
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ADC1_CHANNEL_4, /*!< ADC1 channel 4 is GPIO32 */
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ADC1_CHANNEL_5, /*!< ADC1 channel 5 is GPIO33 */
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ADC1_CHANNEL_6, /*!< ADC1 channel 6 is GPIO34 */
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ADC1_CHANNEL_7, /*!< ADC1 channel 7 is GPIO35 */
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ADC1_CHANNEL_MAX,
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} adc1_channel_t;
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/**
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* @brief Configure ADC1 capture width.
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*
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* The configuration is for all channels of ADC1
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*
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* @param width_bit Bit capture width for ADC1
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*
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* @return
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* - ESP_OK success
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* - ESP_ERR_INVALID_ARG Parameter error
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*/
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esp_err_t adc1_config_width(adc_bits_width_t width_bit);
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/**
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* @brief Configure the ADC1 channel, including setting attenuation.
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*
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* @note This function also configures the input GPIO pin mux to
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* connect it to the ADC1 channel. It must be called before calling
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* adc1_get_voltage() for this channel.
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*
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* The default ADC full-scale voltage is 1.1V. To read higher voltages (up to the pin maximum voltage,
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* usually 3.3V) requires setting >0dB signal attenuation for that ADC channel.
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*
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* When VDD_A is 3.3V:
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*
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* - 0dB attenuaton (ADC_ATTEN_0db) gives full-scale voltage 1.1V
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* - 2.5dB attenuation (ADC_ATTEN_2_5db) gives full-scale voltage 1.5V
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* - 6dB attenuation (ADC_ATTEN_6db) gives full-scale voltage 2.2V
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* - 11dB attenuation (ADC_ATTEN_11db) gives full-scale voltage 3.9V (see note below)
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*
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* @note The full-scale voltage is the voltage corresponding to a maximum reading (depending on ADC1 configured
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* bit width, this value is: 4095 for 12-bits, 2047 for 11-bits, 1023 for 10-bits, 511 for 9 bits.)
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*
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* @note At 11dB attenuation the maximum voltage is limited by VDD_A, not the full scale voltage.
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*
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* @param channel ADC1 channel to configure
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* @param atten Attenuation level
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*
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* @return
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* - ESP_OK success
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* - ESP_ERR_INVALID_ARG Parameter error
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*/
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esp_err_t adc1_config_channel_atten(adc1_channel_t channel, adc_atten_t atten);
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/**
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* @brief Take an ADC1 reading on a single channel
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*
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* @note Call adc1_config_width() before the first time this
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* function is called.
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*
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* @note For a given channel, adc1_config_channel_atten(channel)
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* must be called before the first time this function is called.
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*
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* @param channel ADC1 channel to read
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*
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* @return
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* - -1: Parameter error
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* - Other: ADC1 channel reading.
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*/
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int adc1_get_voltage(adc1_channel_t channel);
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/**
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* @brief Configure ADC1 to be usable by the ULP
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*
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* This function reconfigures ADC1 to be controlled by the ULP.
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* Effect of this function can be reverted using adc1_get_voltage function.
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*
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* Note that adc1_config_channel_atten, adc1_config_width functions need
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* to be called to configure ADC1 channels, before ADC1 is used by the ULP.
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*/
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void adc1_ulp_enable();
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/**
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* @brief Read Hall Sensor
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*
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* @note The Hall Sensor uses channels 0 and 3 of ADC1. Do not configure
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* these channels for use as ADC channels.
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*
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* @note The ADC1 module must be enabled by calling
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* adc1_config_width() before calling hall_sensor_read(). ADC1
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* should be configured for 12 bit readings, as the hall sensor
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* readings are low values and do not cover the full range of the
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* ADC.
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*
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* @return The hall sensor reading.
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*/
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int hall_sensor_read();
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#ifdef __cplusplus
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}
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#endif
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#endif /*_DRIVER_ADC_H_*/
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