// 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_SIGMADELTA_H__
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#define __DRIVER_SIGMADELTA_H__
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#include <esp_types.h>
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#include "soc/gpio_sd_struct.h"
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#include "soc/gpio_sd_reg.h"
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#include "driver/gpio.h"
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#ifdef _cplusplus
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extern "C" {
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#endif
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/**
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* @brief Sigma-delta channel list
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*/
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typedef enum{
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SIGMADELTA_CHANNEL_0 = 0, /*!< Sigma-delta channel 0 */
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SIGMADELTA_CHANNEL_1 = 1, /*!< Sigma-delta channel 1 */
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SIGMADELTA_CHANNEL_2 = 2, /*!< Sigma-delta channel 2 */
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SIGMADELTA_CHANNEL_3 = 3, /*!< Sigma-delta channel 3 */
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SIGMADELTA_CHANNEL_4 = 4, /*!< Sigma-delta channel 4 */
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SIGMADELTA_CHANNEL_5 = 5, /*!< Sigma-delta channel 5 */
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SIGMADELTA_CHANNEL_6 = 6, /*!< Sigma-delta channel 6 */
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SIGMADELTA_CHANNEL_7 = 7, /*!< Sigma-delta channel 7 */
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SIGMADELTA_CHANNEL_MAX,
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} sigmadelta_channel_t;
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/**
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* @brief Sigma-delta configure struct
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*/
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typedef struct {
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sigmadelta_channel_t channel; /*!< Sigma-delta channel number */
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int8_t sigmadelta_duty; /*!< Sigma-delta duty, duty ranges from -128 to 127. */
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uint8_t sigmadelta_prescale; /*!< Sigma-delta prescale, prescale ranges from 0 to 255. */
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uint8_t sigmadelta_gpio; /*!< Sigma-delta output io number, refer to gpio.h for more details. */
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} sigmadelta_config_t;
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/**
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* @brief Configure Sigma-delta channel
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*
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* @param config Pointer of Sigma-delta channel configuration struct
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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 sigmadelta_config(const sigmadelta_config_t *config);
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/**
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* @brief Set Sigma-delta channel duty.
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*
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* This function is used to set Sigma-delta channel duty,
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* If you add a capacitor between the output pin and ground,
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* the average output voltage will be Vdc = VDDIO / 256 * duty + VDDIO/2,
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* where VDDIO is the power supply voltage.
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*
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* @param channel Sigma-delta channel number
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* @param duty Sigma-delta duty of one channel, the value ranges from -128 to 127, recommended range is -90 ~ 90.
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* The waveform is more like a random one in this range.
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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 sigmadelta_set_duty(sigmadelta_channel_t channel, int8_t duty);
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/**
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* @brief Set Sigma-delta channel's clock pre-scale value.
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* The source clock is APP_CLK, 80MHz. The clock frequency of the sigma-delta channel is APP_CLK / pre_scale
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*
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* @param channel Sigma-delta channel number
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* @param prescale The divider of source clock, ranges from 0 to 255
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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 sigmadelta_set_prescale(sigmadelta_channel_t channel, uint8_t prescale);
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/**
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* @brief Set Sigma-delta signal output pin
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*
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* @param channel Sigma-delta channel number
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* @param gpio_num GPIO number of output pin.
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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 sigmadelta_set_pin(sigmadelta_channel_t channel, gpio_num_t gpio_num);
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#ifdef _cplusplus
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}
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#endif
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#endif
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