mirror of
https://github.com/mytechnotalent/Embedded-Hacking.git
synced 2026-05-22 15:39:39 +02:00
Kevin Thomas
c46bcba401
Public function docstrings belong exclusively in .h headers per coding convention. Only static helper functions and static variables retain docstrings in .c files. Removed 413 duplicate docstrings across 185 files (15 CBM + 15 C SDK projects). All 30 projects rebuild with zero errors.
86 lines
2.7 KiB
C
86 lines
2.7 KiB
C
/**
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* @file adc.c
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* @brief Implementation of the 12-bit ADC driver
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* @author Kevin Thomas
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* @date 2025
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*
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* MIT License
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*
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* Copyright (c) 2025 Kevin Thomas
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "adc.h"
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#include "pico/stdlib.h"
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#include "hardware/adc.h"
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/** @brief ADC reference voltage in millivolts */
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#define ADC_VREF_MV 3300
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/** @brief Maximum 12-bit ADC raw value */
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#define ADC_FULL_SCALE 4095
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/** @brief Currently selected ADC input channel */
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static uint8_t active_channel = 0;
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/**
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* @brief Convert a raw 12-bit ADC value to millivolts
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*
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* Scales the raw value linearly against the 3.3 V reference.
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*
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* @param raw 12-bit ADC conversion result (0 - 4095)
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* @return uint32_t Equivalent voltage in millivolts (0 - 3300)
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*/
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static uint32_t _raw_to_mv(uint16_t raw) {
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return (uint32_t)raw * ADC_VREF_MV / ADC_FULL_SCALE;
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}
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/**
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* @brief Convert a raw temperature-sensor ADC value to degrees Celsius
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*
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* Applies the RP2350 datasheet formula:
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* T = 27 - (V - 0.706) / 0.001721
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*
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* @param raw 12-bit ADC result from the internal temperature sensor (channel 4)
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* @return float Die temperature in degrees Celsius
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*/
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static float _raw_to_celsius(uint16_t raw) {
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float voltage = (float)raw * 3.3f / (float)ADC_FULL_SCALE;
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return 27.0f - (voltage - 0.706f) / 0.001721f;
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}
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void adc_driver_init(uint32_t gpio, uint8_t channel) {
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active_channel = channel;
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adc_init();
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adc_gpio_init(gpio);
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adc_set_temp_sensor_enabled(true);
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adc_select_input(channel);
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}
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uint32_t adc_driver_read_mv(void) {
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return _raw_to_mv(adc_read());
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}
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float adc_driver_read_temp_celsius(void) {
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adc_select_input(4);
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float result = _raw_to_celsius(adc_read());
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adc_select_input(active_channel);
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return result;
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}
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