adc.h

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/*
 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
 
#ifndef _HARDWARE_ADC_H
#define _HARDWARE_ADC_H
 
#include "pico.h"
#include "hardware/structs/adc.h"
#include "hardware/gpio.h"

 
// PICO_CONFIG: PARAM_ASSERTIONS_ENABLED_HARDWARE_ADC, Enable/disable assertions in the hardware_adc module, type=bool, default=0, group=hardware_adc
#ifndef PARAM_ASSERTIONS_ENABLED_HARDWARE_ADC
#ifdef PARAM_ASSERTIONS_ENABLED_ADC // backwards compatibility with SDK < 2.0.0
#define PARAM_ASSERTIONS_ENABLED_HARDWARE_ADC PARAM_ASSERTIONS_ENABLED_ADC
#else
#define PARAM_ASSERTIONS_ENABLED_HARDWARE_ADC 0
#endif
#endif

#ifndef ADC_TEMPERATURE_CHANNEL_NUM
#define ADC_TEMPERATURE_CHANNEL_NUM (NUM_ADC_CHANNELS - 1)
#endif
 
// PICO_CONFIG: PICO_ADC_CLKDIV_ROUND_NEAREST, True if floating point ADC clock divisors should be rounded to the nearest possible clock divisor rather than rounding down, type=bool, default=PICO_CLKDIV_ROUND_NEAREST, group=hardware_adc
#ifndef PICO_ADC_CLKDIV_ROUND_NEAREST
#define PICO_ADC_CLKDIV_ROUND_NEAREST PICO_CLKDIV_ROUND_NEAREST
#endif
 
#ifdef __cplusplus
extern "C" {
#endif

void adc_init(void);

static inline void adc_gpio_init(uint gpio) {
    invalid_params_if(HARDWARE_ADC, gpio < ADC_BASE_PIN || gpio >= ADC_BASE_PIN + NUM_ADC_CHANNELS - 1);
    // Select NULL function to make output driver hi-Z
    gpio_set_function(gpio, GPIO_FUNC_NULL);
    // Also disable digital pulls and digital receiver
    gpio_disable_pulls(gpio);
    gpio_set_input_enabled(gpio, false);
}

static inline void adc_select_input(uint input) {
    valid_params_if(HARDWARE_ADC, input < NUM_ADC_CHANNELS);
    hw_write_masked(&adc_hw->cs, input << ADC_CS_AINSEL_LSB, ADC_CS_AINSEL_BITS);
}

static inline uint adc_get_selected_input(void) {
    return (adc_hw->cs & ADC_CS_AINSEL_BITS) >> ADC_CS_AINSEL_LSB;
}

static inline void adc_set_round_robin(uint input_mask) {
    valid_params_if(HARDWARE_ADC, input_mask < (1 << NUM_ADC_CHANNELS));
    hw_write_masked(&adc_hw->cs, input_mask << ADC_CS_RROBIN_LSB, ADC_CS_RROBIN_BITS);
}

static inline void adc_set_temp_sensor_enabled(bool enable) {
    if (enable)
        hw_set_bits(&adc_hw->cs, ADC_CS_TS_EN_BITS);
    else
        hw_clear_bits(&adc_hw->cs, ADC_CS_TS_EN_BITS);
}

static inline uint16_t adc_read(void) {
    hw_set_bits(&adc_hw->cs, ADC_CS_START_ONCE_BITS);
 
    while (!(adc_hw->cs & ADC_CS_READY_BITS))
        tight_loop_contents();
 
    return (uint16_t) adc_hw->result;
}

static inline void adc_run(bool run) {
    if (run)
        hw_set_bits(&adc_hw->cs, ADC_CS_START_MANY_BITS);
    else
        hw_clear_bits(&adc_hw->cs, ADC_CS_START_MANY_BITS);
}

static inline void adc_set_clkdiv(float clkdiv) {
    invalid_params_if(HARDWARE_ADC, clkdiv >= 1 << REG_FIELD_WIDTH(ADC_DIV_INT));
    const int frac_bit_count = REG_FIELD_WIDTH(ADC_DIV_FRAC);
#if PICO_ADC_CLKDIV_ROUND_NEAREST
    clkdiv += 0.5f / (1 << frac_bit_count); // round to the nearest fraction
#endif
    adc_hw->div = (uint32_t)(clkdiv * (float) (1 << frac_bit_count));
}

 static inline void adc_fifo_setup(bool en, bool dreq_en, uint16_t dreq_thresh, bool err_in_fifo, bool byte_shift) {
    hw_write_masked(&adc_hw->fcs,
                   (bool_to_bit(en) << ADC_FCS_EN_LSB) |
                   (bool_to_bit(dreq_en) << ADC_FCS_DREQ_EN_LSB) |
                   (((uint)dreq_thresh) << ADC_FCS_THRESH_LSB) |
                   (bool_to_bit(err_in_fifo) << ADC_FCS_ERR_LSB) |
                   (bool_to_bit(byte_shift) << ADC_FCS_SHIFT_LSB),
                   ADC_FCS_EN_BITS |
                   ADC_FCS_DREQ_EN_BITS |
                   ADC_FCS_THRESH_BITS |
                   ADC_FCS_ERR_BITS |
                   ADC_FCS_SHIFT_BITS
    );
}

static inline bool adc_fifo_is_empty(void) {
    return adc_hw->fcs & ADC_FCS_EMPTY_BITS;
}

static inline uint8_t adc_fifo_get_level(void) {
    return (adc_hw->fcs & ADC_FCS_LEVEL_BITS) >> ADC_FCS_LEVEL_LSB;
}

static inline uint16_t adc_fifo_get(void) {
    return (uint16_t)adc_hw->fifo;
}

static inline uint16_t adc_fifo_get_blocking(void) {
    while (adc_fifo_is_empty())
        tight_loop_contents();
    return (uint16_t)adc_hw->fifo;
}

static inline void adc_fifo_drain(void) {
    // Potentially there is still a conversion in progress -- wait for this to complete before draining
    while (!(adc_hw->cs & ADC_CS_READY_BITS))
        tight_loop_contents();
    while (!adc_fifo_is_empty())
        (void) adc_fifo_get();
}

static inline void adc_irq_set_enabled(bool enabled) {
    adc_hw->inte = !!enabled;
}
 
#ifdef __cplusplus
}
#endif
 
#endif