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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"
/** \file hardware/adc.h
* \defgroup hardware_adc hardware_adc
*
* \brief Analog to Digital Converter (ADC) API
*
* RP-series microcontrollers have
* an internal analogue-digital converter (ADC) with the following features:
* - SAR ADC
* - 500 kS/s (Using an independent 48MHz clock)
* - 12 bit (RP2040 8.7 ENOB, RP2350 9.2 ENOB)
* \if rp2040_specific
* - RP2040 5 input mux:
* - 4 inputs that are available on package pins shared with GPIO[29:26]
* - 1 input is dedicated to the internal temperature sensor
* - 4 element receive sample FIFO
* \endif
*
* \if rp2350_specific
* - RP2350 5 or 9 input mux:
* - 4 inputs available on QFN-60 package pins shared with GPIO[29:26]
* - 8 inputs available on QFN-80 package pins shared with GPIO[47:40]
* - 8 element receive sample FIFO
* \endif
* - One input dedicated to the internal temperature sensor (see Section 12.4.6)
* - Interrupt generation
* - DMA interface
*
* Although there is only one ADC you can specify the input to it using the adc_select_input() function.
* In round robin mode (adc_set_round_robin()), the ADC will use that input and move to the next one after a read.
*
* RP2040, RP2350 QFN-60: User ADC inputs are on 0-3 (GPIO 26-29), the temperature sensor is on input 4.
* RP2350 QFN-80 : User ADC inputs are on 0-7 (GPIO 40-47), the temperature sensor is on input 8.
*
* Temperature sensor values can be approximated in centigrade as:
*
* T = 27 - (ADC_Voltage - 0.706)/0.001721
*
* \subsection adc_example Example
* \addtogroup hardware_adc
*
* \include hello_adc.c
*/
// 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
/**
* The ADC channel number of the on-board temperature sensor
*/
#ifndef ADC_TEMPERATURE_CHANNEL_NUM
#define ADC_TEMPERATURE_CHANNEL_NUM (NUM_ADC_CHANNELS - 1)
#endif
#ifdef __cplusplus
extern "C" {
#endif
/*! \brief Initialise the ADC HW
* \ingroup hardware_adc
*
*/
void adc_init(void);
/*! \brief Initialise the gpio for use as an ADC pin
* \ingroup hardware_adc
*
* Prepare a GPIO for use with ADC by disabling all digital functions.
*
* \param gpio The GPIO number to use. Allowable GPIO numbers are 26 to 29 inclusive on RP2040 or RP2350A, 40-48 inclusive on RP2350B
*/
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);
}
/*! \brief ADC input select
* \ingroup hardware_adc
*
* Select an ADC input
* \if rp2040_specific
* On RP02040 0...3 are GPIOs 26...29 respectively. Input 4 is the onboard temperature sensor.
* \endif
* \if rp2350_specific
* On RP2350A 0...3 are GPIOs 26...29 respectively. Input 4 is the onboard temperature sensor.
* On RP2350B 0...7 are GPIOs 40...47 respectively. Input 8 is the onboard temperature sensor.
* \endif
*
* \param input Input to select.
*/
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);
}
/*! \brief Get the currently selected ADC input channel
* \ingroup hardware_adc
*
* \return The currently selected input channel.
*
* \if rp2040_specific
* On RP02040 0...3 are GPIOs 26...29 respectively. Input 4 is the onboard temperature sensor.
* \endif
*
* \if rp2350_specific
* On RP2350A 0...3 are GPIOs 26...29 respectively. Input 4 is the onboard temperature sensor.
* On RP2350B 0...7 are GPIOs 40...47 respectively. Input 8 is the onboard temperature sensor.
* \endif
*/
static inline uint adc_get_selected_input(void) {
return (adc_hw->cs & ADC_CS_AINSEL_BITS) >> ADC_CS_AINSEL_LSB;
}
/*! \brief Round Robin sampling selector
* \ingroup hardware_adc
*
* This function sets which inputs are to be run through in round robin mode.
* RP2040, RP2350 QFN-60: Value between 0 and 0x1f (bit 0 to bit 4 for GPIO 26 to 29 and temperature sensor input respectively)
* RP2350 QFN-80: Value between 0 and 0xff (bit 0 to bit 7 for GPIO 40 to 47 and temperature sensor input respectively)
*
* \param input_mask A bit pattern indicating which of the 5/8 inputs are to be sampled. Write a value of 0 to disable round robin sampling.
*/
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);
}
/*! \brief Enable the onboard temperature sensor
* \ingroup hardware_adc
*
* \param enable Set true to power on the onboard temperature sensor, false to power off.
*
*/
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);
}
/*! \brief Perform a single conversion
* \ingroup hardware_adc
*
* Performs an ADC conversion, waits for the result, and then returns it.
*
* \return Result of the conversion.
*/
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;
}
/*! \brief Enable or disable free-running sampling mode
* \ingroup hardware_adc
*
* \param run false to disable, true to enable free running conversion mode.
*/
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);
}
/*! \brief Set the ADC Clock divisor
* \ingroup hardware_adc
*
* Period of samples will be (1 + div) cycles on average. Note it takes 96 cycles to perform a conversion,
* so any period less than that will be clamped to 96.
*
* \param clkdiv If non-zero, conversion will be started at intervals rather than back to back.
*/
static inline void adc_set_clkdiv(float clkdiv) {
invalid_params_if(HARDWARE_ADC, clkdiv >= 1 << (ADC_DIV_INT_MSB - ADC_DIV_INT_LSB + 1));
adc_hw->div = (uint32_t)(clkdiv * (float) (1 << ADC_DIV_INT_LSB));
}
/*! \brief Setup the ADC FIFO
* \ingroup hardware_adc
*
* \if rp2040_specific
* On RP2040 the FIFO is 4 samples long.
* \endif
*
* \if rp2350_specific
* On RP2350 the FIFO is 8 samples long.
* \endif
*
* If a conversion is completed and the FIFO is full, the result is dropped.
*
* \param en Enables write each conversion result to the FIFO
* \param dreq_en Enable DMA requests when FIFO contains data
* \param dreq_thresh Threshold for DMA requests/FIFO IRQ if enabled.
* \param err_in_fifo If enabled, bit 15 of the FIFO contains error flag for each sample
* \param byte_shift Shift FIFO contents to be one byte in size (for byte DMA) - enables DMA to byte buffers.
*/
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
);
}
/*! \brief Check FIFO empty state
* \ingroup hardware_adc
*
* \return Returns true if the FIFO is empty
*/
static inline bool adc_fifo_is_empty(void) {
return adc_hw->fcs & ADC_FCS_EMPTY_BITS;
}
/*! \brief Get number of entries in the ADC FIFO
* \ingroup hardware_adc
*
* \if rp2040_specific
* On RP2040 the FIFO is 4 samples long.
* \endif
* \if rp2350_specific
* On RP2350 the FIFO is 8 samples long.
* \endif
*
* This function will return how many samples are currently present.
*/
static inline uint8_t adc_fifo_get_level(void) {
return (adc_hw->fcs & ADC_FCS_LEVEL_BITS) >> ADC_FCS_LEVEL_LSB;
}
/*! \brief Get ADC result from FIFO
* \ingroup hardware_adc
*
* Pops the latest result from the ADC FIFO.
*/
static inline uint16_t adc_fifo_get(void) {
return (uint16_t)adc_hw->fifo;
}
/*! \brief Wait for the ADC FIFO to have data.
* \ingroup hardware_adc
*
* Blocks until data is present in the FIFO
*/
static inline uint16_t adc_fifo_get_blocking(void) {
while (adc_fifo_is_empty())
tight_loop_contents();
return (uint16_t)adc_hw->fifo;
}
/*! \brief Drain the ADC FIFO
* \ingroup hardware_adc
*
* Will wait for any conversion to complete then drain the FIFO, discarding any results.
*/
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();
}
/*! \brief Enable/Disable ADC interrupts.
* \ingroup hardware_adc
*
* \param enabled Set to true to enable the ADC interrupts, false to disable
*/
static inline void adc_irq_set_enabled(bool enabled) {
adc_hw->inte = !!enabled;
}
#ifdef __cplusplus
}
#endif
#endif
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