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adc.h
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1/*
2 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7#ifndef _HARDWARE_ADC_H
8#define _HARDWARE_ADC_H
9
10#include "pico.h"
11#include "hardware/structs/adc.h"
12#include "hardware/gpio.h"
13
57// PICO_CONFIG: PARAM_ASSERTIONS_ENABLED_HARDWARE_ADC, Enable/disable assertions in the hardware_adc module, type=bool, default=0, group=hardware_adc
58#ifndef PARAM_ASSERTIONS_ENABLED_HARDWARE_ADC
59#ifdef PARAM_ASSERTIONS_ENABLED_ADC // backwards compatibility with SDK < 2.0.0
60#define PARAM_ASSERTIONS_ENABLED_HARDWARE_ADC PARAM_ASSERTIONS_ENABLED_ADC
61#else
62#define PARAM_ASSERTIONS_ENABLED_HARDWARE_ADC 0
63#endif
64#endif
65
69#ifndef ADC_TEMPERATURE_CHANNEL_NUM
70#define ADC_TEMPERATURE_CHANNEL_NUM (NUM_ADC_CHANNELS - 1)
71#endif
72
73// 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
74#ifndef PICO_ADC_CLKDIV_ROUND_NEAREST
75#define PICO_ADC_CLKDIV_ROUND_NEAREST PICO_CLKDIV_ROUND_NEAREST
76#endif
77
78#ifdef __cplusplus
79extern "C" {
80#endif
81
86void adc_init(void);
87
95static inline void adc_gpio_init(uint gpio) {
96 invalid_params_if(HARDWARE_ADC, gpio < ADC_BASE_PIN || gpio >= ADC_BASE_PIN + NUM_ADC_CHANNELS - 1);
97 // Select NULL function to make output driver hi-Z
99 // Also disable digital pulls and digital receiver
100 gpio_disable_pulls(gpio);
101 gpio_set_input_enabled(gpio, false);
102}
103
118static inline void adc_select_input(uint input) {
119 valid_params_if(HARDWARE_ADC, input < NUM_ADC_CHANNELS);
120 hw_write_masked(&adc_hw->cs, input << ADC_CS_AINSEL_LSB, ADC_CS_AINSEL_BITS);
121}
122
137static inline uint adc_get_selected_input(void) {
138 return (adc_hw->cs & ADC_CS_AINSEL_BITS) >> ADC_CS_AINSEL_LSB;
139}
140
150static inline void adc_set_round_robin(uint input_mask) {
151 valid_params_if(HARDWARE_ADC, input_mask < (1 << NUM_ADC_CHANNELS));
152 hw_write_masked(&adc_hw->cs, input_mask << ADC_CS_RROBIN_LSB, ADC_CS_RROBIN_BITS);
153}
154
161static inline void adc_set_temp_sensor_enabled(bool enable) {
162 if (enable)
163 hw_set_bits(&adc_hw->cs, ADC_CS_TS_EN_BITS);
164 else
165 hw_clear_bits(&adc_hw->cs, ADC_CS_TS_EN_BITS);
166}
167
175static inline uint16_t adc_read(void) {
176 hw_set_bits(&adc_hw->cs, ADC_CS_START_ONCE_BITS);
177
178 while (!(adc_hw->cs & ADC_CS_READY_BITS))
180
181 return (uint16_t) adc_hw->result;
182}
183
189static inline void adc_run(bool run) {
190 if (run)
191 hw_set_bits(&adc_hw->cs, ADC_CS_START_MANY_BITS);
192 else
193 hw_clear_bits(&adc_hw->cs, ADC_CS_START_MANY_BITS);
194}
195
204static inline void adc_set_clkdiv(float clkdiv) {
205 invalid_params_if(HARDWARE_ADC, clkdiv >= 1 << REG_FIELD_WIDTH(ADC_DIV_INT));
206 const int frac_bit_count = REG_FIELD_WIDTH(ADC_DIV_FRAC);
207#if PICO_ADC_CLKDIV_ROUND_NEAREST
208 clkdiv += 0.5f / (1 << frac_bit_count); // round to the nearest fraction
209#endif
210 adc_hw->div = (uint32_t)(clkdiv * (float) (1 << frac_bit_count));
211}
212
232 static inline void adc_fifo_setup(bool en, bool dreq_en, uint16_t dreq_thresh, bool err_in_fifo, bool byte_shift) {
233 hw_write_masked(&adc_hw->fcs,
234 (bool_to_bit(en) << ADC_FCS_EN_LSB) |
235 (bool_to_bit(dreq_en) << ADC_FCS_DREQ_EN_LSB) |
236 (((uint)dreq_thresh) << ADC_FCS_THRESH_LSB) |
237 (bool_to_bit(err_in_fifo) << ADC_FCS_ERR_LSB) |
238 (bool_to_bit(byte_shift) << ADC_FCS_SHIFT_LSB),
239 ADC_FCS_EN_BITS |
240 ADC_FCS_DREQ_EN_BITS |
241 ADC_FCS_THRESH_BITS |
242 ADC_FCS_ERR_BITS |
243 ADC_FCS_SHIFT_BITS
244 );
245}
246
252static inline bool adc_fifo_is_empty(void) {
253 return adc_hw->fcs & ADC_FCS_EMPTY_BITS;
254}
255
268static inline uint8_t adc_fifo_get_level(void) {
269 return (adc_hw->fcs & ADC_FCS_LEVEL_BITS) >> ADC_FCS_LEVEL_LSB;
270}
271
277static inline uint16_t adc_fifo_get(void) {
278 return (uint16_t)adc_hw->fifo;
279}
280
286static inline uint16_t adc_fifo_get_blocking(void) {
287 while (adc_fifo_is_empty())
289 return (uint16_t)adc_hw->fifo;
290}
291
297static inline void adc_fifo_drain(void) {
298 // Potentially there is still a conversion in progress -- wait for this to complete before draining
299 while (!(adc_hw->cs & ADC_CS_READY_BITS))
301 while (!adc_fifo_is_empty())
302 (void) adc_fifo_get();
303}
304
310static inline void adc_irq_set_enabled(bool enabled) {
311 adc_hw->inte = !!enabled;
312}
313
314#ifdef __cplusplus
315}
316#endif
317
318#endif
static void adc_set_round_robin(uint input_mask)
Round Robin sampling selector.
Definition adc.h:150
static void adc_fifo_setup(bool en, bool dreq_en, uint16_t dreq_thresh, bool err_in_fifo, bool byte_shift)
Setup the ADC FIFO.
Definition adc.h:232
void adc_init(void)
Initialise the ADC HW.
Definition adc.c:11
static void adc_set_clkdiv(float clkdiv)
Set the ADC Clock divisor.
Definition adc.h:204
static void adc_set_temp_sensor_enabled(bool enable)
Enable the onboard temperature sensor.
Definition adc.h:161
static void adc_select_input(uint input)
ADC input select.
Definition adc.h:118
static void adc_run(bool run)
Enable or disable free-running sampling mode.
Definition adc.h:189
static uint16_t adc_fifo_get_blocking(void)
Wait for the ADC FIFO to have data.
Definition adc.h:286
static uint16_t adc_fifo_get(void)
Get ADC result from FIFO.
Definition adc.h:277
static uint adc_get_selected_input(void)
Get the currently selected ADC input channel.
Definition adc.h:137
static void adc_gpio_init(uint gpio)
Initialise the gpio for use as an ADC pin.
Definition adc.h:95
static void adc_fifo_drain(void)
Drain the ADC FIFO.
Definition adc.h:297
static uint16_t adc_read(void)
Perform a single conversion.
Definition adc.h:175
static void adc_irq_set_enabled(bool enabled)
Enable/Disable ADC interrupts.
Definition adc.h:310
static uint8_t adc_fifo_get_level(void)
Get number of entries in the ADC FIFO.
Definition adc.h:268
static bool adc_fifo_is_empty(void)
Check FIFO empty state.
Definition adc.h:252
static __force_inline void hw_set_bits(io_rw_32 *addr, uint32_t mask)
Atomically set the specified bits to 1 in a HW register.
Definition address_mapped.h:135
static __force_inline void hw_write_masked(io_rw_32 *addr, uint32_t values, uint32_t write_mask)
Set new values for a sub-set of the bits in a HW register.
Definition address_mapped.h:171
static __force_inline void hw_clear_bits(io_rw_32 *addr, uint32_t mask)
Atomically clear the specified bits to 0 in a HW register.
Definition address_mapped.h:145
void gpio_set_function(uint gpio, gpio_function_t fn)
Select GPIO function.
Definition gpio.c:38
void gpio_set_input_enabled(uint gpio, bool enabled)
Enable GPIO input.
Definition gpio.c:270
static void gpio_disable_pulls(uint gpio)
Disable pulls on specified GPIO.
Definition gpio.h:337
@ GPIO_FUNC_NULL
Select NULL as GPIO pin function.
Definition io_bank0.h:41
static __force_inline void tight_loop_contents(void)
No-op function for the body of tight loops.
Definition platform.h:91