1 /*
2 * Copyright (c) 2015 - 2020, Nordic Semiconductor ASA
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * 3. Neither the name of the copyright holder nor the names of its
16 * contributors may be used to endorse or promote products derived from this
17 * software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
23 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #ifndef NRFX_ADC_H__
33 #define NRFX_ADC_H__
34
35 #include <nrfx.h>
36 #include <hal/nrf_adc.h>
37
38 #ifdef __cplusplus
39 extern "C" {
40 #endif
41
42 /**
43 * @defgroup nrfx_adc ADC driver
44 * @{
45 * @ingroup nrf_adc
46 * @brief Analog-to-Digital Converter (ADC) peripheral driver.
47 */
48
49 /** @brief Driver event types. */
50 typedef enum
51 {
52 NRFX_ADC_EVT_DONE, ///< Event generated when the buffer is filled with samples.
53 NRFX_ADC_EVT_SAMPLE, ///< Event generated when the requested channel is sampled.
54 } nrfx_adc_evt_type_t;
55
56 /** @brief ADC driver DONE event structure. */
57 typedef struct
58 {
59 nrf_adc_value_t * p_buffer; ///< Pointer to the buffer with converted samples.
60 uint16_t size; ///< Number of samples in the buffer.
61 } nrfx_adc_done_evt_t;
62
63 /** @brief SAMPLE event structure. */
64 typedef struct
65 {
66 nrf_adc_value_t sample; ///< Converted sample.
67 } nrfx_adc_sample_evt_t;
68
69 /** @brief ADC driver event. */
70 typedef struct
71 {
72 nrfx_adc_evt_type_t type; ///< Event type.
73 union
74 {
75 nrfx_adc_done_evt_t done; ///< Data for DONE event.
76 nrfx_adc_sample_evt_t sample; ///< Data for SAMPLE event.
77 } data; ///< Union to store event data.
78 } nrfx_adc_evt_t;
79
80 /**
81 * @brief ADC channel default configuration.
82 *
83 * This configuration sets up ADC channel with the following options:
84 * - 10 bits resolution
85 * - full scale input
86 * - reference voltage: 1.2 V
87 * - external reference input disabled
88 *
89 * @param[in] analog_input Analog input.
90 */
91 #define NRFX_ADC_DEFAULT_CHANNEL(analog_input) \
92 { \
93 NULL, \
94 { \
95 .resolution = NRF_ADC_CONFIG_RES_10BIT, \
96 .scaling = NRF_ADC_CONFIG_SCALING_INPUT_FULL_SCALE, \
97 .reference = NRF_ADC_CONFIG_REF_VBG, \
98 .input = (nrf_adc_config_input_t)analog_input, \
99 .extref = NRF_ADC_CONFIG_EXTREFSEL_NONE \
100 } \
101 }
102
103 /** @brief Forward declaration of the nrfx_adc_channel_t type. */
104 typedef struct nrfx_adc_channel_s nrfx_adc_channel_t;
105
106 /**
107 * @brief ADC channel.
108 *
109 * This structure is defined by the user and used by the driver. Therefore, it should
110 * not be defined on the stack as a local variable.
111 */
112 struct nrfx_adc_channel_s
113 {
114 nrfx_adc_channel_t * p_next; ///< Pointer to the next enabled channel (for internal use).
115 nrf_adc_config_t config; ///< ADC configuration for the current channel.
116 };
117
118 /** @brief ADC configuration. */
119 typedef struct
120 {
121 uint8_t interrupt_priority; ///< Priority of ADC interrupt.
122 } nrfx_adc_config_t;
123
124 /** @brief ADC default configuration. */
125 #define NRFX_ADC_DEFAULT_CONFIG \
126 { \
127 .interrupt_priority = NRFX_ADC_DEFAULT_CONFIG_IRQ_PRIORITY \
128 }
129
130 /**
131 * @brief User event handler prototype.
132 *
133 * This function is called when the requested number of samples has been processed.
134 *
135 * @param p_event Event.
136 */
137 typedef void (*nrfx_adc_event_handler_t)(nrfx_adc_evt_t const * p_event);
138
139 /**
140 * @brief Function for initializing the ADC.
141 *
142 * If a valid event handler is provided, the driver is initialized in non-blocking mode.
143 * If event_handler is NULL, the driver works in blocking mode.
144 *
145 * @param[in] p_config Pointer to the structure with the initial configuration.
146 * @param[in] event_handler Event handler provided by the user.
147 *
148 * @retval NRFX_SUCCESS Initialization was successful.
149 * @retval NRFX_ERROR_INVALID_STATE The driver is already initialized.
150 */
151 nrfx_err_t nrfx_adc_init(nrfx_adc_config_t const * p_config,
152 nrfx_adc_event_handler_t event_handler);
153
154 /**
155 * @brief Function for uninitializing the ADC.
156 *
157 * This function stops all ongoing conversions and disables all channels.
158 */
159 void nrfx_adc_uninit(void);
160
161 /**
162 * @brief Function for enabling an ADC channel.
163 *
164 * This function configures and enables the channel. When @ref nrfx_adc_buffer_convert is
165 * called, all channels that have been enabled with this function are sampled.
166 *
167 * This function can be called only when there is no conversion in progress
168 * (the ADC is not busy).
169 *
170 * @note The channel instance variable @p p_channel is used by the driver as an item
171 * in a list. Therefore, it cannot be an automatic variable that is located on the stack.
172 *
173 * @param[in] p_channel Pointer to the channel instance.
174 */
175 void nrfx_adc_channel_enable(nrfx_adc_channel_t * const p_channel);
176
177 /**
178 * @brief Function for disabling an ADC channel.
179 *
180 * This function can be called only when there is no conversion in progress
181 * (the ADC is not busy).
182 *
183 * @param p_channel Pointer to the channel instance.
184 */
185 void nrfx_adc_channel_disable(nrfx_adc_channel_t * const p_channel);
186
187 /**
188 * @brief Function for disabling all ADC channels.
189 *
190 * This function can be called only when there is no conversion in progress
191 * (the ADC is not busy).
192 */
193 void nrfx_adc_all_channels_disable(void);
194
195 /**
196 * @brief Function for starting ADC sampling.
197 *
198 * This function triggers single ADC sampling. If more than one channel is enabled, the driver
199 * emulates scanning and all channels are sampled in the order they were enabled.
200 */
201 void nrfx_adc_sample(void);
202
203 /**
204 * @brief Function for executing a single ADC conversion.
205 *
206 * This function selects the desired input and starts a single conversion. If a valid pointer
207 * is provided for the result, the function blocks until the conversion is completed. Otherwise, the
208 * function returns when the conversion is started, and the result is provided in an event (driver
209 * must be initialized in non-blocking mode, otherwise an assertion will fail). The function will
210 * fail if ADC is busy. The channel does not need to be enabled to perform a single conversion.
211 *
212 * @param[in] p_channel Channel.
213 * @param[out] p_value Pointer to the location where the result is to be placed. Unless NULL is
214 * provided, the function is blocking.
215 *
216 * @retval NRFX_SUCCESS Conversion was successful.
217 * @retval NRFX_ERROR_BUSY The ADC driver is busy.
218 */
219 nrfx_err_t nrfx_adc_sample_convert(nrfx_adc_channel_t const * p_channel,
220 nrf_adc_value_t * p_value);
221
222 /**
223 * @brief Function for converting data to the buffer.
224 *
225 * If the driver is initialized in non-blocking mode, this function returns when the first
226 * conversion is set up. When the buffer is filled, the application is notified by the event
227 * handler. If the driver is initialized in blocking mode, the function returns when the buffer is
228 * filled.
229 *
230 * Conversion is done on all enabled channels, but it is not triggered by this
231 * function. This function will prepare the ADC for sampling and then
232 * wait for the SAMPLE task. Sampling can be triggered manually by the @ref
233 * nrfx_adc_sample function or by PPI using the @ref NRF_ADC_TASK_START task.
234 *
235 * @note If more than one channel is enabled, the function emulates scanning, and
236 * a single START task will trigger conversion on all enabled channels. For example:
237 * If 3 channels are enabled and the user requests 6 samples, the completion event
238 * handler will be called after 2 START tasks.
239 *
240 * @note The application must adjust the sampling frequency. The maximum frequency
241 * depends on the sampling timer and the maximum latency of the ADC interrupt. If
242 * an interrupt is not handled before the next sampling is triggered, the sample
243 * will be lost.
244 *
245 * @param[in] buffer Result buffer.
246 * @param[in] size Buffer size in samples.
247 *
248 * @retval NRFX_SUCCESS Conversion was successful.
249 * @retval NRFX_ERROR_BUSY The driver is busy.
250 */
251 nrfx_err_t nrfx_adc_buffer_convert(nrf_adc_value_t * buffer, uint16_t size);
252
253 /**
254 * @brief Function for retrieving the ADC state.
255 *
256 * @retval true The ADC is busy.
257 * @retval false The ADC is ready.
258 */
259 bool nrfx_adc_is_busy(void);
260
261 /**
262 * @brief Function for getting the address of the ADC START task.
263 *
264 * This function is used to get the address of the START task, which can be used to trigger ADC
265 * conversion.
266 *
267 * @return Start task address.
268 */
269 NRFX_STATIC_INLINE uint32_t nrfx_adc_start_task_get(void);
270
271 #ifndef NRFX_DECLARE_ONLY
nrfx_adc_start_task_get(void)272 NRFX_STATIC_INLINE uint32_t nrfx_adc_start_task_get(void)
273 {
274 return nrf_adc_task_address_get(NRF_ADC, NRF_ADC_TASK_START);
275 }
276 #endif // NRFX_DECLARE_ONLY
277
278 /** @} */
279
280
281 void nrfx_adc_irq_handler(void);
282
283
284 #ifdef __cplusplus
285 }
286 #endif
287
288 #endif // NRFX_ADC_H__
289