1 /*
2 * Copyright (c) 2015 - 2018, 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 /**
50 * @brief Driver event types.
51 */
52 typedef enum
53 {
54 NRFX_ADC_EVT_DONE, ///< Event generated when the buffer is filled with samples.
55 NRFX_ADC_EVT_SAMPLE, ///< Event generated when the requested channel is sampled.
56 } nrfx_adc_evt_type_t;
57
58 /**
59 * @brief Analog-to-digital converter driver DONE event.
60 */
61 typedef struct
62 {
63 nrf_adc_value_t * p_buffer; ///< Pointer to the buffer with converted samples.
64 uint16_t size; ///< Number of samples in the buffer.
65 } nrfx_adc_done_evt_t;
66
67 /**
68 * @brief Analog-to-digital converter driver SAMPLE event.
69 */
70 typedef struct
71 {
72 nrf_adc_value_t sample; ///< Converted sample.
73 } nrfx_adc_sample_evt_t;
74
75 /**
76 * @brief Analog-to-digital converter driver event.
77 */
78 typedef struct
79 {
80 nrfx_adc_evt_type_t type; ///< Event type.
81 union
82 {
83 nrfx_adc_done_evt_t done; ///< Data for DONE event.
84 nrfx_adc_sample_evt_t sample; ///< Data for SAMPLE event.
85 } data;
86 } nrfx_adc_evt_t;
87
88 /**@brief Macro for initializing the ADC channel with the default configuration. */
89 #define NRFX_ADC_DEFAULT_CHANNEL(analog_input) \
90 { \
91 NULL, \
92 { \
93 .resolution = NRF_ADC_CONFIG_RES_10BIT, \
94 .scaling = NRF_ADC_CONFIG_SCALING_INPUT_FULL_SCALE, \
95 .reference = NRF_ADC_CONFIG_REF_VBG, \
96 .input = (analog_input), \
97 .extref = NRF_ADC_CONFIG_EXTREFSEL_NONE \
98 } \
99 }
100
101 // Forward declaration of the nrfx_adc_channel_t type.
102 typedef struct nrfx_adc_channel_s nrfx_adc_channel_t;
103
104 /**
105 * @brief ADC channel.
106 *
107 * This structure is defined by the user and used by the driver. Therefore, it should
108 * not be defined on the stack as a local variable.
109 */
110 struct nrfx_adc_channel_s
111 {
112 nrfx_adc_channel_t * p_next; ///< Pointer to the next enabled channel (for internal use).
113 nrf_adc_config_t config; ///< ADC configuration for the current channel.
114 };
115
116 /**
117 * @brief ADC configuration.
118 */
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_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 initial configuration.
146 * @param[in] event_handler Event handler provided by the user.
147 *
148 * @retval NRFX_SUCCESS If initialization was successful.
149 * @retval NRFX_ERROR_INVALID_STATE If 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 void nrfx_adc_channel_enable(nrfx_adc_channel_t * const p_channel);
174
175 /**
176 * @brief Function for disabling an ADC channel.
177 *
178 * This function can be called only when there is no conversion in progress
179 * (the ADC is not busy).
180 */
181 void nrfx_adc_channel_disable(nrfx_adc_channel_t * const p_channel);
182
183 /**
184 * @brief Function for disabling all ADC channels.
185 *
186 * This function can be called only when there is no conversion in progress
187 * (the ADC is not busy).
188 */
189 void nrfx_adc_all_channels_disable(void);
190
191 /**
192 * @brief Function for starting ADC sampling.
193 *
194 * This function triggers single ADC sampling. If more than one channel is enabled, the driver
195 * emulates scanning and all channels are sampled in the order they were enabled.
196 */
197 void nrfx_adc_sample(void);
198
199 /**
200 * @brief Function for executing a single ADC conversion.
201 *
202 * This function selects the desired input and starts a single conversion. If a valid pointer
203 * is provided for the result, the function blocks until the conversion is completed. Otherwise, the
204 * function returns when the conversion is started, and the result is provided in an event (driver
205 * must be initialized in non-blocking mode, otherwise an assertion will fail). The function will
206 * fail if ADC is busy. The channel does not need to be enabled to perform a single conversion.
207 *
208 * @param[in] p_channel Channel.
209 * @param[out] p_value Pointer to the location where the result should be placed. Unless NULL is
210 * provided, the function is blocking.
211 *
212 * @retval NRFX_SUCCESS If conversion was successful.
213 * @retval NRFX_ERROR_BUSY If the ADC driver is busy.
214 */
215 nrfx_err_t nrfx_adc_sample_convert(nrfx_adc_channel_t const * const p_channel,
216 nrf_adc_value_t * p_value);
217
218 /**
219 * @brief Function for converting data to the buffer.
220 *
221 * If the driver is initialized in non-blocking mode, this function returns when the first
222 * conversion is set up. When the buffer is filled, the application is notified by the event
223 * handler. If the driver is initialized in blocking mode, the function returns when the buffer is
224 * filled.
225 *
226 * Conversion is done on all enabled channels, but it is not triggered by this
227 * function. This function will prepare the ADC for sampling and then
228 * wait for the SAMPLE task. Sampling can be triggered manually by the @ref
229 * nrfx_adc_sample function or by PPI using the @ref NRF_ADC_TASK_START task.
230 *
231 * @note If more than one channel is enabled, the function emulates scanning, and
232 * a single START task will trigger conversion on all enabled channels. For example:
233 * If 3 channels are enabled and the user requests 6 samples, the completion event
234 * handler will be called after 2 START tasks.
235 *
236 * @note The application must adjust the sampling frequency. The maximum frequency
237 * depends on the sampling timer and the maximum latency of the ADC interrupt. If
238 * an interrupt is not handled before the next sampling is triggered, the sample
239 * will be lost.
240 *
241 * @param[in] buffer Result buffer.
242 * @param[in] size Buffer size in samples.
243 *
244 * @retval NRFX_SUCCESS If conversion was successful.
245 * @retval NRFX_ERROR_BUSY If the driver is busy.
246 */
247 nrfx_err_t nrfx_adc_buffer_convert(nrf_adc_value_t * buffer, uint16_t size);
248
249 /**
250 * @brief Function for retrieving the ADC state.
251 *
252 * @retval true If the ADC is busy.
253 * @retval false If the ADC is ready.
254 */
255 bool nrfx_adc_is_busy(void);
256
257 /**
258 * @brief Function for getting the address of the ADC START task.
259 *
260 * This function is used to get the address of the START task, which can be used to trigger ADC
261 * conversion.
262 *
263 * @return Start task address.
264 */
265 __STATIC_INLINE uint32_t nrfx_adc_start_task_get(void);
266
267 #ifndef SUPPRESS_INLINE_IMPLEMENTATION
268
nrfx_adc_start_task_get(void)269 __STATIC_INLINE uint32_t nrfx_adc_start_task_get(void)
270 {
271 return nrf_adc_task_address_get(NRF_ADC_TASK_START);
272 }
273
274 #endif
275
276
277 void nrfx_adc_irq_handler(void);
278
279
280 /** @} */
281
282 #ifdef __cplusplus
283 }
284 #endif
285
286 #endif // NRFX_ADC_H__
287