1 /*
2  * Copyright (c) 2022 - 2024, Nordic Semiconductor ASA
3  * All rights reserved.
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5  * SPDX-License-Identifier: BSD-3-Clause
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21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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32  */
33 
34 #include <nrfx_example.h>
35 #include <helpers/nrfx_gppi.h>
36 #include <nrfx_timer.h>
37 #include <nrfx_gpiote.h>
38 
39 #define NRFX_LOG_MODULE                 EXAMPLE
40 #define NRFX_EXAMPLE_CONFIG_LOG_ENABLED 1
41 #define NRFX_EXAMPLE_CONFIG_LOG_LEVEL   3
42 #include <nrfx_log.h>
43 
44 /**
45  * @defgroup nrfx_gppi_fork_example Fork GPPI example
46  * @{
47  * @ingroup nrfx_gppi_examples
48  *
49  * @brief Example showing basic fork functionality of a nrfx_gppi helper.
50  *
51  * @details Application initializes nrfx_gpiote, nrfx_timer drivers and nrfx_gppi helper in a way that
52  *          TIMER compare event is set up to be forwarded via PPI/DPPI to GPIOTE and toggle a pin.
53  *          Fork mechanism in PPI/DPPI is also set up to toggle a second pin in GPIOTE at the same time.
54  */
55 
56 /** @brief Symbol specifying timer instance to be used. */
57 #define TIMER_INST_IDX 0
58 
59 /** @brief Symbol specifying time in milliseconds to wait for handler execution. */
60 #define TIME_TO_WAIT_MS 1000UL
61 
62 /** @brief Symbol specifying GPIOTE instance to be used. */
63 #define GPIOTE_INST_IDX 0
64 
65 /** @brief Symbol specifying output pin associated with primary task. */
66 #define OUTPUT_PIN_PRIMARY LED1_PIN
67 
68 /** @brief Symbol specifying output pin associated with fork task. */
69 #define OUTPUT_PIN_FORK LED2_PIN
70 
71 /**
72  * @brief Function for handling TIMER driver events.
73  *
74  * @param[in] event_type Timer event.
75  * @param[in] p_context  General purpose parameter set during initialization of the timer.
76  *                       This parameter can be used to pass additional information to the handler
77  *                       function, for example the timer ID.
78  */
timer_handler(nrf_timer_event_t event_type,void * p_context)79 static void timer_handler(nrf_timer_event_t event_type, void * p_context)
80 {
81     if (event_type == NRF_TIMER_EVENT_COMPARE0)
82     {
83         char * p_msg = p_context;
84         NRFX_LOG_INFO("Timer finished. Context passed to the handler: >%s<", p_msg);
85         NRFX_LOG_INFO("GPIOTE output pin (primary): %d is %s", OUTPUT_PIN_PRIMARY,
86                       nrfx_gpiote_in_is_set(OUTPUT_PIN_PRIMARY) ? "high" : "low");
87         NRFX_LOG_INFO("GPIOTE output pin (fork): %d is %s", OUTPUT_PIN_FORK,
88                       nrfx_gpiote_in_is_set(OUTPUT_PIN_FORK) ? "high" : "low");
89     }
90 }
91 
92 /**
93  * @brief Function for application main entry.
94  *
95  * @return Nothing.
96  */
main(void)97 int main(void)
98 {
99     nrfx_err_t status;
100     (void)status;
101 
102     uint8_t out_channel_primary, out_channel_fork;
103     uint8_t gppi_channel;
104 
105 #if defined(__ZEPHYR__)
106     IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_TIMER_INST_GET(TIMER_INST_IDX)), IRQ_PRIO_LOWEST,
107                 NRFX_TIMER_INST_HANDLER_GET(TIMER_INST_IDX), 0, 0);
108     IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_GPIOTE_INST_GET(GPIOTE_INST_IDX)), IRQ_PRIO_LOWEST,
109                 NRFX_GPIOTE_INST_HANDLER_GET(GPIOTE_INST_IDX), 0, 0);
110 #endif
111 
112     NRFX_EXAMPLE_LOG_INIT();
113 
114     NRFX_LOG_INFO("Starting nrfx_gppi basic fork example.");
115     NRFX_EXAMPLE_LOG_PROCESS();
116 
117     nrfx_gpiote_t const gpiote_inst = NRFX_GPIOTE_INSTANCE(GPIOTE_INST_IDX);
118     status = nrfx_gpiote_init(&gpiote_inst, NRFX_GPIOTE_DEFAULT_CONFIG_IRQ_PRIORITY);
119     NRFX_ASSERT(status == NRFX_SUCCESS);
120     NRFX_LOG_INFO("GPIOTE status: %s",
121                   nrfx_gpiote_init_check(&gpiote_inst) ? "initialized" : "not initialized");
122 
123     status = nrfx_gpiote_channel_alloc(&gpiote_inst, &out_channel_primary);
124     NRFX_ASSERT(status == NRFX_SUCCESS);
125 
126     status = nrfx_gpiote_channel_alloc(&gpiote_inst, &out_channel_fork);
127     NRFX_ASSERT(status == NRFX_SUCCESS);
128 
129     /*
130      * Initialize the output pin associated with the primary task.
131      * The SET task will turn the LED on, CLR will turn it off, and OUT will toggle it.
132     */
133     static const nrfx_gpiote_output_config_t output_config =
134     {
135         .drive = NRF_GPIO_PIN_S0S1,
136         .input_connect = NRF_GPIO_PIN_INPUT_DISCONNECT,
137         .pull = NRF_GPIO_PIN_NOPULL,
138     };
139 
140     nrfx_gpiote_task_config_t task_config =
141     {
142         .task_ch = out_channel_primary,
143         .polarity = NRF_GPIOTE_POLARITY_TOGGLE,
144         .init_val = NRF_GPIOTE_INITIAL_VALUE_HIGH,
145     };
146 
147     status = nrfx_gpiote_output_configure(&gpiote_inst,
148                                           OUTPUT_PIN_PRIMARY,
149                                           &output_config,
150                                           &task_config);
151     NRFX_ASSERT(status == NRFX_SUCCESS);
152 
153     nrfx_gpiote_out_task_enable(&gpiote_inst, OUTPUT_PIN_PRIMARY);
154 
155     /*
156      * Initialize the output pin associated with the fork task.
157      * The SET task will turn the LED off, CLR will turn it on, and OUT will toggle it.
158      */
159     task_config.task_ch = out_channel_fork;
160     task_config.init_val = NRF_GPIOTE_INITIAL_VALUE_LOW;
161 
162     status = nrfx_gpiote_output_configure(&gpiote_inst,
163                                           OUTPUT_PIN_FORK,
164                                           &output_config,
165                                           &task_config);
166     NRFX_ASSERT(status == NRFX_SUCCESS);
167 
168     nrfx_gpiote_out_task_enable(&gpiote_inst, OUTPUT_PIN_FORK);
169 
170     nrfx_timer_t timer_inst = NRFX_TIMER_INSTANCE(TIMER_INST_IDX);
171     uint32_t base_frequency = NRF_TIMER_BASE_FREQUENCY_GET(timer_inst.p_reg);
172     nrfx_timer_config_t timer_config = NRFX_TIMER_DEFAULT_CONFIG(base_frequency);
173     timer_config.bit_width = NRF_TIMER_BIT_WIDTH_32;
174     timer_config.p_context = "Some context";
175 
176     status = nrfx_timer_init(&timer_inst, &timer_config, timer_handler);
177     NRFX_ASSERT(status == NRFX_SUCCESS);
178 
179     nrfx_timer_clear(&timer_inst);
180 
181     /* Create variable desired_ticks to store the output of nrfx_timer_ms_to_ticks function. */
182     uint32_t desired_ticks = nrfx_timer_ms_to_ticks(&timer_inst, TIME_TO_WAIT_MS);
183     NRFX_LOG_INFO("Time to wait: %lu ms", TIME_TO_WAIT_MS);
184 
185     /*
186      * Set the timer channel NRF_TIMER_CC_CHANNEL0 in the extended compare mode to clear
187      * the timer and to trigger an interrupt if the internal counter register is equal to
188      * desired_ticks.
189      */
190     nrfx_timer_extended_compare(&timer_inst, NRF_TIMER_CC_CHANNEL0, desired_ticks,
191                                 NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, true);
192 
193     status = nrfx_gppi_channel_alloc(&gppi_channel);
194     NRFX_ASSERT(status == NRFX_SUCCESS);
195 
196     /*
197      * Configure endpoints of the channel so that the input timer event is connected with the output
198      * pin OUT task. This means that each time the timer interrupt occurs, the LED pin will be toggled.
199     */
200     nrfx_gppi_channel_endpoints_setup(gppi_channel,
201         nrfx_timer_compare_event_address_get(&timer_inst, NRF_TIMER_CC_CHANNEL0),
202         nrfx_gpiote_out_task_address_get(&gpiote_inst, OUTPUT_PIN_PRIMARY));
203 
204     /*
205      * Set up the task endpoint for a given PPI fork or for associating the DPPI channel
206      * with an additional task register depending on which driver the GPPI helper is using.
207     */
208     nrfx_gppi_fork_endpoint_setup(gppi_channel,
209                                   nrfx_gpiote_out_task_address_get(&gpiote_inst, OUTPUT_PIN_FORK));
210 
211     nrfx_gppi_channels_enable(BIT(gppi_channel));
212 
213     nrfx_timer_enable(&timer_inst);
214     NRFX_LOG_INFO("Timer status: %s", nrfx_timer_is_enabled(&timer_inst) ? "enabled" : "disabled");
215 
216     while (1)
217     {
218         NRFX_EXAMPLE_LOG_PROCESS();
219     }
220 }
221 
222 /** @} */
223