Diff: targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/pwmout_api.c

Revision:

186:707f6e361f3e

Child:

189:f392fc9709a3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/pwmout_api.c	Fri Jun 22 16:45:37 2018 +0100
@@ -0,0 +1,338 @@
+/*
+ * Copyright (c) 2018 Nordic Semiconductor ASA
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright notice, this list
+ *      of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form, except as embedded into a Nordic Semiconductor ASA
+ *      integrated circuit in a product or a software update for such product, must reproduce
+ *      the above copyright notice, this list of conditions and the following disclaimer in
+ *      the documentation and/or other materials provided with the distribution.
+ *
+ *   3. Neither the name of Nordic Semiconductor ASA nor the names of its contributors may be
+ *      used to endorse or promote products derived from this software without specific prior
+ *      written permission.
+ *
+ *   4. This software, with or without modification, must only be used with a
+ *      Nordic Semiconductor ASA integrated circuit.
+ *
+ *   5. Any software provided in binary or object form under this license must not be reverse
+ *      engineered, decompiled, modified and/or disassembled.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#if DEVICE_PWMOUT
+
+#include "hal/pwmout_api.h"
+
+#include "pinmap_ex.h"
+#include "nrf_drv_pwm.h"
+
+#if 0
+#define DEBUG_PRINTF(...) do { printf(__VA_ARGS__); } while(0)
+#else
+#define DEBUG_PRINTF(...) {}
+#endif
+
+/* 0x7FFF is the max of COUNTERTOP pulse for the PWM peripherial of the nRF52. */
+#define MAX_PWM_COUNTERTOP  (0x7FFF)
+
+/* The PWM is driven by a 1 MHz clock to fit the 1 us resolution expected by the API. */
+#define MAX_PWM_PERIOD_US   (MAX_PWM_COUNTERTOP)
+#define MAX_PWM_PERIOD_MS   (MAX_PWM_PERIOD_US / 1000)
+#define MAX_PWM_PERIOD_S    ((float) MAX_PWM_PERIOD_US / 1000000.0f)
+
+/* Allocate PWM instances. */
+static nrf_drv_pwm_t nordic_nrf5_pwm_instance[] = {
+#if PWM0_ENABLED
+    NRF_DRV_PWM_INSTANCE(0),
+#endif
+#if PWM1_ENABLED
+    NRF_DRV_PWM_INSTANCE(1),
+#endif
+#if PWM2_ENABLED
+    NRF_DRV_PWM_INSTANCE(2),
+#endif
+#if PWM3_ENABLED
+    NRF_DRV_PWM_INSTANCE(3),
+#endif
+};
+
+/* Helper function for (re)initializing the PWM instance.
+ */
+static void nordic_pwm_init(pwmout_t *obj)
+{
+    MBED_ASSERT(obj);
+
+    /* Default configuration:
+     * 1 pin per instance, otherwise they would share base count.
+     * 1 MHz clock source to match the 1 us resolution.
+     */
+    nrf_drv_pwm_config_t config = {
+        .output_pins  = {
+            obj->pin,
+            NRF_DRV_PWM_PIN_NOT_USED,
+            NRF_DRV_PWM_PIN_NOT_USED,
+            NRF_DRV_PWM_PIN_NOT_USED,
+        },
+        .irq_priority = PWM_DEFAULT_CONFIG_IRQ_PRIORITY,
+        .base_clock   = NRF_PWM_CLK_1MHz,
+        .count_mode   = NRF_PWM_MODE_UP,
+        .top_value    = obj->period,
+        .load_mode    = NRF_PWM_LOAD_COMMON,
+        .step_mode    = NRF_PWM_STEP_AUTO,
+    };
+
+    /* Make sure PWM instance is not running before making changes. */
+    nrf_drv_pwm_uninit(&nordic_nrf5_pwm_instance[obj->instance]);
+
+    /* Initialize instance with new configuration. */
+    ret_code_t result = nrf_drv_pwm_init(&nordic_nrf5_pwm_instance[obj->instance],
+                                         &config,
+                                         NULL);
+
+    MBED_ASSERT(result == NRF_SUCCESS);
+}
+
+/* Helper function for reinitializing the PWM instance and setting the duty-cycle. */
+static void nordic_pwm_restart(pwmout_t *obj)
+{
+    MBED_ASSERT(obj);
+
+    /* (Re)initialize PWM instance. */
+    nordic_pwm_init(obj);
+
+    /* Set duty-cycle from object. */
+    ret_code_t result = nrf_drv_pwm_simple_playback(&nordic_nrf5_pwm_instance[obj->instance],
+                                                    &obj->sequence,
+                                                    1,
+                                                    NRF_DRV_PWM_FLAG_LOOP);
+
+    MBED_ASSERT(result == NRF_SUCCESS);
+}
+
+/** Initialize the pwm out peripheral and configure the pin
+ *
+ * Parameter obj The pwmout object to initialize
+ * Parameter pin The pwmout pin to initialize
+ */
+void pwmout_init(pwmout_t *obj, PinName pin)
+{
+    DEBUG_PRINTF("pwmout_init: %d\r\n", pin);
+
+    MBED_ASSERT(obj);
+
+    /* Get hardware instance from pinmap. */
+    int instance = pin_instance_pwm(pin);
+
+    MBED_ASSERT(instance < (int)(sizeof(nordic_nrf5_pwm_instance) / sizeof(nrf_drv_pwm_t)));
+
+    /* Populate PWM object with default values. */
+    obj->instance = instance;
+    obj->pin = pin;
+    obj->pulse = 0;
+    obj->period = MAX_PWM_COUNTERTOP;
+    obj->percent = 0;
+    obj->sequence.values.p_common = &obj->pulse;
+    obj->sequence.length = NRF_PWM_VALUES_LENGTH(obj->pulse);
+    obj->sequence.repeats = 0;
+    obj->sequence.end_delay = 0;
+
+    /* Initialize PWM instance. */
+    nordic_pwm_init(obj);
+}
+
+/** Deinitialize the pwmout object
+ *
+ * Parameter obj The pwmout object
+ */
+void pwmout_free(pwmout_t *obj)
+{
+    DEBUG_PRINTF("pwmout_free\r\n");
+
+    MBED_ASSERT(obj);
+
+    /* Uninitialize PWM instance. */
+    nrf_drv_pwm_uninit(&nordic_nrf5_pwm_instance[obj->instance]);
+}
+
+/** Set the output duty-cycle in range <0.0f, 1.0f>
+ *
+ * pulse 0.0f represents 0 percentage, 1.0f represents 100 percent.
+ * Parameter obj     The pwmout object
+ * Parameter percent The floating-point percentage number
+ */
+void pwmout_write(pwmout_t *obj, float percent)
+{
+    DEBUG_PRINTF("pwmout_write: %f\r\n", percent);
+
+    /* Find counts based on period. */
+    uint16_t pulse = obj->period * percent;
+
+    /* Ensure we don't overcount. */
+    obj->pulse = (pulse > MAX_PWM_COUNTERTOP) ? MAX_PWM_COUNTERTOP : pulse;
+
+    /* Store actual percentage passed as parameter to avoid floating point rounding errors. */
+    obj->percent = percent;
+
+    /* Set new duty-cycle. */
+    ret_code_t result = nrf_drv_pwm_simple_playback(&nordic_nrf5_pwm_instance[obj->instance],
+                                                    &obj->sequence,
+                                                    1,
+                                                    NRF_DRV_PWM_FLAG_LOOP);
+
+    MBED_ASSERT(result == NRF_SUCCESS);
+}
+
+/** Read the current float-point output duty-cycle
+ *
+ * Parameter obj The pwmout object
+ * Return A floating-point output duty-cycle
+ */
+float pwmout_read(pwmout_t *obj)
+{
+    DEBUG_PRINTF("pwmout_read: %f\r\n", obj->percent);
+
+    /* Return percentage stored in object instead of calculating the value.
+     * This prevents floating point rounding errors.
+     */
+    return obj->percent;
+}
+
+/** Set the PWM period specified in seconds, keeping the duty cycle the same
+ *
+ * Periods smaller than microseconds (the lowest resolution) are set to zero.
+ * Parameter obj     The pwmout object
+ * Parameter seconds The floating-point seconds period
+ */
+void pwmout_period(pwmout_t *obj, float period)
+{
+    DEBUG_PRINTF("pwmout_period: %f\r\n", period);
+
+    /* Cap period if too large. */
+    if (period > MAX_PWM_PERIOD_S) {
+        period = MAX_PWM_PERIOD_S;
+    }
+
+    /* Set new period. */
+    pwmout_period_us(obj, period * 1000000);
+}
+
+/** Set the PWM period specified in miliseconds, keeping the duty cycle the same
+ *
+ * Parameter obj The pwmout object
+ * Parameter ms  The milisecond period
+ */
+void pwmout_period_ms(pwmout_t *obj, int period)
+{
+    DEBUG_PRINTF("pwmout_period_ms: %d\r\n", period);
+
+    /* Cap period if too large. */
+    if (period > MAX_PWM_PERIOD_MS) {
+        period = MAX_PWM_PERIOD_MS;
+    }
+
+    /* Set new period. */
+    pwmout_period_us(obj, period * 1000);
+}
+
+/** Set the PWM period specified in microseconds, keeping the duty cycle the same
+ *
+ * Parameter obj The pwmout object
+ * Parameter us  The microsecond period
+ */
+void pwmout_period_us(pwmout_t *obj, int period)
+{
+    DEBUG_PRINTF("pwmout_period_us: %d\r\n", period);
+
+    /* Cap period if too large. */
+    if (period > MAX_PWM_PERIOD_US) {
+        period = MAX_PWM_PERIOD_US;
+    }
+
+    /* Scale new count based on stored duty-cycle and new period. */
+    uint32_t pulse = (period * obj->pulse) / obj->period;
+
+    /* Store new values in object. */
+    obj->pulse = pulse;
+    obj->period = period;
+    obj->percent = (float) pulse / (float) period;
+
+    /* Restart instance with new values. */
+    nordic_pwm_restart(obj);
+}
+
+/** Set the PWM pulsewidth specified in seconds, keeping the period the same.
+ *
+ * Parameter obj     The pwmout object
+ * Parameter seconds The floating-point pulsewidth in seconds
+ */
+void pwmout_pulsewidth(pwmout_t *obj, float pulse)
+{
+    DEBUG_PRINTF("pwmout_pulsewidt: %f\r\n", pulse);
+
+    /* Cap pulsewidth to period before setting it. */
+    if ((pulse * 1000000) > (float) obj->pulse) {
+        obj->pulse = obj->period;
+        pwmout_pulsewidth_us(obj, obj->pulse);
+    } else {
+        pwmout_pulsewidth_us(obj, pulse * 1000000);
+    }
+}
+
+/** Set the PWM pulsewidth specified in miliseconds, keeping the period the same.
+ *
+ * Parameter obj The pwmout object
+ * Parameter ms  The floating-point pulsewidth in miliseconds
+ */
+void pwmout_pulsewidth_ms(pwmout_t *obj, int pulse)
+{
+    DEBUG_PRINTF("pwmout_pulsewidth_ms: %d\r\n", ms);
+
+    /* Cap pulsewidth to period before setting it. */
+    if ((pulse * 1000) > (int) obj->period) {
+        obj->pulse = obj->period;
+        pwmout_pulsewidth_us(obj, obj->pulse);
+    } else {
+        pwmout_pulsewidth_us(obj, pulse * 1000);
+    }
+}
+
+/** Set the PWM pulsewidth specified in microseconds, keeping the period the same.
+ *
+ * Parameter obj The pwmout object
+ * Parameter us  The floating-point pulsewidth in microseconds
+ */
+void pwmout_pulsewidth_us(pwmout_t *obj, int pulse)
+{
+    DEBUG_PRINTF("pwmout_pulsewidth_us: %d\r\n", pulse);
+
+    /* Cap pulsewidth to period. */
+    if (pulse > obj->period) {
+        pulse = obj->period;
+    }
+
+    /* Store new values in object. */
+    obj->pulse = pulse;
+    obj->percent = (float) pulse / (float) obj->period;
+
+    /* Restart instance with new values. */
+    nordic_pwm_restart(obj);
+}
+
+#endif // DEVICE_PWMOUT