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mbed-os/targets/TARGET_NORDIC/TARGET_NRF5x/pwmout_api.c

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/*
* 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
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