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Fix for nrf52 pwm issues #7779

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Merged
merged 2 commits into from
Sep 6, 2018
Merged

Fix for nrf52 pwm issues #7779

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e1d5019
Fix for issue #7743 NRF52 Cannot initialize PWM
Aug 13, 2018
2aa67b8
Fix for issue #7707 PwmOut inverted
Aug 13, 2018
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41 changes: 27 additions & 14 deletions targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/pwmout_api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,9 @@
#define MAX_PWM_PERIOD_MS (MAX_PWM_PERIOD_US / 1000)
#define MAX_PWM_PERIOD_S ((float) MAX_PWM_PERIOD_US / 1000000.0f)

/* Sequence bit that denotes the polarity of the pwm waveform. */
#define SEQ_POLARITY_BIT (0x8000)

/* Allocate PWM instances. */
static nrf_drv_pwm_t nordic_nrf5_pwm_instance[] = {
#if PWM0_ENABLED
Expand Down Expand Up @@ -98,9 +101,6 @@ static void nordic_pwm_init(pwmout_t *obj)
.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,
Expand All @@ -114,6 +114,9 @@ static void nordic_pwm_restart(pwmout_t *obj)
{
MBED_ASSERT(obj);

/* Uninitialize PWM instace */
nrf_drv_pwm_uninit(&nordic_nrf5_pwm_instance[obj->instance]);

/* (Re)initialize PWM instance. */
nordic_pwm_init(obj);

Expand All @@ -140,7 +143,7 @@ void pwmout_init(pwmout_t *obj, PinName pin)
/* 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)));
MBED_ASSERT(instance < (int) (sizeof(nordic_nrf5_pwm_instance) / sizeof(nrf_drv_pwm_t)));

/* Populate PWM object with default values. */
obj->instance = instance;
Expand All @@ -153,6 +156,9 @@ void pwmout_init(pwmout_t *obj, PinName pin)
obj->sequence.repeats = 0;
obj->sequence.end_delay = 0;

/* Set active low logic. */
obj->pulse |= SEQ_POLARITY_BIT;

/* Initialize PWM instance. */
nordic_pwm_init(obj);
}
Expand Down Expand Up @@ -184,17 +190,20 @@ void pwmout_write(pwmout_t *obj, float percent)
/* Find counts based on period. */
uint16_t pulse = obj->period * percent;

/* Clear sequence, but keep the polarity bit */
obj->pulse &= SEQ_POLARITY_BIT;

/* Ensure we don't overcount. */
obj->pulse = (pulse > MAX_PWM_COUNTERTOP) ? MAX_PWM_COUNTERTOP : pulse;
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);
&obj->sequence,
1,
NRF_DRV_PWM_FLAG_LOOP);

MBED_ASSERT(result == NRF_SUCCESS);
}
Expand Down Expand Up @@ -266,10 +275,11 @@ void pwmout_period_us(pwmout_t *obj, int period)
}

/* Scale new count based on stored duty-cycle and new period. */
uint32_t pulse = (period * obj->pulse) / obj->period;
uint32_t pulse = (period * (obj->pulse & ~SEQ_POLARITY_BIT)) / obj->period;

/* Store new values in object. */
obj->pulse = pulse;
obj->pulse &= SEQ_POLARITY_BIT;
obj->pulse |= pulse;
obj->period = period;
obj->percent = (float) pulse / (float) period;

Expand All @@ -287,8 +297,9 @@ 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;
if ((pulse * 1000000) > (float) (obj->pulse & ~SEQ_POLARITY_BIT)) {
obj->pulse &= SEQ_POLARITY_BIT;
obj->pulse |= obj->period;
pwmout_pulsewidth_us(obj, obj->pulse);
} else {
pwmout_pulsewidth_us(obj, pulse * 1000000);
Expand All @@ -306,7 +317,8 @@ void pwmout_pulsewidth_ms(pwmout_t *obj, int pulse)

/* Cap pulsewidth to period before setting it. */
if ((pulse * 1000) > (int) obj->period) {
obj->pulse = obj->period;
obj->pulse &= SEQ_POLARITY_BIT;
obj->pulse |= obj->period;
pwmout_pulsewidth_us(obj, obj->pulse);
} else {
pwmout_pulsewidth_us(obj, pulse * 1000);
Expand All @@ -328,7 +340,8 @@ void pwmout_pulsewidth_us(pwmout_t *obj, int pulse)
}

/* Store new values in object. */
obj->pulse = pulse;
obj->pulse &= SEQ_POLARITY_BIT;
obj->pulse |= pulse;
obj->percent = (float) pulse / (float) obj->period;

/* Restart instance with new values. */
Expand Down