Merge pull request #104 from sdalu/pwmfix
Use active wait and perform extra toggle if needed.
This commit is contained in:
commit
bc6033e829
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@ -18,6 +18,11 @@
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* @file hal_pwm_lld.c
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* @brief NRF51 PWM subsystem low level driver source.
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*
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* @note Using the method described in nrf51-pwm-library to correctly
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* handle toggling of the pin with GPIOTE when changing period.
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* It means it is generally unsafe to use GPIOTE with a period
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* less than (2 * PWM_GPIOTE_DECISION_TIME / 16MHz)
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*
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* @addtogroup PWM
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* @{
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*/
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@ -30,6 +35,8 @@
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/* Driver local definitions. */
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/*===========================================================================*/
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#define PWM_GPIOTE_PPI_CC 3
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#define PWM_GPIOTE_DECISION_TIME 160
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/*===========================================================================*/
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/* Driver exported variables. */
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@ -63,24 +70,39 @@ PWMDriver PWMD3;
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/* Driver local variables and types. */
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/*===========================================================================*/
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static const uint8_t pwm_margin_by_prescaler[] = {
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(PWM_GPIOTE_DECISION_TIME + 0) >> 0,
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(PWM_GPIOTE_DECISION_TIME + 1) >> 1,
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(PWM_GPIOTE_DECISION_TIME + 3) >> 2,
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(PWM_GPIOTE_DECISION_TIME + 7) >> 3,
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(PWM_GPIOTE_DECISION_TIME + 15) >> 4,
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(PWM_GPIOTE_DECISION_TIME + 31) >> 5,
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(PWM_GPIOTE_DECISION_TIME + 63) >> 6,
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(PWM_GPIOTE_DECISION_TIME + 127) >> 7,
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(PWM_GPIOTE_DECISION_TIME + 255) >> 8,
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(PWM_GPIOTE_DECISION_TIME + 511) >> 9
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};
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/*===========================================================================*/
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/* Driver local functions. */
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/*===========================================================================*/
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static void pwm_lld_serve_interrupt(PWMDriver *pwmp) {
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// Deal with PWM channels
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uint8_t n;
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for (n = 0 ; n < pwmp->channels ; n++) {
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if (pwmp->timer->EVENTS_COMPARE[n]) {
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pwmp->timer->EVENTS_COMPARE[n] = 0;
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uint8_t channel;
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/* Deal with PWM channels
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*/
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for (channel = 0 ; channel < pwmp->channels ; channel++) {
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if (pwmp->timer->EVENTS_COMPARE[channel]) {
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pwmp->timer->EVENTS_COMPARE[channel] = 0;
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if (pwmp->config->channels[n].callback != NULL) {
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pwmp->config->channels[n].callback(pwmp);
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if (pwmp->config->channels[channel].callback != NULL) {
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pwmp->config->channels[channel].callback(pwmp);
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}
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}
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}
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// Deal with PWM period
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/* Deal with PWM period
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*/
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if (pwmp->timer->EVENTS_COMPARE[pwmp->channels]) {
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pwmp->timer->EVENTS_COMPARE[pwmp->channels] = 0;
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@ -88,7 +110,14 @@ static void pwm_lld_serve_interrupt(PWMDriver *pwmp) {
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pwmp->config->callback(pwmp);
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}
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}
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}
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static inline
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bool pwm_within_safe_margins(PWMDriver *pwmp, uint32_t timer, uint32_t width) {
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const uint32_t margin = pwm_margin_by_prescaler[pwmp->timer->PRESCALER];
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return (width <= margin)
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? ((width <= timer) && (timer < (pwmp->period + width - margin)))
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: ((width <= timer) || (timer < (width - margin)));
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}
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/*===========================================================================*/
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@ -174,47 +203,45 @@ void pwm_lld_init(void) {
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* @notapi
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*/
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void pwm_lld_start(PWMDriver *pwmp) {
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// Prescaler value calculation: ftimer = 16MHz / 2^PRESCALER
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/* Prescaler value calculation: ftimer = 16MHz / 2^PRESCALER */
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uint16_t psc_ratio = NRF5_HFCLK_FREQUENCY / pwmp->config->frequency;
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// Prescaler ratio must be between 1 and 512, and a power of two.
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/* Prescaler ratio must be between 1 and 512, and a power of two. */
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osalDbgAssert(psc_ratio <= 512 && !(psc_ratio & (psc_ratio - 1)),
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"invalid frequency");
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// Prescaler value as a power of 2, must be 0..9
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"invalid frequency");
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/* Prescaler value as a power of 2, must be 0..9 */
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uint32_t psc_value;
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for (psc_value = 0; psc_value < 10; psc_value++)
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if (psc_ratio == (unsigned)(1 << psc_value))
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break;
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if (psc_ratio == (unsigned)(1 << psc_value))
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break;
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// Configure as 16bits timer (only TIMER0 support 32bits)
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/* Configure as 16bits timer (only TIMER0 support 32bits) */
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pwmp->timer->BITMODE = TIMER_BITMODE_BITMODE_16Bit;
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pwmp->timer->MODE = TIMER_MODE_MODE_Timer;
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// With clear shortcuts for period
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/* With clear shortcuts for period */
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pwmp->timer->SHORTS =
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0x1UL << (TIMER_SHORTS_COMPARE0_CLEAR_Pos + pwmp->channels);
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0x1UL << (TIMER_SHORTS_COMPARE0_CLEAR_Pos + pwmp->channels);
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// Disable and reset interrupts for compare events
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/* Disable and reset interrupts for compare events */
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pwmp->timer->INTENCLR = (TIMER_INTENCLR_COMPARE0_Msk |
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TIMER_INTENCLR_COMPARE1_Msk |
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TIMER_INTENCLR_COMPARE2_Msk |
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TIMER_INTENCLR_COMPARE3_Msk );
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TIMER_INTENCLR_COMPARE1_Msk |
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TIMER_INTENCLR_COMPARE2_Msk |
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TIMER_INTENCLR_COMPARE3_Msk );
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pwmp->timer->EVENTS_COMPARE[0] = 0;
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pwmp->timer->EVENTS_COMPARE[1] = 0;
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pwmp->timer->EVENTS_COMPARE[2] = 0;
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pwmp->timer->EVENTS_COMPARE[3] = 0;
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// Set prescaler
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/* Set prescaler */
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pwmp->timer->PRESCALER = psc_value;
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// Set period
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/* Set period */
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pwmp->timer->CC[pwmp->channels] = pwmp->period;
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// Clear everything
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/* Clear everything */
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pwmp->timer->TASKS_CLEAR = 1;
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// Enable interrupt
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/* Enable interrupt */
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#if NRF5_PWM_USE_TIMER0
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if (&PWMD1 == pwmp) {
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nvicEnableVector(TIMER0_IRQn, NRF5_PWM_TIMER0_PRIORITY);
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@ -233,7 +260,7 @@ void pwm_lld_start(PWMDriver *pwmp) {
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}
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#endif
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// Start timer
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/* Start timer */
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pwmp->timer->TASKS_START = 1;
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}
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@ -245,7 +272,7 @@ void pwm_lld_start(PWMDriver *pwmp) {
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* @notapi
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*/
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void pwm_lld_stop(PWMDriver *pwmp) {
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pwmp->timer->TASKS_STOP = 1;
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pwmp->timer->TASKS_SHUTDOWN = 1;
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#if NRF5_PWM_USE_TIMER0
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if (&PWMD1 == pwmp) {
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@ -284,41 +311,81 @@ void pwm_lld_enable_channel(PWMDriver *pwmp,
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pwmcnt_t width) {
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#if NRF5_PWM_USE_GPIOTE_PPI
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const PWMChannelConfig *cfg_channel = &pwmp->config->channels[channel];
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uint32_t outinit;
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switch(cfg_channel->mode & PWM_OUTPUT_MASK) {
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case PWM_OUTPUT_ACTIVE_LOW:
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outinit = GPIOTE_CONFIG_OUTINIT_Low;
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break;
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case PWM_OUTPUT_ACTIVE_HIGH:
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outinit = GPIOTE_CONFIG_OUTINIT_High;
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break;
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case PWM_OUTPUT_DISABLED:
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default:
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goto no_output_config;
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}
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const uint32_t gpio_pin = PAL_PAD(cfg_channel->ioline);
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const uint8_t gpiote_channel = cfg_channel->gpiote_channel;
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const uint8_t *ppi_channel = cfg_channel->ppi_channel;
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const uint32_t polarity = GPIOTE_CONFIG_POLARITY_Toggle;
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uint32_t outinit;
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switch(cfg_channel->mode & PWM_OUTPUT_MASK) {
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case PWM_OUTPUT_ACTIVE_LOW : outinit = GPIOTE_CONFIG_OUTINIT_Low; break;
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case PWM_OUTPUT_ACTIVE_HIGH: outinit = GPIOTE_CONFIG_OUTINIT_High; break;
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case PWM_OUTPUT_DISABLED : /* fall-through */
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default : goto no_output_config;
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}
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// Create GPIO Task
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NRF_GPIOTE->CONFIG[gpiote_channel] = GPIOTE_CONFIG_MODE_Task |
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((gpio_pin << GPIOTE_CONFIG_PSEL_Pos ) & GPIOTE_CONFIG_PSEL_Msk) |
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((polarity << GPIOTE_CONFIG_POLARITY_Pos) & GPIOTE_CONFIG_POLARITY_Msk) |
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((outinit << GPIOTE_CONFIG_OUTINIT_Pos ) & GPIOTE_CONFIG_OUTINIT_Msk);
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/* Deal with corner case: 0% and 100% */
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if ((width <= 0) || (width >= pwmp->period)) {
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/* Disable GPIOTE/PPI task */
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NRF_GPIOTE->CONFIG[gpiote_channel] = GPIOTE_CONFIG_MODE_Disabled;
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NRF_PPI->CHENCLR = ((1 << ppi_channel[0]) | (1 << ppi_channel[1]));
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/* Set Line */
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palWriteLine(cfg_channel->ioline,
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((width <= 0) ^
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((cfg_channel->mode & PWM_OUTPUT_MASK) == PWM_OUTPUT_ACTIVE_HIGH)));
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// Program tasks (one for duty cycle, one for periode)
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NRF_PPI->CH[ppi_channel[0]].EEP =
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/* Really doing PWM */
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} else {
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const uint32_t gpio_pin = PAL_PAD(cfg_channel->ioline);
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const uint32_t polarity = GPIOTE_CONFIG_POLARITY_Toggle;
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/* Program tasks (one for duty cycle, one for periode) */
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NRF_PPI->CH[ppi_channel[0]].EEP =
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(uint32_t)&pwmp->timer->EVENTS_COMPARE[channel];
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NRF_PPI->CH[ppi_channel[0]].TEP =
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NRF_PPI->CH[ppi_channel[0]].TEP =
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(uint32_t)&NRF_GPIOTE->TASKS_OUT[gpiote_channel];
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NRF_PPI->CH[ppi_channel[1]].EEP =
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NRF_PPI->CH[ppi_channel[1]].EEP =
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(uint32_t)&pwmp->timer->EVENTS_COMPARE[pwmp->channels];
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NRF_PPI->CH[ppi_channel[1]].TEP =
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NRF_PPI->CH[ppi_channel[1]].TEP =
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(uint32_t)&NRF_GPIOTE->TASKS_OUT[gpiote_channel];
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NRF_PPI->CHENSET = ((1 << ppi_channel[0]) | (1 << ppi_channel[1]));
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NRF_PPI->CHENSET = ((1 << ppi_channel[0]) | (1 << ppi_channel[1]));
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/* Something Old, something New */
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const uint32_t old_width = pwmp->timer->CC[channel];
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const uint32_t new_width = width;
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/* Check GPIOTE state */
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const bool gpiote = (NRF_GPIOTE->CONFIG[gpiote_channel] &
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GPIOTE_CONFIG_MODE_Msk) != GPIOTE_CONFIG_MODE_Disabled;
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/* GPIOTE is currently running */
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if (gpiote) {
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uint32_t current;
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while (true) {
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pwmp->timer->TASKS_CAPTURE[PWM_GPIOTE_PPI_CC] = 1;
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current = pwmp->timer->CC[PWM_GPIOTE_PPI_CC];
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if (pwm_within_safe_margins(pwmp, current, old_width) &&
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pwm_within_safe_margins(pwmp, current, new_width))
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break;
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}
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if (((old_width <= current) && (current < new_width)) ||
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((new_width <= current) && (current < old_width))) {
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NRF_GPIOTE->TASKS_OUT[gpiote_channel] = 1;
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}
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/* GPIOTE need to be restarted */
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} else {
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/* Create GPIO Task */
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NRF_GPIOTE->CONFIG[gpiote_channel] =
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(GPIOTE_CONFIG_MODE_Task << GPIOTE_CONFIG_MODE_Pos) |
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((gpio_pin << GPIOTE_CONFIG_PSEL_Pos ) & GPIOTE_CONFIG_PSEL_Msk )|
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((polarity << GPIOTE_CONFIG_POLARITY_Pos) & GPIOTE_CONFIG_POLARITY_Msk)|
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((outinit << GPIOTE_CONFIG_OUTINIT_Pos ) & GPIOTE_CONFIG_OUTINIT_Msk );
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pwmp->timer->TASKS_CAPTURE[PWM_GPIOTE_PPI_CC] = 1;
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if (pwmp->timer->CC[PWM_GPIOTE_PPI_CC] > width)
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NRF_GPIOTE->TASKS_OUT[gpiote_channel] = 1;
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}
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}
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no_output_config:
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#endif
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@ -369,7 +436,7 @@ void pwm_lld_disable_channel(PWMDriver *pwmp, pwmchannel_t channel) {
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*/
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void pwm_lld_enable_periodic_notification(PWMDriver *pwmp) {
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pwmp->timer->INTENSET =
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0x1UL << (TIMER_INTENSET_COMPARE0_Pos + pwmp->channels);
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0x1UL << (TIMER_INTENSET_COMPARE0_Pos + pwmp->channels);
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}
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/**
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@ -383,7 +450,7 @@ void pwm_lld_enable_periodic_notification(PWMDriver *pwmp) {
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*/
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void pwm_lld_disable_periodic_notification(PWMDriver *pwmp) {
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pwmp->timer->INTENCLR =
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0x1UL << (TIMER_INTENCLR_COMPARE0_Pos + pwmp->channels);
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0x1UL << (TIMER_INTENCLR_COMPARE0_Pos + pwmp->channels);
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}
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/**
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@ -400,7 +467,7 @@ void pwm_lld_disable_periodic_notification(PWMDriver *pwmp) {
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void pwm_lld_enable_channel_notification(PWMDriver *pwmp,
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pwmchannel_t channel) {
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pwmp->timer->INTENSET =
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0x1UL << (TIMER_INTENSET_COMPARE0_Pos + channel);
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0x1UL << (TIMER_INTENSET_COMPARE0_Pos + channel);
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}
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/**
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@ -409,15 +476,15 @@ void pwm_lld_enable_channel_notification(PWMDriver *pwmp,
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* @pre The channel must have been activated using @p pwmEnableChannel().
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* @note If the notification is already disabled then the call has no effect.
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*
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* @param[in] pwmp pointer to a @p PWMDriver object
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* @param[in] channel PWM channel identifier (0...channels-1)
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* @param[in] pwmp pointer to a @p PWMDriver object
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* @param[in] channel PWM channel identifier (0...channels-1)
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*
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* @notapi
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*/
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void pwm_lld_disable_channel_notification(PWMDriver *pwmp,
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pwmchannel_t channel) {
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pwmchannel_t channel) {
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pwmp->timer->INTENCLR =
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0x1UL << (TIMER_INTENCLR_COMPARE0_Pos + channel);
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0x1UL << (TIMER_INTENCLR_COMPARE0_Pos + channel);
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}
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#endif /* HAL_USE_PWM */
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@ -34,8 +34,11 @@
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/**
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* @brief Number of PWM channels per PWM driver.
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*/
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#if NRF5_PWM_USE_GPIOTE_PPI
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#define PWM_CHANNELS 2
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#else
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#define PWM_CHANNELS 3
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#endif
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#define PWM_FREQUENCY_16MHZ 16000000 /** @brief 16MHz */
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#define PWM_FREQUENCY_8MHZ 8000000 /** @brief 8MHz */
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@ -103,7 +106,7 @@
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* @brief Allow driver to use GPIOTE/PPI to control PAL line
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*/
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#if !defined(NRF5_PWM_USE_GPIOTE_PPI)
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#define NRF5_PWM_USE_GPIOTE_PPI FALSE
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#define NRF5_PWM_USE_GPIOTE_PPI TRUE
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#endif
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/** @} */
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@ -177,6 +180,7 @@ typedef struct {
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pwmcallback_t callback;
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/* End of the mandatory fields.*/
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#if NRF5_PWM_USE_GPIOTE_PPI || defined(__DOXYGEN__)
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/**
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* @brief PAL line to toggle.
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* @note Only used if mode is PWM_OUTPUT_HIGH or PWM_OUTPUT_LOW.
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@ -186,17 +190,14 @@ typedef struct {
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*/
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ioline_t ioline;
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#if NRF5_PWM_USE_GPIOTE_PPI || defined(__DOXYGEN__)
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/**
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* @brief Unique GPIOTE channel to use. (1 channel)
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* @note Only used if mode is PWM_OUTPUT_HIGH or PWM_OUTPUT_LOW.
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* @note Only 4 GPIOTE channels are available on nRF51.
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*/
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uint8_t gpiote_channel;
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/**
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* @brief Unique PPI channels to use. (2 channels)
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* @note Only used if mode is PWM_OUTPUT_HIGH or PWM_OUTPUT_LOW.
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* @note Only 16 PPI channels are available on nRF51
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* (When Softdevice is enabled, only channels 0-7 are available)
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*/
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