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Dynamic prescaler adjustment, adjust pulse resolution

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This commit is contained in:
Hierophect 2019-10-29 17:17:26 -04:00
parent 4de5a33a43
commit 6b0cb87cbf
1 changed files with 37 additions and 32 deletions
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69
ports/stm32f4/common-hal/pulseio/PWMOut.c
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@ -35,7 +35,7 @@
#include "stm32f4xx_hal.h" #include "stm32f4xx_hal.h"
#include "common-hal/microcontroller/Pin.h" #include "common-hal/microcontroller/Pin.h"
#define PWM_MAX_FREQ 6000000 #define PULSE_RESOLUTION 256 //8 bit
#define ALL_CLOCKS 0xFFFF #define ALL_CLOCKS 0xFFFF
STATIC uint8_t reserved_tim[TIM_BANK_ARRAY_LEN]; STATIC uint8_t reserved_tim[TIM_BANK_ARRAY_LEN];
@ -45,8 +45,6 @@ STATIC bool never_reset_tim[TIM_BANK_ARRAY_LEN];
STATIC void tim_clock_enable(uint16_t mask); STATIC void tim_clock_enable(uint16_t mask);
STATIC void tim_clock_disable(uint16_t mask); STATIC void tim_clock_disable(uint16_t mask);
RCC->CFGR & RCC_CFGR_PPRE1
// Get the frequency (in Hz) of the source clock for the given timer. // Get the frequency (in Hz) of the source clock for the given timer.
// On STM32F405/407/415/417 there are 2 cases for how the clock freq is set. // On STM32F405/407/415/417 there are 2 cases for how the clock freq is set.
// If the APB prescaler is 1, then the timer clock is equal to its respective // If the APB prescaler is 1, then the timer clock is equal to its respective
@ -107,10 +105,6 @@ pwmout_result_t common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
uint16_t duty, uint16_t duty,
uint32_t frequency, uint32_t frequency,
bool variable_frequency) { bool variable_frequency) {
if (frequency == 0 || frequency > 6000000) {
mp_raise_ValueError(translate("Invalid frequency supplied"));
}
TIM_TypeDef * TIMx; TIM_TypeDef * TIMx;
uint8_t tim_num = sizeof(mcu_tim_pin_list)/sizeof(*mcu_tim_pin_list); uint8_t tim_num = sizeof(mcu_tim_pin_list)/sizeof(*mcu_tim_pin_list);
bool tim_chan_taken = false; bool tim_chan_taken = false;
@ -189,19 +183,25 @@ pwmout_result_t common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
} }
uint32_t source_freq = timer_get_source_freq(self->tim->tim_index); uint32_t source_freq = timer_get_source_freq(self->tim->tim_index);
uint32_t period = PWM_MAX_FREQ/frequency; if (frequency == 0 || frequency * PULSE_RESOLUTION > (source_freq)) {
mp_raise_ValueError(translate("Invalid frequency supplied"));
}
uint32_t prescaler = source_freq/(frequency*PULSE_RESOLUTION);
uint32_t period = PULSE_RESOLUTION;
uint32_t input = (duty*PULSE_RESOLUTION)/65535;
//Used for Debugging //Used for Debugging
// mp_printf(&mp_plat_print, "SysCoreClock: %d\n", SystemCoreClock); mp_printf(&mp_plat_print, "Duty:%d, Pulses:%d\n", duty,input);
// mp_printf(&mp_plat_print, "Source Freq: %d\n", source_freq); mp_printf(&mp_plat_print, "SysCoreClock: %d\n", SystemCoreClock);
// mp_printf(&mp_plat_print, "Timer Freq: %d\n", source_freq/(source_freq / PWM_MAX_FREQ)); mp_printf(&mp_plat_print, "Source Freq: %d\n", source_freq);
// mp_printf(&mp_plat_print, "Actual Freq: %d\n", (source_freq/(source_freq / PWM_MAX_FREQ))/period); mp_printf(&mp_plat_print, "Prescaler %d, Timer Freq: %d\n", prescaler, source_freq/prescaler);
// mp_printf(&mp_plat_print, "Duty: %d\n", duty); mp_printf(&mp_plat_print, "Output Freq: %d\n", (source_freq/prescaler)/period);
// mp_printf(&mp_plat_print, "TIM#:%d CH:%d ALTF:%d\n", self->tim->tim_index, self->tim->channel_index, self->tim->altfn_index); mp_printf(&mp_plat_print, "Duty: %d\n", duty);
mp_printf(&mp_plat_print, "TIM#:%d CH:%d ALTF:%d\n", self->tim->tim_index, self->tim->channel_index, self->tim->altfn_index);
//Timer init //Timer init
self->handle.Instance = TIMx; self->handle.Instance = TIMx;
self->handle.Init.Period = period - 1; self->handle.Init.Period = period - 1;
self->handle.Init.Prescaler = (source_freq / PWM_MAX_FREQ) - 1; // TIM runs at ~6MHz self->handle.Init.Prescaler = prescaler - 1;
self->handle.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1; self->handle.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
self->handle.Init.CounterMode = TIM_COUNTERMODE_UP; self->handle.Init.CounterMode = TIM_COUNTERMODE_UP;
self->handle.Init.RepetitionCounter = 0; self->handle.Init.RepetitionCounter = 0;
@ -209,23 +209,23 @@ pwmout_result_t common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
//only run init if this is the first instance of this timer //only run init if this is the first instance of this timer
if (first_time_setup) { if (first_time_setup) {
if (HAL_TIM_PWM_Init(&self->handle) != HAL_OK) { if (HAL_TIM_PWM_Init(&self->handle) != HAL_OK) {
mp_raise_ValueError(translate("Timer Init Error")); mp_raise_ValueError(translate("Could not initialize timer"));
} }
} }
//Channel/PWM init //Channel/PWM init
self->chan_handle.OCMode = TIM_OCMODE_PWM1; self->chan_handle.OCMode = TIM_OCMODE_PWM1;
self->chan_handle.Pulse = (period*duty)/100 - 1; self->chan_handle.Pulse = input; //-1?
self->chan_handle.OCPolarity = TIM_OCPOLARITY_LOW; self->chan_handle.OCPolarity = TIM_OCPOLARITY_LOW;
self->chan_handle.OCFastMode = TIM_OCFAST_DISABLE; self->chan_handle.OCFastMode = TIM_OCFAST_DISABLE;
self->chan_handle.OCNPolarity = TIM_OCNPOLARITY_LOW; // needed for TIM1 and TIM8 self->chan_handle.OCNPolarity = TIM_OCNPOLARITY_LOW; // needed for TIM1 and TIM8
self->chan_handle.OCIdleState = TIM_OCIDLESTATE_SET; // needed for TIM1 and TIM8 self->chan_handle.OCIdleState = TIM_OCIDLESTATE_SET; // needed for TIM1 and TIM8
self->chan_handle.OCNIdleState = TIM_OCNIDLESTATE_SET; // needed for TIM1 and TIM8 self->chan_handle.OCNIdleState = TIM_OCNIDLESTATE_SET; // needed for TIM1 and TIM8
if (HAL_TIM_PWM_ConfigChannel(&self->handle, &self->chan_handle, self->channel) != HAL_OK) { if (HAL_TIM_PWM_ConfigChannel(&self->handle, &self->chan_handle, self->channel) != HAL_OK) {
mp_raise_ValueError(translate("Channel Init Error")); mp_raise_ValueError(translate("Could not initialize channel"));
} }
if (HAL_TIM_PWM_Start(&self->handle, self->channel) != HAL_OK) { if (HAL_TIM_PWM_Start(&self->handle, self->channel) != HAL_OK) {
mp_raise_ValueError(translate("Error starting PWM")); mp_raise_ValueError(translate("Could not start PWM"));
} }
self->variable_frequency = variable_frequency; self->variable_frequency = variable_frequency;
@ -261,14 +261,12 @@ void common_hal_pulseio_pwmout_deinit(pulseio_pwmout_obj_t* self) {
} }
void common_hal_pulseio_pwmout_set_duty_cycle(pulseio_pwmout_obj_t* self, uint16_t duty_cycle) { void common_hal_pulseio_pwmout_set_duty_cycle(pulseio_pwmout_obj_t* self, uint16_t duty_cycle) {
uint16_t duty = duty_cycle/655; uint32_t input = (duty_cycle*PULSE_RESOLUTION)/65535;
uint32_t period = PWM_MAX_FREQ/self->frequency;
uint32_t input = (period*duty)/100;
//Used for debugging //Used for debugging
//mp_printf(&mp_plat_print, "duty_cycle %d, Duty: %d, Input %d\n", duty_cycle, duty, input); //mp_printf(&mp_plat_print, "duty_cycle %d, Duty: %d, Input %d\n", duty_cycle, duty, input);
__HAL_TIM_SET_COMPARE(&self->handle, self->channel, input); __HAL_TIM_SET_COMPARE(&self->handle, self->channel, input);
self->duty_cycle = duty; self->duty_cycle = duty_cycle;
} }
uint16_t common_hal_pulseio_pwmout_get_duty_cycle(pulseio_pwmout_obj_t* self) { uint16_t common_hal_pulseio_pwmout_get_duty_cycle(pulseio_pwmout_obj_t* self) {
@ -276,31 +274,38 @@ uint16_t common_hal_pulseio_pwmout_get_duty_cycle(pulseio_pwmout_obj_t* self) {
} }
void common_hal_pulseio_pwmout_set_frequency(pulseio_pwmout_obj_t* self, uint32_t frequency) { void common_hal_pulseio_pwmout_set_frequency(pulseio_pwmout_obj_t* self, uint32_t frequency) {
if (frequency == 0 || frequency > 6000000) { //don't halt setup for the same frequency
mp_raise_ValueError(translate("Invalid PWM frequency"));
}
if (frequency == self->frequency) return; if (frequency == self->frequency) return;
//calculate new values
uint32_t source_freq = timer_get_source_freq(self->tim->tim_index); uint32_t source_freq = timer_get_source_freq(self->tim->tim_index);
uint32_t period = PWM_MAX_FREQ/frequency; if (frequency == 0 || frequency*PULSE_RESOLUTION > (source_freq)) {
mp_raise_ValueError(translate("Invalid frequency supplied"));
}
uint32_t prescaler = source_freq/(frequency*PULSE_RESOLUTION);
uint32_t period = PULSE_RESOLUTION;
//this shouldn't ever exceed 0xffff*0xffff = 0xfffe0001, so it won't integer overflow.
uint32_t input = (self->duty_cycle*PULSE_RESOLUTION)/65535;
//shut down //shut down
HAL_TIM_PWM_Stop(&self->handle, self->channel); HAL_TIM_PWM_Stop(&self->handle, self->channel);
//Only change altered values //Only change altered values
self->handle.Init.Period = period - 1; self->handle.Init.Period = period - 1;
self->handle.Init.Prescaler = (source_freq / PWM_MAX_FREQ) - 1; // TIM runs at ~6MHz self->handle.Init.Prescaler = prescaler - 1;
//restart everything, adjusting for new speed //restart everything, adjusting for new speed
if (HAL_TIM_PWM_Init(&self->handle) != HAL_OK) { if (HAL_TIM_PWM_Init(&self->handle) != HAL_OK) {
mp_raise_ValueError(translate("Timer Re-Init Error")); mp_raise_ValueError(translate("Could not re-init timer"));
} }
self->chan_handle.Pulse = (period*self->duty_cycle)/100 - 1;
self->chan_handle.Pulse = input;
if (HAL_TIM_PWM_ConfigChannel(&self->handle, &self->chan_handle, self->channel) != HAL_OK) { if (HAL_TIM_PWM_ConfigChannel(&self->handle, &self->chan_handle, self->channel) != HAL_OK) {
mp_raise_ValueError(translate("Channel Re-Init Error")); mp_raise_ValueError(translate("Could not re-init channel"));
} }
if (HAL_TIM_PWM_Start(&self->handle, self->channel) != HAL_OK) { if (HAL_TIM_PWM_Start(&self->handle, self->channel) != HAL_OK) {
mp_raise_ValueError(translate("Error restarting PWM")); mp_raise_ValueError(translate("Could not restart PWM"));
} }
tim_frequencies[self->tim->tim_index-1] = frequency; tim_frequencies[self->tim->tim_index-1] = frequency;