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mimxrt/machine_pwm: Fix a few inconsistencies with PWM output.

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Changes in this commit:
- When setting PWM parameters of a FLEXPWM AB channel twice within a PWM
  cycle, the second setting was ignored. Now the second setting persists.
- With `duty_u16(0)` a FLEXPWM X channel was set to high impedance.  Now it
  is set to low impedance with value 0 for `invert=False`, and 1 for
  `invert=True`.
- The align parameter requires a duty rate and frequency to be set.  Align
  will now be ignored if freq or duty are missing.

Signed-off-by: robert-hh <robert@hammelrath.com>
This commit is contained in:
robert-hh 2024-11-06 20:26:27 +01:00 committed by Damien George
parent 898407defb
commit e2532e0f72
2 changed files with 28 additions and 9 deletions
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6
ports/mimxrt/hal/pwm_backport.c
View file

@ -110,12 +110,8 @@ void PWM_SetupPwmx_u16(PWM_Type *base, pwm_submodule_t subModule,
base->SM[subModule].OCTRL = (base->SM[subModule].OCTRL & ~PWM_OCTRL_POLX_MASK) | PWM_OCTRL_POLX(!invert);
// Switch the output on or off.
if (duty_cycle == 0) {
base->OUTEN &= ~(1U << subModule);
} else {
// Enable PWM output
base->OUTEN |= (1U << subModule);
}
}
#ifdef FSL_FEATURE_SOC_TMR_COUNT

29
ports/mimxrt/machine_pwm.c
View file

@ -45,6 +45,8 @@
typedef struct _machine_pwm_obj_t {
mp_obj_base_t base;
PWM_Type *instance;
const machine_pin_obj_t *pwm_pin;
const machine_pin_af_obj_t *pwm_pin_af_obj;
bool is_flexpwm;
uint8_t complementary;
uint8_t module;
@ -255,6 +257,8 @@ static void configure_flexpwm(machine_pwm_obj_t *self) {
PWM_SetupFaultDisableMap(self->instance, self->submodule, self->channel2, kPWM_faultchannel_1, 0);
}
// clear the load okay bit for the submodules in case there is a pending load
PWM_SetPwmLdok(self->instance, 1 << self->submodule, false);
if (self->channel1 != kPWM_PwmX) { // Only for A/B channels
// Initialize the channel parameters
pwmSignal.pwmChannel = self->channel1;
@ -283,6 +287,17 @@ static void configure_flexpwm(machine_pwm_obj_t *self) {
self->instance->SM[self->submodule].CTRL &= ~(PWM_CTRL_DBLEN_MASK | PWM_CTRL_SPLIT_MASK);
}
} else {
if (self->duty_u16 == 0) {
// For duty_u16 == 0 just set the output to GPIO mode
if (self->invert) {
mp_hal_pin_high(self->pwm_pin);
} else {
mp_hal_pin_low(self->pwm_pin);
}
IOMUXC_SetPinMux(self->pwm_pin->muxRegister, PIN_AF_MODE_ALT5, 0, 0, 0, 0U);
} else {
IOMUXC_SetPinMux(self->pwm_pin->muxRegister, self->pwm_pin_af_obj->af_mode, 0, 0, 0, 0U);
}
PWM_SetupPwmx_u16(self->instance, self->submodule, self->freq, self->duty_u16,
self->invert, pwmSourceClockInHz);
if (self->xor) {
@ -408,12 +423,16 @@ static void mp_machine_pwm_init_helper(machine_pwm_obj_t *self,
}
self->center = center;
} else { // Use alignment setting shortcut
if (args[ARG_align].u_int >= 0) {
uint32_t duty = self->duty_u16;
if (duty == VALUE_NOT_SET && self->duty_ns != VALUE_NOT_SET) {
duty = duty_ns_to_duty_u16(self->freq, self->duty_ns);
}
if (args[ARG_align].u_int >= 0 && duty != VALUE_NOT_SET && self->freq != VALUE_NOT_SET) {
uint8_t align = args[ARG_align].u_int & 3; // limit to 0..3
if (align == PWM_BEGIN) {
self->center = self->duty_u16 / 2;
self->center = duty / 2;
} else if (align == PWM_END) {
self->center = PWM_FULL_SCALE - self->duty_u16 / 2;
self->center = PWM_FULL_SCALE - duty / 2;
} else {
self->center = 32768; // Default value: mid.
}
@ -515,6 +534,8 @@ static mp_obj_t mp_machine_pwm_make_new(const mp_obj_type_t *type, size_t n_args
// Create and populate the PWM object.
machine_pwm_obj_t *self = mp_obj_malloc(machine_pwm_obj_t, &machine_pwm_type);
self->pwm_pin = pin1;
self->pwm_pin_af_obj = af_obj1;
self->is_flexpwm = is_flexpwm;
self->instance = af_obj1->instance;
self->module = module;
@ -534,6 +555,8 @@ static mp_obj_t mp_machine_pwm_make_new(const mp_obj_type_t *type, size_t n_args
// Initialize the Pin(s).
CLOCK_EnableClock(kCLOCK_Iomuxc); // just in case it was not set yet
// Configure PWMX channels to pin output mode to be prepared for duty_u16 == 0.
mp_hal_pin_output(pin1);
IOMUXC_SetPinMux(pin1->muxRegister, af_obj1->af_mode, af_obj1->input_register, af_obj1->input_daisy,
pin1->configRegister, 0U);
IOMUXC_SetPinConfig(pin1->muxRegister, af_obj1->af_mode, af_obj1->input_register, af_obj1->input_daisy,