8000 esp32/machine_pwm: Always set the duty cycle when setting the frequency. · micropython/micropython@55a0125 · GitHub
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robert-hhdpgeorge
robert-hh
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dpgeorge
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esp32/machine_pwm: Always set the duty cycle when setting the frequency.
If setting the frequency to a value used already by an existing timer, this timer will be used. But still, the duty cycle for that channel may have to be changed. Fixes issues #8306 and #8345.
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‎ports/esp32/machine_pwm.c

100755100644
Lines changed: 35 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -74,7 +74,8 @@ STATIC ledc_timer_config_t timers[PWM_TIMER_MAX];
7474
// Params for PWM operation
7575
// 5khz is default frequency
7676
#define PWM_FREQ (5000)
77-
// default 10-bit resolution (compatible with esp8266 PWM)
77+
78+
// 10-bit resolution (compatible with esp8266 PWM)
7879
#define PWM_RES_10_BIT (LEDC_TIMER_10_BIT)
7980

8081
// Maximum duty value on 10-bit resolution
@@ -84,15 +85,17 @@ STATIC ledc_timer_config_t timers[PWM_TIMER_MAX];
8485
// duty_u16() and duty_ns() use 16-bit resolution or less
8586

8687
// Possible highest resolution in device
87-
#if CONFIG_IDF_TARGET_ESP32
88-
#define HIGHEST_PWM_RES (LEDC_TIMER_16_BIT) // 20 bit for ESP32, but 16 bit is used
88+
#if (LEDC_TIMER_BIT_MAX - 1) < LEDC_TIMER_16_BIT
89+
#define HIGHEST_PWM_RES (LEDC_TIMER_BIT_MAX - 1)
8990
#else
90-
#define HIGHEST_PWM_RES (LEDC_TIMER_BIT_MAX - 1) // 14 bit is used
91+
#define HIGHEST_PWM_RES (LEDC_TIMER_16_BIT) // 20 bit for ESP32, but 16 bit is used
9192
#endif
9293
// Duty resolution of user interface in `duty_u16()` and `duty_u16` parameter in constructor/initializer
9394
#define UI_RES_16_BIT (16)
9495
// Maximum duty value on highest user interface resolution
9596
#define UI_MAX_DUTY ((1 << UI_RES_16_BIT) - 1)
97+
// How much to shift from the HIGHEST_PWM_RES duty resolution to the user interface duty resolution UI_RES_16_BIT
98+
#define UI_RES_SHIFT (UI_RES_16_BIT - HIGHEST_PWM_RES) // 0 for ESP32, 2 for S2, S3, C3
9699

97100
// If the PWM frequency is less than EMPIRIC_FREQ, then LEDC_REF_CLK_HZ(1 MHz) source is used, else LEDC_APB_CLK_HZ(80 MHz) source is used
98101
#define EMPIRIC_FREQ (10) // Hz
@@ -108,7 +111,7 @@ typedef struct _machine_pwm_obj_t {
108111
int mode;
109112
int channel;
110113
int timer;
111-
int duty_x; // PWM_RES_10_BIT if duty(), UI_RES_16_BIT if duty_u16(), -UI_RES_16_BIT if duty_ns()
114+
int duty_x; // PWM_RES_10_BIT if duty(), HIGHEST_PWM_RES if duty_u16(), -HIGHEST_PWM_RES if duty_ns()
112115
int duty_u10; // stored values from previous duty setters
113116
int duty_u16; // - / -
114117
int duty_ns; // - / -
@@ -237,7 +240,6 @@ STATIC void set_freq(machine_pwm_obj_t *self, unsigned int freq, ledc_timer_conf
237240
}
238241

239242
// Configure the new resolution and frequency
240-
unsigned int save_duty_resolution = timer->duty_resolution;
241243
timer->duty_resolution = res;
242244
timer->freq_hz = freq;
243245
timer->clk_cfg = LEDC_USE_APB_CLK;
@@ -258,17 +260,15 @@ STATIC void set_freq(machine_pwm_obj_t *self, unsigned int freq, ledc_timer_conf
258260
if (self->mode == LEDC_LOW_SPEED_MODE) {
259261
check_esp_err(ledc_timer_rst(self->mode, self->timer));
260262
}
263+
}
261264

262-
// Save the same duty cycle when frequency is changed
263-
if (save_duty_resolution != timer->duty_resolution) {
264-
if (self->duty_x == UI_RES_16_BIT) {
265-
set_duty_u16(self, self->duty_u16);
266-
} else if (self->duty_x == PWM_RES_10_BIT) {
267-
set_duty_u10(self, self->duty_u10);
268-
} else if (self->duty_x == -UI_RES_16_BIT) {
269-
set_duty_ns(self, self->duty_ns);
270-
}
271-
}
265+
// Save the same duty cycle when frequency is changed
266+
if (self->duty_x == HIGHEST_PWM_RES) {
267+
set_duty_u16(self, self->duty_u16);
268+
} else if (self->duty_x == PWM_RES_10_BIT) {
269+
set_duty_u10(self, self->duty_u10);
270+
} else if (self->duty_x == -HIGHEST_PWM_RES) {
271+
set_duty_ns(self, self->duty_ns);
272272
}
273273
}
274274

@@ -293,11 +293,18 @@ STATIC int duty_to_ns(machine_pwm_obj_t *self, int duty) {
293293
#define get_duty_raw(self) ledc_get_duty(self->mode, self->channel)
294294

295295
STATIC uint32_t get_duty_u16(machine_pwm_obj_t *self) {
296-
return ledc_get_duty(self->mode, self->channel) << (UI_RES_16_BIT - timers[TIMER_IDX(self->mode, self->timer)].duty_resolution);
296+
int resolution = timers[TIMER_IDX(self->mode, self->timer)].duty_resolution;
297+
int duty = ledc_get_duty(self->mode, self->channel);
298+
if (resolution <= UI_RES_16_BIT) {
299+
duty <<= (UI_RES_16_BIT - resolution);
300+
} else {
301+
duty >>= (resolution - UI_RES_16_BIT);
302+
}
303+
return duty;
297304
}
298305

299306
STATIC uint32_t get_duty_u10(machine_pwm_obj_t *self) {
300-
return get_duty_u16(self) >> (UI_RES_16_BIT - LEDC_TIMER_10_BIT);
307+
return get_duty_u16(self) >> 6; // Scale down from 16 bit to 10 bit resolution
301308
}
302309

303310
STATIC uint32_t get_duty_ns(machine_pwm_obj_t *self) {
@@ -309,7 +316,12 @@ STATIC void set_duty_u16(machine_pwm_obj_t *self, int duty) {
309316
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("duty_u16 must be from 0 to %d"), UI_MAX_DUTY);
310317
}
311318
ledc_timer_config_t timer = timers[TIMER_IDX(self->mode, self->timer)];
312-
int channel_duty = duty >> (UI_RES_16_BIT - timer.duty_resolution);
319+
int channel_duty;
320+
if (timer.duty_resolution <= UI_RES_16_BIT) {
321+
channel_duty = duty >> (UI_RES_16_BIT - timer.duty_resolution);
322+
} else {
323+
channel_duty = duty << (timer.duty_resolution - UI_RES_16_BIT);
324+
}
313325
int max_duty = (1 << timer.duty_resolution) - 1;
314326
if (channel_duty < 0) {
315327
channel_duty = 0;
@@ -333,15 +345,15 @@ STATIC void set_duty_u16(machine_pwm_obj_t *self, int duty) {
333345
}
334346
*/
335347

336-
self->duty_x = UI_RES_16_BIT;
348+
self->duty_x = HIGHEST_PWM_RES;
337349
self->duty_u16 = duty;
338350
}
339351

340352
STATIC void set_duty_u10(machine_pwm_obj_t *self, int duty) {
341353
if ((duty < 0) || (duty > MAX_DUTY_U10)) {
342354
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("duty must be from 0 to %u"), MAX_DUTY_U10);
343355
}
344-
set_duty_u16(self, duty << (UI_RES_16_BIT - LEDC_TIMER_10_BIT));
356+
set_duty_u16(self, duty << (UI_RES_16_BIT - PWM_RES_10_BIT));
345357
self->duty_x = PWM_RES_10_BIT;
346358
self->duty_u10 = duty;
347359
}
@@ -351,7 +363,7 @@ STATIC void set_duty_ns(machine_pwm_obj_t *self, int ns) {
351363
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("duty_ns must be from 0 to %d ns"), duty_to_ns(self, UI_MAX_DUTY));
352364
}
353365
set_duty_u16(self, ns_to_duty(self, ns));
354-
self->duty_x = -UI_RES_16_BIT;
366+
self->duty_x = -HIGHEST_PWM_RES;
355367
self->duty_ns = ns;
356368
}
357369

@@ -424,7 +436,7 @@ STATIC void mp_machine_pwm_print(const mp_print_t *print, mp_obj_t self_in, mp_p
424436

425437
if (self->duty_x == PWM_RES_10_BIT) {
426438
mp_printf(print, ", duty=%d", get_duty_u10(self));
427-
} else if (self->duty_x == -UI_RES_16_BIT) {
439+
} else if (self->duty_x == -HIGHEST_PWM_RES) {
428440
mp_printf(print, ", duty_ns=%d", get_duty_ns(self));
429441
} else {
430442
mp_printf(print, ", duty_u16=%d", get_duty_u16(self));

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