jepler/circuitpython
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

esp32/machine_pwm: Use IDF functions to calculate resolution correctly.

Browse source 
This commit fixes PWM configuration across C3, C6, S2 and S3 chips, which
was broken by 6d799378ba.  Without this fix
the PWM frequency is limited to a maximum of 2446Hz (on S2 at least).

Signed-off-by: Andrew Leech <andrew@alelec.net>
This commit is contained in:
Andrew Leech 2024-10-27 14:51:37 +11:00 committed by Damien George
parent 86c71a0307
commit 548babf8a0
1 changed files with 16 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

50
ports/esp32/machine_pwm.c
View file

@ -34,6 +34,7 @@
#include "py/mphal.h"
#include "driver/ledc.h"
#include "esp_err.h"
#include "esp_clk_tree.h"
#include "soc/gpio_sig_map.h"
#define PWM_DBG(...)
@ -209,51 +210,32 @@ static void configure_channel(machine_pwm_obj_t *self) {
static void set_freq(machine_pwm_obj_t *self, unsigned int freq, ledc_timer_config_t *timer) {
if (freq != timer->freq_hz) {
// Find the highest bit resolution for the requested frequency
unsigned int i = APB_CLK_FREQ; // 80 MHz
#if SOC_LEDC_SUPPORT_REF_TICK
if (freq < EMPIRIC_FREQ) {
i = REF_CLK_FREQ; // 1 MHz
}
#endif
int divider = (i + freq / 2) / freq; // rounded
if (divider == 0) {
divider = 1;
}
float f = (float)i / divider; // actual frequency
if (f <= 1.0) {
f = 1.0;
}
i = (unsigned int)roundf((float)i / f);
unsigned int res = 0;
for (; i > 1; i >>= 1) {
++res;
}
if (res == 0) {
res = 1;
} else if (res > HIGHEST_PWM_RES) {
// Limit resolution to HIGHEST_PWM_RES to match units of our duty
res = HIGHEST_PWM_RES;
}
// Configure the new resolution and frequency
timer->duty_resolution = res;
// Configure the new frequency and resolution
timer->freq_hz = freq;
#if SOC_LEDC_SUPPORT_XTAL_CLOCK
#if SOC_LEDC_SUPPORT_PLL_DIV_CLOCK
timer->clk_cfg = LEDC_USE_PLL_DIV_CLK;
#elif SOC_LEDC_SUPPORT_APB_CLOCK
timer->clk_cfg = LEDC_USE_APB_CLK;
#elif SOC_LEDC_SUPPORT_XTAL_CLOCK
timer->clk_cfg = LEDC_USE_XTAL_CLK;
#else
timer->clk_cfg = LEDC_USE_APB_CLK;
#error No supported PWM / LEDC clocks.
#endif
#if SOC_LEDC_SUPPORT_REF_TICK
if (freq < EMPIRIC_FREQ) {
timer->clk_cfg = LEDC_USE_REF_TICK;
}
#endif
uint32_t src_clk_freq = 0;
esp_err_t err = esp_clk_tree_src_get_freq_hz(timer->clk_cfg, ESP_CLK_TREE_SRC_FREQ_PRECISION_CACHED, &src_clk_freq);
if (err != ESP_OK) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("unable to query source clock frequency %d"), (int)timer->clk_cfg);
}
timer->duty_resolution = ledc_find_suitable_duty_resolution(src_clk_freq, timer->freq_hz);
// Set frequency
esp_err_t err = ledc_timer_config(timer);
err = ledc_timer_config(timer);
if (err != ESP_OK) {
if (err == ESP_FAIL) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("unreachable frequency %d"), freq);