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feat(ledc): add ledc_find_suitable_duty_resolution helper function

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Helper function to find the maximum possible duty resolution in bits
for ledc_timer_config()

Merges https://github.com/espressif/esp-idf/pull/11810
This commit is contained in:
IhorNehrutsa
2023-10-09 12:46:46 +08:00
committed by Song Ruo Jing
parent fbc31c8f15
commit 9ced54699e
4 changed files with 49 additions and 4 deletions
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components/driver/ledc/ledc.c
+32 -3
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@@ -4,6 +4,7 @@
* SPDX-License-Identifier: Apache-2.0
*/
#include <string.h>
#include <sys/param.h>
#include "esp_types.h"
#include "freertos/FreeRTOS.h"
#include "freertos/semphr.h"
@@ -332,9 +333,9 @@ static inline uint32_t ledc_calculate_divisor(uint32_t src_clk_freq, int freq_hz
* high.
*
* NOTE: We are also going to round up the value when necessary, thanks to:
* (freq_hz * precision) / 2
* (freq_hz * precision / 2)
*/
return ( ( (uint64_t) src_clk_freq << LEDC_LL_FRACTIONAL_BITS ) + ((freq_hz * precision) / 2 ) )
return ( ( (uint64_t) src_clk_freq << LEDC_LL_FRACTIONAL_BITS ) + freq_hz * precision / 2 )
/ (freq_hz * precision);
}
@@ -849,7 +850,35 @@ uint32_t ledc_get_freq(ledc_mode_t speed_mode, ledc_timer_t timer_num)
ESP_LOGW(LEDC_TAG, "LEDC timer not configured, call ledc_timer_config to set timer frequency");
return 0;
}
return (((uint64_t) src_clk_freq << LEDC_LL_FRACTIONAL_BITS) + (uint64_t) precision * clock_divider / 2) / precision / clock_divider;
return (((uint64_t) src_clk_freq << LEDC_LL_FRACTIONAL_BITS) + precision * clock_divider / 2) / (precision * clock_divider);
}
static inline uint32_t ilog2(uint32_t i)
{
assert(i > 0);
uint32_t log = 0;
while (i >>= 1) {
++log;
}
return log;
}
// https://www.espressif.com/sites/default/files/documentation/esp32_technical_reference_manual_en.pdf#ledpwm
uint32_t ledc_find_suitable_duty_resolution(uint32_t src_clk_freq, uint32_t timer_freq)
{
// Highest resolution is calculated when LEDC_CLK_DIV = 1 (i.e. div_param = 1 << LEDC_LL_FRACTIONAL_BITS)
uint32_t div = (src_clk_freq + timer_freq / 2) / timer_freq; // rounded
uint32_t duty_resolution = MIN(ilog2(div), SOC_LEDC_TIMER_BIT_WIDTH);
uint32_t div_param = ledc_calculate_divisor(src_clk_freq, timer_freq, 1 << duty_resolution);
if (LEDC_IS_DIV_INVALID(div_param)) {
div = src_clk_freq / timer_freq; // truncated
duty_resolution = MIN(ilog2(div), SOC_LEDC_TIMER_BIT_WIDTH);
div_param = ledc_calculate_divisor(src_clk_freq, timer_freq, 1 << duty_resolution);
if (LEDC_IS_DIV_INVALID(div_param)) {
duty_resolution = 0;
}
}
return duty_resolution;
}
static inline void IRAM_ATTR ledc_calc_fade_end_channel(uint32_t *fade_end_status, uint32_t *channel)