40 lines
1.6 KiB
C++
40 lines
1.6 KiB
C++
#include "Pwm.h"
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#include "Config.h"
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void PwmGenerator::begin() { pinMode(GPIO_PWM, OUTPUT); stop(); }
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bool PwmGenerator::start(uint32_t hz, uint8_t dutyPct, ActualPwm &a) {
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stop();
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uint8_t bits = LEDC_MAX_BITS;
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while (bits > 1 && static_cast<uint64_t>(hz) * (1ULL << bits) > 80000000ULL) --bits;
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if (!ledcAttachChannel(GPIO_PWM, hz, bits, LEDC_CHANNEL)) return false;
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const uint32_t top = (1UL << bits) - 1UL;
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const uint32_t duty = (static_cast<uint64_t>(top) * dutyPct + 50U) / 100U;
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if (!ledcWriteChannel(LEDC_CHANNEL, duty)) { ledcDetach(GPIO_PWM); return false; }
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const uint32_t actualHz = ledcReadFreq(GPIO_PWM);
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if (!actualHz) { ledcDetach(GPIO_PWM); return false; }
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a = {hz, actualHz, 100.0f * duty / top, bits};
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running_ = true;
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return true;
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}
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bool PwmGenerator::preview(uint32_t hz, uint8_t dutyPct, ActualPwm &a) {
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stop();
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uint8_t bits = LEDC_MAX_BITS;
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while (bits > 1 && static_cast<uint64_t>(hz) * (1ULL << bits) > 80000000ULL) --bits;
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if (!ledcAttachChannel(GPIO_PWM, hz, bits, LEDC_CHANNEL)) return false;
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ledcWriteChannel(LEDC_CHANNEL, 0); // query hardware without emitting test pulses
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const uint32_t actualHz = ledcReadFreq(GPIO_PWM);
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const uint32_t top = (1UL << bits) - 1UL;
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const uint32_t duty = (static_cast<uint64_t>(top) * dutyPct + 50U) / 100U;
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a = {hz, actualHz, 100.0f * duty / top, bits};
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ledcDetach(GPIO_PWM); pinMode(GPIO_PWM, OUTPUT); digitalWrite(GPIO_PWM, PWM_SAFE_LEVEL);
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return actualHz != 0;
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}
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void PwmGenerator::stop() {
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if (running_) ledcDetach(GPIO_PWM);
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pinMode(GPIO_PWM, OUTPUT); digitalWrite(GPIO_PWM, PWM_SAFE_LEVEL);
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running_ = false;
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}
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