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Code Issues Releases Wiki Activity

Started re-writing pwm channel assignment based on Brian's comments

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This commit is contained in:
Stefan de Bruijn
2020-11-03 17:12:08 +01:00
parent a30f289598
commit 8bfce04eda
1 changed files with 61 additions and 7 deletions
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68
Grbl_Esp32/src/PinUsers/PwmPin.cpp
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@@ -8,11 +8,12 @@
namespace PinUsers {
class NativePwm : public PwmDetail {
static LimitedResource<8>& PwmChannelResources() {
// The ESP32 chip has 16 PWM channels, but the second 8 channels share the same timers as the first 8.
// So, in essense, we use only 8 here, so we can configure them independently.
static NativePwm** PwmChannelResources() {
// The ESP32 chip has 16 PWM channels, but there are 4 timers, 2 hardware instances per timer and 2
// software instances per timer.
static LimitedResource<8> instances_;
static NativePwm* instances_[16] = { nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr };
return instances_;
}
@@ -40,11 +41,50 @@ namespace PinUsers {
return precision - 1;
}
static int TryGrabChannel(uint32_t frequency) {
auto instances = PwmChannelResources();
// 1. Attempt to re-use the same frequency
for (int i = 0; i < 4; ++i) {
if (instances[i * 2] != nullptr && instances[i * 2 + 1] == nullptr) {
// See if this is a frequency match:
if (instances[i * 2]->frequency_ == frequency) {
return i * 2 + 1;
}
}
}
// 2. No luck. Check if we have free slots in the hardware PWM channels / timers
for (int i = 0; i < 4; ++i) {
if (instances[i * 2] == nullptr) {
return i * 2;
}
}
// 3. Check if we have free slots in the software PWM channels with the same frequency
for (int i = 0; i < 4; ++i) {
if (instances[i * 2]->frequency_ == frequency) {
if (instances[i * 2 + 8] == nullptr) {
return i * 2 + 8;
} else if (instances[i * 2 + 9] == nullptr) {
// See if this is a frequency match:
return i * 2 + 9;
}
}
}
// 4. Re-assign hardware PWM channels to software channels.
// TODO: Implement
// 5. Nothing is available.
return -1;
}
public:
NativePwm(Pin pin, uint32_t frequency, uint32_t maxDuty) : frequency_(frequency), maxDuty_(maxDuty) {
NativePwm(Pin pin, uint32_t frequency, uint32_t maxDuty) : frequency_(frequency), maxDuty_(maxDuty), pin_(pin) {
auto native = pin.getNative(Pin::Capabilities::PWM | Pin::Capabilities::Native);
pwmChannel_ = PwmChannelResources().tryClaim();
pwmChannel_ = TryGrabChannel(frequency);
Assert(pwmChannel_ != -1, "PWM Channel could not be claimed. Are all PWM channels in use?");
resolutionBits_ = calculatePwmPrecision(frequency);
@@ -54,6 +94,10 @@ namespace PinUsers {
ledcWrite(pwmChannel_, 0);
// grbl_msg_sendf(CLIENT_SERIAL, MsgLevel::Info, "PWM Output:%d on Pin:%s Freq:%0.0fHz", _number, _pin.name().c_str(), _pwm_frequency);
// Store instance:
auto instances = PwmChannelResources();
instances[pwmChannel_] = this;
}
uint32_t getFrequency() const override { return frequency_; }
@@ -71,8 +115,18 @@ namespace PinUsers {
}
~NativePwm() override {
auto native = pin_.getNative(Pin::Capabilities::PWM | Pin::Capabilities::Native);
ledcWrite(pwmChannel_, 0);
PwmChannelResources().release(pwmChannel_);
ledcDetachPin(native);
// Release resource:
auto instances = PwmChannelResources();
for (int i = 0; i < 16; ++i) {
if (instances[i] == this) {
instances[i] = nullptr;
}
}
}
};