Fixed BESC spindle speed handling

Grbl_Esp32/data/spindles.yaml

@@ -99,7 +99,7 @@ PWM:
 BESC:
   min_pulse_us: 950
   max_pulse_us: 2050
-  speeds: 0=0% 30000=100%
+  # speeds: 0=0% 0=20% 2000=20% 5000=40% 10000=100%
   output_pin: gpio.4
   enable_pin: gpio.10
   tool: 40

Grbl_Esp32/src/Spindles/BESCSpindle.cpp

@@ -31,6 +31,7 @@
 
 */
 #include "BESCSpindle.h"
+#include "soc/ledc_struct.h"
 
 namespace Spindles {
     void BESC::init() {
@@ -53,30 +54,59 @@ namespace Spindles {
 
         _enable_pin.setAttr(Pin::Attr::Output);
 
+        // BESC PWM typically represents 0 speed as a 1ms pulse and max speed as a 2ms pulse
+
         // 1000000 is us/sec
-        const uint32_t besc_pulse_period_us = 1000000 / besc_pwm_freq;
+        const uint32_t pulse_period_us = 1000000 / besc_pwm_freq;
 
-        float _min_pulse_percent = 100.0 * _min_pulse_us / besc_pulse_period_us;
+        // Calculate the pulse length offset and scaler in counts of the LEDC controller
-        float _max_pulse_percent = 100.0 * _max_pulse_us / besc_pulse_period_us;
+        _min_pulse_counts  = _min_pulse_us << _pwm_precision / pulse_period_us;
+        _pulse_span_counts = (_max_pulse_us - _min_pulse_us) << _pwm_precision / pulse_period_us;
 
-        uint32_t max_speed = 20000;  // Default value if none given in speeds:
+        if (_speeds.size() == 0) {
-        if (_speeds.size() != 0) {
+            shelfSpeeds(4000, 20000);
-            log_info("Overriding PWM speed map for BESC");
-            // Extract the maximum speed from the provide speed map
-            max_speed = maxSpeed();
         }
 
-        // BESC PWM typically represents 0 speed as a 1ms pulse and max speed as a 2ms pulse
+        // We set the dev_speed scale in the speed map to the full PWM period (64K)
-        _speeds.clear();
+        // Then, in set_output, we map the dev_speed range of 0..64K to the pulse
-        _speeds.push_back({ 0, _min_pulse_percent });
+        // length range of ~1ms .. 2ms
-        _speeds.push_back({ max_speed, _max_pulse_percent });
-
         setupSpeeds(_pwm_period);
 
         stop();
         config_message();
     }
 
+    void IRAM_ATTR BESC::set_output(uint32_t duty) {
+        if (_output_pin.undefined()) {
+            return;
+        }
+
+        // to prevent excessive calls to ledcWrite, make sure duty has changed
+        if (duty == _current_pwm_duty) {
+            return;
+        }
+
+        _current_pwm_duty = duty;
+
+        //        if (_invert_pwm) {
+        //            duty = (1 << _pwm_precision) - duty;
+        //        }
+        // This maps the dev_speed range of 0..(1<<_pwm_precision) into the pulse length
+        // where _min_pulse_counts represents off and (_min_pulse_counts + _pulse_span_counts)
+        // represents full on.  Typically the off value is a 1ms pulse length and the
+        // full on value is a 2ms pulse.
+        uint32_t pulse_counts = _min_pulse_counts * _pulse_span_counts >> _pwm_precision;
+
+        //ledcWrite(_pwm_chan_num, duty);
+
+        // This was ledcWrite, but this is called from an ISR
+        // and ledcWrite uses RTOS features not compatible with ISRs
+        LEDC.channel_group[0].channel[0].duty.duty        = pulse_counts << 4;
+        bool on                                           = !!duty;
+        LEDC.channel_group[0].channel[0].conf0.sig_out_en = on;
+        LEDC.channel_group[0].channel[0].conf1.duty_start = on;
+    }
+
     // prints the startup message of the spindle config
     void BESC::config_message() {
         info_all("BESC spindle on Pin:%s Min:%dus Max:%dus Freq:%dHz Res:%dbits",

Grbl_Esp32/src/Spindles/BESCSpindle.h

@@ -37,9 +37,15 @@
 
 namespace Spindles {
     class BESC : public PWM {
-    protected:
+    private:
+        // Fixed
         const uint32_t besc_pwm_freq = 50;  // 50 Hz
 
+        // Calculated
+        uint16_t _pulse_span_counts;  // In counts of a 16-bit counter
+        uint16_t _min_pulse_counts;   // In counts of a 16-bit counter
+
+    protected:
         // Configurable
         uint32_t _min_pulse_us = 900;   // microseconds
         uint32_t _max_pulse_us = 2200;  // microseconds
@@ -55,6 +61,8 @@ namespace Spindles {
         void init() override;
         void config_message() override;
 
+        virtual void set_output(uint32_t duty) override;
+
         // Configuration handlers:
         void validate() const override { PWM::validate(); }