Implement hardware PWM support.

MarlinFirmware · Dec 26, 2024 · a46a9b2 · a46a9b2
1 parent 728ed0b
commit a46a9b2
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Showing 3 changed files with 68 additions and 9 deletions.
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.h b/Marlin/src/HAL/TEENSY40_41/HAL.h
@@ -61,6 +61,8 @@
 #undef PSTR
 #define PSTR(str) ({static const char *data = (str); &data[0];})
 
+#define HAL_CAN_SET_PWM_FREQ
+
 // ------------------------
 // Serial ports
 // ------------------------
@@ -221,11 +223,15 @@ class MarlinHAL {
 
   /**
    * Set the PWM duty cycle for the pin to the given value.
-   * No option to invert the duty cycle [default = false]
-   * No option to change the scale of the provided value to enable finer PWM duty control [default = 255]
+   * Optionally invert the duty cycle [default = false]
+   * Optionally change the scale of the provided value to enable finer PWM duty control [default = 255]
    */
-  static void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t=255, const bool=false) {
-    analogWrite(pin, v);
-  }
+  static void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size=255, const bool invert=false);
 
+  /**
+   * Set the PWM output frequency. This may affect multiple pins, though
+   * Teensy 4.x provides many timers affecting only a single pin.
+   * See: https://www.pjrc.com/teensy/td_pulse.html
+   */
+  static void set_pwm_frequency(const pin_t pin, const uint16_t f_desired);
 };
diff --git a/Marlin/src/HAL/TEENSY40_41/fast_pwm.cpp b/Marlin/src/HAL/TEENSY40_41/fast_pwm.cpp
@@ -0,0 +1,57 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2024 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifdef __IMXRT1062__
+
+#include "../../inc/MarlinConfig.h"
+
+#include "HAL.h"
+
+void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size /*=255*/, const bool invert) {
+
+  uint32_t bits = 1;
+  uint16_t value = v;
+
+  if (v > v_size) {
+    value = v_size;
+  }
+  value = invert ? v_size - value : value;
+
+  // Choose scale as smallest power of 2 which holds v_size.
+  uint32_t scale = 1;
+  while (scale < v_size) {
+    bits++;
+    scale *= 2;
+  }
+
+  uint32_t scaled_val = scale * value / v_size;
+
+  uint32_t prior = analogWriteResolution(bits);
+  analogWrite(pin, scaled_val);
+  analogWriteResolution(prior);
+}
+
+void MarlinHAL::set_pwm_frequency(const pin_t pin, const uint16_t f_desired) {
+  analogWriteFrequency(pin, f_desired);
+}
+
+#endif // __IMXRT1062__
diff --git a/Marlin/src/HAL/TEENSY40_41/inc/SanityCheck.h b/Marlin/src/HAL/TEENSY40_41/inc/SanityCheck.h
@@ -33,10 +33,6 @@
   #error "EMERGENCY_PARSER is not yet implemented for Teensy 4.0/4.1. Disable EMERGENCY_PARSER to continue."
 #endif
 
-#if ENABLED(FAST_PWM_FAN) || SPINDLE_LASER_FREQUENCY
-  #error "Features requiring Hardware PWM (FAST_PWM_FAN, SPINDLE_LASER_FREQUENCY) are not yet supported for Teensy 4.0/4.1."
-#endif
-
 #if HAS_TMC_SW_SERIAL
   #error "TMC220x Software Serial is not supported for Teensy 4.0/4.1."
 #endif