From b0896bbb427467b39f41606259b20a914d084dbb Mon Sep 17 00:00:00 2001
From: Paolo Calao <paolo.calao@gmail.com>
Date: Wed, 30 Sep 2020 13:08:40 +0200
Subject: [PATCH] analogWrite with negative value to delete pwm objects

---
 cores/arduino/wiring_analog.cpp | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/cores/arduino/wiring_analog.cpp b/cores/arduino/wiring_analog.cpp
index ab4cd928..328ed8fd 100644
--- a/cores/arduino/wiring_analog.cpp
+++ b/cores/arduino/wiring_analog.cpp
@@ -45,14 +45,22 @@ void analogWrite(pin_size_t pin, int val)
   if (pin >= PINS_COUNT) {
     return;
   }
-  float percent = (float)val/(float)((1 << write_resolution)-1);
   mbed::PwmOut* pwm = digitalPinToPwm(pin);
-  if (pwm == NULL) {
+  if ((pwm == NULL) && (val > 0)) {
     pwm = new mbed::PwmOut(digitalPinToPinName(pin));
     digitalPinToPwm(pin) = pwm;
     pwm->period_ms(2); //500Hz
+    float percent = (float)val/(float)((1 << write_resolution)-1);
+    pwm->write(percent);
+  } 
+  else if ((pwm != NULL) && (val < 0)) {
+    delete pwm;
+    digitalPinToPwm(pin) = NULL;
+  } 
+  else if ((pwm != NULL) && (val > 0)) {
+    float percent = (float)val/(float)((1 << write_resolution)-1);
+    pwm->write(percent);
   }
-  pwm->write(percent);
 }
 
 void analogWriteResolution(int bits)