🚸 Prevent M42 unintended pin change to output (#22493)

MarlinFirmware · Aug 9, 2021 · 0af762d · 0af762d
1 parent b567717
commit 0af762d
Showing 1 changed file with 32 additions and 4 deletions.
diff --git a/Marlin/src/gcode/control/M42.cpp b/Marlin/src/gcode/control/M42.cpp
@@ -31,6 +31,13 @@
  #include "../../module/temperature.h"
 #endif
 
+#ifdef MAPLE_STM32F1
+ // these are enums on the F1...
+ #define INPUT_PULLDOWN INPUT_PULLDOWN
+ #define INPUT_ANALOG INPUT_ANALOG
+ #define OUTPUT_OPEN_DRAIN OUTPUT_OPEN_DRAIN
+#endif
+
 void protected_pin_err() {
  SERIAL_ERROR_MSG(STR_ERR_PROTECTED_PIN);
 }
@@ -55,13 +62,20 @@ void GcodeSuite::M42() {
 
  if (!parser.boolval('I') && pin_is_protected(pin)) return protected_pin_err();
 
+ bool avoidWrite = false;
  if (parser.seenval('M')) {
  switch (parser.value_byte()) {
- case 0: pinMode(pin, INPUT); break;
+ case 0: pinMode(pin, INPUT); avoidWrite = true; break;
  case 1: pinMode(pin, OUTPUT); break;
- case 2: pinMode(pin, INPUT_PULLUP); break;
+ case 2: pinMode(pin, INPUT_PULLUP); avoidWrite = true; break;
  #ifdef INPUT_PULLDOWN
- case 3: pinMode(pin, INPUT_PULLDOWN); break;
+ case 3: pinMode(pin, INPUT_PULLDOWN); avoidWrite = true; break;
+ #endif
+ #ifdef INPUT_ANALOG
+ case 4: pinMode(pin, INPUT_ANALOG); avoidWrite = true; break;
+ #endif
+ #ifdef OUTPUT_OPEN_DRAIN
+ case 5: pinMode(pin, OUTPUT_OPEN_DRAIN); break;
  #endif
  default: SERIAL_ECHOLNPGM("Invalid Pin Mode"); return;
  }
@@ -99,8 +113,22 @@ void GcodeSuite::M42() {
  }
  #endif
 
- pinMode(pin, OUTPUT);
+ if (avoidWrite) {
+ SERIAL_ECHOLNPGM("?Cannot write to INPUT");
+ return;
+ }
+
+ // An OUTPUT_OPEN_DRAIN should not be changed to normal OUTPUT (STM32)
+ // Use M42 Px M1/5 S0/1 to set the output type and then set value
+ #ifndef OUTPUT_OPEN_DRAIN
+ pinMode(pin, OUTPUT);
+ #endif
  extDigitalWrite(pin, pin_status);
+
+ #ifdef ARDUINO_ARCH_STM32
+ // A simple I/O will be set to 0 by analogWrite()
+ if (pin_status <= 1) return;
+ #endif
  analogWrite(pin, pin_status);
 }