Add MY_RS485_DE_INVERSE define to invert the device enable pin polarity (#1358)

* Add MY_RS485_DE_INVERSE define to invert the device enable pin polarity

Author: ltigges

MyConfig.h

@@ -249,6 +249,12 @@
  */
 //#define MY_RS485_DE_PIN (2)
 
+/**
+ * @def MY_RS485_DE_INVERSE
+ * @brief Define this if RS485 driver enable pin polarity is inverted (low-active).
+ */
+//#define MY_RS485_DE_INVERSE
+
 /**
  * @def MY_RS485_HWSERIAL
  * @brief Define this if RS485 is connected to a hardware serial port.
@@ -2317,6 +2323,8 @@
 #define MY_OTA_USE_I2C_EEPROM
 // RS485
 #define MY_RS485
+#define MY_RS485_DE_PIN
+#define MY_RS485_DE_INVERSE
 #define MY_RS485_HWSERIAL
 // RF24
 #define MY_RADIO_RF24

hal/transport/RS485/MyTransportRS485.cpp

@@ -57,9 +57,13 @@
 #endif
 
 #if defined(MY_RS485_DE_PIN)
+#if !defined(MY_RS485_DE_INVERSE)
 #define assertDE() hwDigitalWrite(MY_RS485_DE_PIN, HIGH); delayMicroseconds(5)
 #define deassertDE() hwDigitalWrite(MY_RS485_DE_PIN, LOW)
-
+#else
+#define assertDE() hwDigitalWrite(MY_RS485_DE_PIN, LOW); delayMicroseconds(5)
+#define deassertDE() hwDigitalWrite(MY_RS485_DE_PIN, HIG)
+#endif
 #else
 #define assertDE()
 #define deassertDE()
@@ -264,7 +268,11 @@ bool transportSend(const uint8_t to, const void* data, const uint8_t len, const
 	}
 
 #if defined(MY_RS485_DE_PIN)
+#if !defined(MY_RS485_DE_INVERSE)
 	hwDigitalWrite(MY_RS485_DE_PIN, HIGH);
+#else
+	hwDigitalWrite(MY_RS485_DE_PIN, LOW);
+#endif
 	delayMicroseconds(5);
 #endif
 
@@ -310,7 +318,11 @@ bool transportSend(const uint8_t to, const void* data, const uint8_t len, const
 	_dev.flush();
 #endif
 #endif
+#if !defined(MY_RS485_DE_INVERSE)
 	hwDigitalWrite(MY_RS485_DE_PIN, LOW);
+#else
+	hwDigitalWrite(MY_RS485_DE_PIN, HIGH);
+#endif
 #endif
 	return true;
 }
@@ -324,7 +336,11 @@ bool transportInit(void)
 	_serialReset();
 #if defined(MY_RS485_DE_PIN)
 	hwPinMode(MY_RS485_DE_PIN, OUTPUT);
+#if !defined(MY_RS485_DE_INVERSE)
 	hwDigitalWrite(MY_RS485_DE_PIN, LOW);
+#else
+	hwDigitalWrite(MY_RS485_DE_PIN, HIGH);
+#endif
 #endif
 	return true;
 }

keywords.txt

@@ -233,6 +233,7 @@ MY_RFM69_TX_POWER_DBM	LITERAL1
 MY_RS485	LITERAL1
 MY_RS485_BAUD_RATE	LITERAL1
 MY_RS485_DE_PIN	LITERAL1
+MY_RS485_DE_INVERSE	LITERAL1
 MY_RS485_HWSERIAL	LITERAL1
 MY_RS485_MAX_MESSAGE_LENGTH	LITERAL1
 MY_RS485_SOH_COUNT	LITERAL1