Set TX bit in defined, recessive state (for in case it is wired)

Author: 0xCAFEDECAF

examples/LiveWebPage/LiveWebPage.ino

@@ -92,9 +92,11 @@
 #ifdef ARDUINO_ARCH_ESP32
  #ifdef CONFIG_IDF_TARGET_ESP32S2
   #define RX_PIN GPIO_NUM_33
+  #define TX_PIN GPIO_NUM_18
  #else
   // Note: GPIO_NUM_22 is also LED pin on Lilygo TTGO T7 V1.3 Mini32
   #define RX_PIN GPIO_NUM_22
+  #define TX_PIN GPIO_NUM_21
  #endif
 #else // ! ARDUINO_ARCH_ESP32
   #if defined ARDUINO_ESP8266_GENERIC || defined ARDUINO_ESP8266_ESP01
@@ -106,6 +108,7 @@
   //#define RX_PIN D3  // GPIO0 - pulled up - Boot fails
   //#define RX_PIN D4  // GPIO2 - pulled up
   //#define RX_PIN D8  // GPIO15 - pulled to GND - Boot fails
+  #define TX_PIN D3
 #endif // ARDUINO_ARCH_ESP32
 
 // TODO - reduce size of large JSON packets like the ones containing guidance instruction icons
@@ -1082,6 +1085,7 @@ void setup()
   #define STR(x) #x
     Serial.printf_P(PSTR("Setting up VAN bus receiver on pin %s (GPIO%u)\n"), XSTR(RX_PIN), RX_PIN);
     VanBusRx.Setup(RX_PIN, VAN_PACKET_QUEUE_SIZE);
+    VanBusRx.SetTxPinRecessive(TX_PIN);
     Serial.printf_P(PSTR("VanBusRx queue of size %d is set up\n"), VanBusRx.QueueSize());
 
     IrSetup();

examples/PacketParser/PacketParser.ino

@@ -59,10 +59,11 @@
 #ifdef ARDUINO_ARCH_ESP32
  #ifdef CONFIG_IDF_TARGET_ESP32S2
   #define RX_PIN GPIO_NUM_33
+  #define TX_PIN GPIO_NUM_18
  #else
   // Note: GPIO_NUM_22 is also LED pin on Lilygo TTGO T7 V1.3 Mini32
   #define RX_PIN GPIO_NUM_22
-
+  #define TX_PIN GPIO_NUM_21
  #endif
 #else // ! ARDUINO_ARCH_ESP32
   #if defined ARDUINO_ESP8266_GENERIC || defined ARDUINO_ESP8266_ESP01
@@ -71,6 +72,7 @@
   #endif // defined ARDUINO_ESP8266_GENERIC || defined ARDUINO_ESP8266_ESP01
   // For WEMOS D1 mini board we use D2 (GPIO 4)
   #define RX_PIN D2
+  #define TX_PIN D3
 #endif // ARDUINO_ARCH_ESP32
 
 // Packet parsing
@@ -3994,6 +3996,7 @@ void setup()
     // set up the receive queue a bit larger than the default of 15
   #define VAN_PACKET_QUEUE_SIZE 60
     VanBusRx.Setup(RX_PIN, VAN_PACKET_QUEUE_SIZE);
+    VanBusRx.SetTxPinRecessive(TX_PIN);
     Serial.printf_P(PSTR("VanBusRx queue of size %d is set up\n"), VanBusRx.QueueSize());
 } // setup
 

examples/VanBusDump/VanBusDump.ino

@@ -74,9 +74,11 @@
 #ifdef ARDUINO_ARCH_ESP32
  #ifdef CONFIG_IDF_TARGET_ESP32S2
   #define RX_PIN GPIO_NUM_33
+  #define TX_PIN GPIO_NUM_18
  #else
   // Note: GPIO_NUM_22 is also LED pin on Lilygo TTGO T7 V1.3 Mini32
   #define RX_PIN GPIO_NUM_22
+  #define TX_PIN GPIO_NUM_21
  #endif
 #else // ! ARDUINO_ARCH_ESP32
   #if defined ARDUINO_ESP8266_GENERIC || defined ARDUINO_ESP8266_ESP01
@@ -85,6 +87,7 @@
   #endif // defined ARDUINO_ESP8266_GENERIC || defined ARDUINO_ESP8266_ESP01
   // For WEMOS D1 mini board we use D2 (GPIO 4)
   #define RX_PIN D2
+  #define TX_PIN D3
 #endif // ARDUINO_ARCH_ESP32
 
 void setup()
@@ -128,6 +131,7 @@ void setup()
   #define STR(x) #x
     Serial.printf_P(PSTR("Setting up VAN bus receiver on pin %s (GPIO%u)\n"), XSTR(RX_PIN), RX_PIN);
     VanBusRx.Setup(RX_PIN);
+    VanBusRx.SetTxPinRecessive(TX_PIN);
     Serial.printf_P(PSTR("VanBusRx queue of size %d is set up\n"), VanBusRx.QueueSize());
 } // setup
 

src/VanBusRx.cpp

@@ -1320,6 +1320,13 @@ bool TVanPacketRxQueue::Setup(uint8_t rxPin, int queueSize)
     return true;
 } // TVanPacketRxQueue::Setup
 
+// If the TX pin is connected: make sure it does not affect the bus
+void TVanPacketRxQueue::SetTxPinRecessive(uint8_t txPin)
+{
+    pinMode(txPin, OUTPUT);
+    digitalWrite(txPin, VAN_BIT_RECESSIVE);  // Set bus state to 'recessive' (CANH and CANL: not driven)
+} // TVanPacketRxQueue::SetTxPinRecessive
+
 // Copy a VAN packet out of the receive queue, if available. Otherwise, returns false.
 // If a valid pointer is passed to 'isQueueOverrun', will report then clear any queue overrun condition.
 bool TVanPacketRxQueue::Receive(TVanPacketRxDesc& pkt, bool* isQueueOverrun)

src/VanBusRx.h

@@ -381,6 +381,7 @@ class TVanPacketRxQueue
     { }
 
     bool Setup(uint8_t rxPin, int queueSize = VAN_DEFAULT_RX_QUEUE_SIZE);
+    void SetTxPinRecessive(uint8_t txPin);
     bool Available() const { ISR_SAFE_GET(bool, tail->state == VAN_RX_DONE); }
     bool Receive(TVanPacketRxDesc& pkt, bool* isQueueOverrun = NULL);