RS485 Data Dropping

src/DcsBios.h

@@ -14,6 +14,7 @@
 #include "internal/ExportStreamListener.h"
 #include "internal/PollingInput.h"
 #include "internal/Protocol.h"
+#include "internal/Protocol.cpp.inc" // Needs to be a .cpp.inc to allow DCSBIOS_INCOMING_DATA_BUFFER_SIZE
 #include "internal/Addresses.h"
 
 

src/internal/DcsBiosNgRS485Slave.cpp.inc

@@ -107,7 +107,12 @@ namespace DcsBios {
 			case RX_WAIT_DATA:
 				rxtx_len--;
 				if (rx_datatype == RXDATA_DCSBIOS_EXPORT) {
-					parser.processCharISR(c);
+					if (rxtx_len <= parser.incomingDataBuffer.availableForWrite()) {
+						parser.processCharISR(c);
+					} else {
+						last_rx_time = micros();
+						state = SYNC;
+					}
 				}
 				if (rxtx_len == 0) {
 					state = RX_WAIT_CHECKSUM;
@@ -240,6 +245,14 @@ namespace DcsBios {
 	void loop() {
 		PollingInput::pollInputs();
 		ExportStreamListener::loopAll();
+
+		// Process incoming data outside of ISR
+		#ifdef DCSBIOS_DEFER_RS485_PROCESSING
+		if (!parser.incomingDataBuffer.isEmpty()) {
+			unsigned char nextByte = parser.incomingDataBuffer.get();
+			parser.processChar(nextByte);
+		}
+		#endif
 	}
 }
 #endif

src/internal/Protocol.cpp → src/internal/Protocol.cpp.inc

@@ -20,6 +20,9 @@ namespace DcsBios {
 	*/
 	void ProtocolParser::processCharISR(unsigned char c) {
 		incomingDataBuffer.put(c);
+
+		// For some reason RS485 slaves cannot process data here, while it works over USB. Perhaps due to the additonal overhead of the RS485 state machine? If DCSBIOS_RS485_SLAVE is defined, the processing is deferred to loop().
+		#ifndef DCSBIOS_DEFER_RS485_PROCESSING
 		if (processingData) return;
 
 		processingData = true;
@@ -31,10 +34,8 @@ namespace DcsBios {
 			unsigned char nextByte = incomingDataBuffer.get();
 			interrupts();
 			processChar(nextByte);
-#ifdef DCSBIOS_RS485_SLAVE
-			noInterrupts();
-#endif
 		}
+		#endif
 	}
 
 	void ProtocolParser::processChar(unsigned char c) {

src/internal/Protocol.h

@@ -9,6 +9,10 @@
 #define DCSBIOS_STATE_DATA_LOW 5
 #define DCSBIOS_STATE_DATA_HIGH 6
 
+#ifndef DCSBIOS_INCOMING_DATA_BUFFER_SIZE
+#define DCSBIOS_INCOMING_DATA_BUFFER_SIZE 64
+#endif
+
 #include "ExportStreamListener.h"
 #include "RingBuffer.h"
 
@@ -23,9 +27,10 @@ namespace DcsBios {
 			volatile unsigned char sync_byte_count;
 
 			ExportStreamListener* startESL;
-			RingBuffer<64> incomingDataBuffer;
 			volatile bool processingData;
 		public:
+			RingBuffer<DCSBIOS_INCOMING_DATA_BUFFER_SIZE> incomingDataBuffer;
+
 			void processChar(unsigned char c);
 			void processCharISR(unsigned char c);
 			ProtocolParser();

src/internal/RingBuffer.h

@@ -16,6 +16,7 @@ namespace DcsBios {
 		__attribute__((always_inline)) uint8_t get() { uint8_t ret = buffer[readpos]; readpos = ++readpos % SIZE; return ret; }
 		__attribute__((always_inline)) uint8_t getLength() { return (uint8_t)(writepos - readpos) % SIZE; }
 		__attribute__((always_inline)) void clear() { readpos = 0; writepos = 0; }
+		__attribute__((always_inline)) uint8_t availableForWrite() { return SIZE - getLength() - 1; }
 	};
 }