Dateien geordnet

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

Software/ManualSend/ManualSend.ino

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+/*// This sketch allows manual setting of the RS485-connected pins via serial terminal commands
+
+Commands are:
+r+ – enable read mode (^RE ← LOW)
+r- – disable read mode (^RE ← HIGH)
+w+ – enable write mode (DE ← HIGH)
+w- – disable write mode (DE ← LOW)
+h  – send HIGH level on DI
+l  – send LOW level on DI
+
+//*/
+
+#if defined(ARDUINO_AVR_UNO)
+  #define RS485_RO 5
+  #define RS485_RE 4
+  #define RS485_DE 3
+  #define RS485_DI 2
+  #define BOARD "Arduino Uno"
+#endif
+#if defined(ARDUINO_AVR_NANO)
+  #define RS485_RO 3
+  #define RS485_RE 2
+  #define RS485_DE 4
+  #define RS485_DI 5
+  #define BOARD "Arduino Nano"
+#endif
+
+String command = "";
+bool doPrint = false;
+// the setup function runs once when you press reset or power the board
+void setup() {
+  // initialize digital pin LED_BUILTIN as an output.
+  pinMode(RS485_RO, INPUT);
+  pinMode(RS485_RE, OUTPUT);
+  pinMode(RS485_DE, OUTPUT);
+  pinMode(RS485_DI, OUTPUT);
+  digitalWrite(RS485_RE,LOW);
+  digitalWrite(RS485_DE,LOW);
+  digitalWrite(RS485_DI,LOW);
+  Serial.begin(115200);
+  Serial.println(F("this is Projekte/Arduino/MAX485/ManualSend"));
+  Serial.println(F("send any of the followning commands:"));
+  Serial.println(F("- r+ (enable read)\n- r- (disable read)\n- w+ (enable write)\n- w- (disable write)\n- h (for high)\n- l (for low)"));
+}
+
+// the loop function runs over and over again forever
+void loop() {
+  while (Serial.available()){
+    char inChar = (char)Serial.read();
+    if (inChar == '\n') {
+      process(command);
+      command = ""; 
+      doPrint = true;
+    } else {
+      command += inChar;
+    }
+  }
+  if (doPrint){
+    printState();
+    delay(1000);
+  }
+}
+
+void printState(){
+  Serial.print("RE = ");
+  Serial.print(1-digitalRead(RS485_RE));
+  Serial.print(", DE = ");
+  Serial.print(digitalRead(RS485_DE));
+  Serial.print(", DI = ");
+  Serial.print(digitalRead(RS485_DI));
+  Serial.print(", RO = ");
+  Serial.println(digitalRead(RS485_RO));
+}
+
+void process(String command){
+  Serial.print(F("received:"));
+  Serial.println(command);
+  if (command == "r+") digitalWrite(RS485_RE,LOW);
+  if (command == "r-") digitalWrite(RS485_RE,HIGH);
+  if (command == "w+") digitalWrite(RS485_DE,HIGH);
+  if (command == "w-") digitalWrite(RS485_DE,LOW);
+  if (command == "h") digitalWrite(RS485_DI,HIGH);
+  if (command == "l") digitalWrite(RS485_DI,LOW);
+  printState();
+}

Software/ManualSend/Readme.md

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+Erkenntnisse:
+
+1. Wenn alle Treiber inaktiv sind, also bei allen Teilnehmer DI = Low ist, kommt vom RO ein High-Signal
+2. das High-Signal ist dominant, d.h. wenn mehrere Teilnehmer senden, und mindestens ein Teilnehmer eine 1 auf den Bus legt, erhalten alle am RO einen HIGH-Pegel