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I tried reactivating my RS485 sketches and already ran into problems. Following is my current setup. The connection follows this project.

Picture2
Picture21920×1440 210 KB

Mastercode:

#include <Arduino.h>

const int EnableTX = 3;

void setup() {
  Serial.begin(9600);
  pinMode(EnableTX,OUTPUT);
}

void loop() {  
  digitalWrite(EnableTX, HIGH);
  Serial.print("x");
  digitalWrite(EnableTX, LOW);  
  delay(1500);
}

Slavecode:

#include <Arduino.h>

const int EnableTX = 2;

void setup() {
  Serial.begin(9600);
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(EnableTX,OUTPUT);
}

void loop() {

  if(Serial.available()>0) {
    char x = Serial.read();
    digitalWrite(LED_BUILTIN, HIGH);
    delay(250);
    digitalWrite(LED_BUILTIN, LOW); 
    delay(250);  
  }
}

The idea is just to check communication between the two Nanos and listening in with the Sniffer. Sadly no messages are received. The Tx-Led on the Master blinks in the right frequency and on the oscilloscope I detect a signal between A-B (measuring channel 1 and subtracting channel 2)

01111000

this corresponds to the character 'x'. On the slave Rx-Led is not blinking and the built in LED also will also not blink. Therefore the serial.available() path is not reached. Listening in on COM14 (the RS485 sniffer) occasionally shows 'x'.

The sniffer and the Nanos are powered over the USB-Hub, but the monitors for the Nanos are closed.

My questions:

  1. Can I power the Nanos over USB since it is also used for the serial monitor?
  2. Can the Sniffer be used to send\read commands to either Master or Slave?