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RS485Receiver.ino

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+#include <Wire.h>
+#include <Adafruit_GFX.h>
+#include <Adafruit_SSD1306.h>
+
+// OLED setup
+#define SCREEN_WIDTH 128
+#define SCREEN_HEIGHT 64
+#define OLED_ADDRESS 0x3C
+Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
+
+// RS485 control pins
+#define DE_PIN 20
+#define RE_PIN 10
+
+void setup() {
+  // Initialize Serial1 for RS485 (TX=21, RX=9)
+  Serial.begin(115200);
+  Serial1.begin(1000000, SERIAL_8N1, 9, 21);
+
+  // Set DE and RE as outputs
+  pinMode(DE_PIN, OUTPUT);
+  pinMode(RE_PIN, OUTPUT);
+
+  // Enable receive mode
+  digitalWrite(DE_PIN, LOW);
+  digitalWrite(RE_PIN, LOW);
+
+  // Initialize OLED
+  Wire.begin(3, 4);  // SDA=3, SCL=4
+  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDRESS)) {
+    while (true)
+      ;  // Halt if display fails
+  }
+  display.clearDisplay();
+  display.setTextSize(1);
+  display.setTextColor(SSD1306_WHITE);
+  display.setCursor(0, 0);
+  display.println("Waiting for RS485...");
+  display.display();
+}
+
+void loop() {
+  if (Serial1.available()) {
+    uint8_t buffer[32];
+    int count = 0;
+
+    // Read all available bytes
+    while (Serial1.available() && count < sizeof(buffer)) {
+      buffer[count++] = Serial1.read();
+    }
+
+    // Display on Serial
+    Serial.print("recv: ");
+    for (int i = 0; i < count; i++) {
+      Serial.print("0x");
+      if (buffer[i] < 0x10) Serial.print("0");
+      Serial.print(buffer[i], HEX);
+      Serial.print(" ");
+    }
+    Serial.println();
+
+    // Display on OLED
+    display.clearDisplay();
+    display.setCursor(0, 0);
+    display.setTextSize(1);
+    display.println("Received:");
+    display.setCursor(0, 12);
+    display.setTextSize(1);
+
+    for (int i = 0; i < count; i++) {
+      display.print("0x");
+      if (buffer[i] < 0x10) display.print("0");
+      display.print(buffer[i], HEX);
+      display.print(" ");
+    }
+    display.display();
+  }
+}