OLED + rotary encoder

purrChestrion-arduino/purrChestrion-arduino.ino

@@ -1,6 +1,6 @@
 #define FW_VER 1.0
-#define USE_OLED true // LEDC68 (Gotek alphanumeric displays)
-#define USE_ENCODER false
+#define USE_OLED true // OLED displays
+#define USE_ENCODER true
 
 // include libraries
 #include <Adafruit_MCP23X17.h>
@@ -18,7 +18,9 @@
 #endif
 
 #if USE_ENCODER
-
+  #define ENCODER_CLK 2
+  #define ENCODER_DT 3
+  int lastClk = HIGH;
 #endif
 
 // Instantiate libraries
@@ -93,10 +95,9 @@ MCPOutput noteToMCP[32] = {
 void updateOLED() {
 #if USE_OLED
     oled.clearDisplay();
-    oled.drawBitmap(0, 0, midich, MIDICH_WIDTH, MIDICH_HEIGHT, 1);
-    oled.setCursor(88, 18);
+    oled.drawBitmap(0, 13, midich, MIDICH_WIDTH, MIDICH_HEIGHT, 1);
+    oled.setCursor(86, 32);
     oled.setTextColor(SSD1306_WHITE);
-    oled.setTextSize(1);
   if (currentMidiChannel == MIDI_CHANNEL_OMNI) {
     oled.print("ALL");
   } else {
@@ -106,6 +107,26 @@ void updateOLED() {
 #endif
 }
 
+void checkEncoder() {
+  #if USE_ENCODER
+    int newClk = digitalRead(ENCODER_CLK);
+    if (newClk != lastClk && newClk == LOW) {
+      if (digitalRead(ENCODER_DT) == LOW) {
+        currentMidiChannel++;
+      } else {
+        currentMidiChannel--;
+      }
+
+      // Wraparound: OMNI = 0, channels 1–16
+      if (currentMidiChannel > 16) currentMidiChannel = 0;
+      if (currentMidiChannel < 0) currentMidiChannel = 16;
+
+      updateOLED();
+    }
+    lastClk = newClk;
+  #endif
+}
+
 void setup() {
   #if USE_OLED
     if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // I2C addr 0x3C
@@ -122,6 +143,10 @@ void setup() {
     }
   #endif
 
+  #if USE_ENCODER
+    pinMode(ENCODER_CLK, INPUT_PULLUP);
+    pinMode(ENCODER_DT, INPUT_PULLUP);
+  #endif
   // Midi Activity LED on Pin 13 (aka LED_BUILTIN)
   pinMode(LED_BUILTIN, OUTPUT);
 
@@ -146,6 +171,10 @@ void setup() {
 void loop() {
   MIDI.read();
 
+  #if USE_ENCODER
+    checkEncoder();
+  #endif
+
   // LED feedback
   if (ledActive && millis() - ledOnTime >= ledDuration) {
     digitalWrite(LED_BUILTIN, LOW);