implement new auto detect display for sh1106 and ssd1306

src/helpers/ui/AutoDetectDisplay.cpp

@@ -0,0 +1,45 @@
+#include "AutoDetectDisplay.h"
+#include <MeshCore.h>
+
+int AutoDetectDisplay::getDisplayStatus(TwoWire& wire, uint8_t addr) {
+  int status = -1;
+  for(int i = 0; i < 4; i++){
+
+    // request display status
+    wire.beginTransmission(addr);
+    wire.write((uint8_t)0x00);
+
+    // ensure response received
+    if (wire.endTransmission() != 0) return -1; // expect success
+    if (wire.requestFrom((int)addr, 1) == 0) return -1; // expect at least 1 byte
+
+    // ensure two consecutive reads are the same
+    int previous = status;
+    status = wire.read() & 0x0F;
+    if(status == previous){
+      break;
+    }
+
+  }
+  return status;
+}
+
+bool AutoDetectDisplay::begin() {
+
+  // request status from display address
+  int status = getDisplayStatus(Wire, DISPLAY_ADDRESS);
+  MESH_DEBUG_PRINTLN("AutoDetectDisplay: status=0x%02X", status);
+
+  // detect SH1106
+  if(status == 0x00 || status == 0x08){
+    MESH_DEBUG_PRINTLN("AutoDetectDisplay: SH1106 detected");
+    _impl = &_sh1106;
+    return _sh1106.begin();
+  }
+
+  // fallback to SSD1306
+  MESH_DEBUG_PRINTLN("AutoDetectDisplay: falling back to SSD1306");
+  _impl = &_ssd1306;
+  return _ssd1306.begin();
+
+}