add i2c check for display

Signed-off-by: Peter Siegmund <developer@mars3142.org>

firmware/main/i2c_checker.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include "esp_err.h"
+
+#define DISPLAY_I2C_ADDRESS 0x3C
+
+#if defined(CONFIG_IDF_TARGET_ESP32S3)
+#define I2C_MASTER_SDA_PIN GPIO_NUM_35
+#define I2C_MASTER_SCL_PIN GPIO_NUM_36
+#else
+/// just dummy pins, because of compile check
+#define I2C_MASTER_SDA_PIN GPIO_NUM_20
+#define I2C_MASTER_SCL_PIN GPIO_NUM_21
+#endif
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+    esp_err_t i2c_bus_scan_and_check(void);
+#ifdef __cplusplus
+}
+#endif