detect MCU flash size and config usart

Src/main.c

@@ -43,6 +43,8 @@ OF SUCH DAMAGE.
 #include "ldc1612.h"
 #include "tmp112.h"
 
+#define FLASH_SIZE_ADDR   (*(const uint16_t *)0x1FFFF7E0)
+
 /*!
     \brief      main function
     \param[in]  none
@@ -51,13 +53,41 @@ OF SUCH DAMAGE.
 */
 int main(void)
 {
+    systick_config();
+
+    /* Detect MCU type and configure USART accordingly */
+    mcu_detect_and_config();
+
+    uint16_t flash_kb = FLASH_SIZE_ADDR;
+
+    rs485_init();
+    printf("MCU Type detected: ");
+    switch (get_mcu_type()) {
+        case GD32E23XF4:
+            printf("GD32E23XF4 (using USART0)\r\n");
+            break;
+        case GD32E23XF6:
+            printf("GD32E23XF6 (using USART1)\r\n");
+            break;
+        case GD32E23XF8:
+            printf("GD32E23XF8 (using USART1)\r\n");
+            break;
+        default:
+            printf("Unknown (default to GD32E23XF8)\r\n");
+            break;
+    }
 
     setbuf(stdout, NULL);
-    systick_config();
+    
     rs485_init();
 
     led_init();
 
+    printf("Flash Size: %d KB\r\n", flash_kb);
+    printf("%x\r\n", flash_kb);
+
+    printf("Flash Size Bytes: %02X\r\n", flash_kb & 0xFF);
+
 #ifdef DEBUG_VERBOSE
     char hello_world[] = {"Hello World!\r\n"};