detect MCU flash size to config diff usart

Src/main.c

@@ -51,12 +51,16 @@ OF SUCH DAMAGE.
 */
 int main(void)
 {
+    led_init();
+    mcu_detect_and_config();
 
     setbuf(stdout, NULL);
     systick_config();
     rs485_init();
 
-    led_init();
+    // led_init();
+
+    printf("Flash size: %d Kbytes\n", get_flash_size());
 
 #ifdef DEBUG_VERBOSE
     char hello_world[] = {"Hello World!\r\n"};