Delete RAM data and delay function

inc/system_function.h

@@ -0,0 +1,12 @@
+#ifndef _SYSTEM_FUNCTION_
+#define _SYSTEM_FUNCTION_
+
+#include "stdint.h"
+
+#define RAM_ADDR_START 0x80
+#define RAM_ADDR_END   0xff
+
+void ram_erase(uint8_t ram_bank);
+void delay(uint16_t count);
+
+#endif