I need modify a demo software ATMEL_USB_MOUSE from olimex website. I found one small mistake in main.c : in function void write_str_USART0 an argument should be as const char. But I can not compile project, because error: error LNK2019: unresolved external symbol "struct _AT91S_HID * __cdecl AT91F_HID_Open(struct _AT91S_HID *,struct _AT91S_UDP *)" (?AT91F_HID_Open@@YAPAU_AT91S_HID@@PAU1@PAU_AT91S_UDP@@@Z) referenced in function "void __cdecl AT91F_USB_Open(void)" (?AT91F_USB_Open@@YAXXZ).
Dear collegues , could you explain me the problem?