diff --git a/hardware.h b/hardware.h
index 0a79e24..0e2c9f3 100644
--- a/hardware.h
+++ b/hardware.h
@@ -15,7 +15,7 @@ void hardware_init(class CPU &);
 void hardware_checkpoint(class Stream &);
 void hardware_restore(class Stream &);
 
-#ifdef __PS2DRV_H__
+#if defined(__PS2DRV_H__) && defined(USE_KBD)
 extern class PS2Driver ps2;
 #endif
 #if defined(__SPIRAM_H__) && defined(USE_SPIRAM)