diff --git a/mendel.c b/mendel.c
index 36fba3b..8b11734 100644
--- a/mendel.c
+++ b/mendel.c
@@ -102,8 +102,10 @@ void io_init(void) {
 		WRITE(Z_ENABLE_PIN, 1); SET_OUTPUT(Z_ENABLE_PIN);
 	#endif
 	
-	WRITE(E_STEP_PIN, 0);	SET_OUTPUT(E_STEP_PIN);
-	WRITE(E_DIR_PIN,  0);	SET_OUTPUT(E_DIR_PIN);
+	#if defined E_STEP_PIN && defined E_DIR_PIN
+		WRITE(E_STEP_PIN, 0);	SET_OUTPUT(E_STEP_PIN);
+		WRITE(E_DIR_PIN,  0);	SET_OUTPUT(E_DIR_PIN);
+	#endif
 	#ifdef E_ENABLE_PIN
 		WRITE(E_ENABLE_PIN, 1); SET_OUTPUT(E_ENABLE_PIN);
 	#endif
diff --git a/pinio.h b/pinio.h
index c5ebaf6..3f0691e 100644
--- a/pinio.h
+++ b/pinio.h
@@ -131,12 +131,18 @@ Z Stepper
 Extruder
 */
 
-#define	_e_step(st)						WRITE(E_STEP_PIN, st)
-#define	e_step()							_e_step(1);
-#ifndef	E_INVERT_DIR
-	#define	e_direction(dir)			WRITE(E_DIR_PIN, dir)
+#if defined E_STEP_PIN && defined E_DIR_PIN
+	#define	_e_step(st)						WRITE(E_STEP_PIN, st)
+	#define	e_step()							_e_step(1);
+	#ifndef	E_INVERT_DIR
+		#define	e_direction(dir)		WRITE(E_DIR_PIN, dir)
+	#else
+		#define	e_direction(dir)		WRITE(E_DIR_PIN, dir^1)
+	#endif
 #else
-	#define	e_direction(dir)			WRITE(E_DIR_PIN, dir^1)
+	#define	_e_step(st)						do { } while (0)
+	#define	e_step()							do { } while (0)
+	#define	e_direction(dir)			do { } while (0)
 #endif
 
 /*