diff --git a/c64/kernal/iec_assert_data.s b/c64/kernal/iec_assert_data.s
new file mode 100644
index 00000000..98ef4891
--- /dev/null
+++ b/c64/kernal/iec_assert_data.s
@@ -0,0 +1,5 @@
+iec_assert_data:
+	lda $dd00
+	ora #$20
+	sta $dd00
+	rts