diff --git a/can/can_common.h b/can/can_common.h
new file mode 100644
index 0000000..87e2922
--- /dev/null
+++ b/can/can_common.h
@@ -0,0 +1,3 @@
+// We have a bit of a mess with too many useful usages of CAN and too little documentation at https://github.com/rusefi/rusefi/wiki/CAN
+
+#define GDI4_BASE_ADDRESS 0xF0
\ No newline at end of file