1 files changed, 1 insertions, 1 deletions
diff --git a/src/ao.h b/src/ao.h
index e2f137bd..aeceb870 100644
--- a/src/ao.h
+++ b/src/ao.h
@@ -981,7 +981,7 @@ struct ao_fifo {
  */
 
 #define AO_PACKET_MAX	8
-#define AO_PACKET_SYN		0xff
+#define AO_PACKET_SYN		(uint8_t) 0xff
 
 struct ao_packet {
 	uint8_t		addr;