diff --git a/libubb/swuart.c b/libubb/swuart.c
index 7839ffe..36a59ff 100644
--- a/libubb/swuart.c
+++ b/libubb/swuart.c
@@ -241,7 +241,7 @@ int swuart_open(uint32_t tx, uint32_t rx, int bps)
 
 	ubb_power(1);
 	OUT(tx);
-	CLR(tx);
+	SET(tx);
 	IN(rx);
 
 	return 0;