diff --git a/configs/samd21-xplained/include/board.h b/configs/samd21-xplained/include/board.h
index f60461a9560..7e804abddd7 100644
--- a/configs/samd21-xplained/include/board.h
+++ b/configs/samd21-xplained/include/board.h
@@ -412,7 +412,7 @@
 
 #define BOARD_SERCOM3_GCLKGEN        0
 #define BOARD_SERCOM3_SLOW_GCLKGEN   BOARD_SERCOM05_SLOW_GCLKGEN
-#define BOARD_SERCOM3_MUXCONFIG      (USART_CTRLA_RXPAD1 | USART_CTRLA_TXPAD0)
+#define BOARD_SERCOM3_MUXCONFIG      (USART_CTRLA_RXPAD1 | USART_CTRLA_TXPAD0_1)
 #define BOARD_SERCOM3_PINMAP_PAD0    PORT_SERCOM3_PAD0_1 /* USART TX */
 #define BOARD_SERCOM3_PINMAP_PAD1    PORT_SERCOM3_PAD1_1 /* USART RX */
 #define BOARD_SERCOM3_PINMAP_PAD2    0