From 4ac10f53d72eae76fdb4f447620bb196a1b3618a Mon Sep 17 00:00:00 2001
From: Frank Benkert <frank.benkert@avat.de>
Date: Tue, 20 Oct 2015 05:58:34 +0800
Subject: [PATCH] Reconfigure System I/O when using USART1

---
 arch/arm/src/samv7/sam_lowputc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm/src/samv7/sam_lowputc.c b/arch/arm/src/samv7/sam_lowputc.c
index 1897cd17f85..d09d8fcd8af 100644
--- a/arch/arm/src/samv7/sam_lowputc.c
+++ b/arch/arm/src/samv7/sam_lowputc.c
@@ -54,6 +54,7 @@
 
 #include "chip/sam_uart.h"
 #include "chip/sam_pinmap.h"
+#include "chip/sam_matrix.h"
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -353,6 +354,13 @@ void sam_lowsetup(void)
 #ifdef CONFIG_USART1_IFLOWCONTROL
   (void)sam_configgpio(GPIO_USART1_RTS);
 #endif
+  /* To use the USART1 as an USART, the SYSIO Pin4 must be bound to PB4
+   * instead of TDI
+   */
+
+  uint32_t sysioreg = getreg32(SAM_MATRIX_CCFG_SYSIO);
+  sysioreg |= MATRIX_CCFG_SYSIO_SYSIO4;
+  putreg32(sysioreg, SAM_MATRIX_CCFG_SYSIO);
 #endif
 
 #ifdef CONFIG_SAMV7_USART2