From 7a32e539fb3c13bfbe7c03c78a7d256d6de38592 Mon Sep 17 00:00:00 2001
From: bcostm <bco.stm@gmail.com>
Date: Wed, 8 Oct 2014 08:50:05 +0200
Subject: [PATCH] [NUCLEO_F091RC] pin_mode for Serial only if the pin is
 present

Same as all other targets.
---
 .../hal/TARGET_STM/TARGET_NUCLEO_F091RC/serial_api.c      | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F091RC/serial_api.c b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F091RC/serial_api.c
index 2d7aac7f7c..d15bfe0e51 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F091RC/serial_api.c
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F091RC/serial_api.c
@@ -168,8 +168,12 @@ void serial_init(serial_t *obj, PinName tx, PinName rx)
     // Configure the UART pins
     pinmap_pinout(tx, PinMap_UART_TX);
     pinmap_pinout(rx, PinMap_UART_RX);
-    pin_mode(tx, PullUp);
-    pin_mode(rx, PullUp);
+    if (tx != NC) {
+        pin_mode(tx, PullUp);
+    }
+    if (rx != NC) {
+        pin_mode(rx, PullUp);
+    }
 
     // Configure UART
     obj->baudrate = 9600;