Merge pull request #12186 from mprse/fix_for_issue_12172_stm_serial

STM serial init: Set pin function only if pin is defined (not NC)
ARMmbed · Jan 7, 2020 · 5d71e69 · 5d71e69
2 parents 7d8eec4 + 79d16ae
commit 5d71e69
Showing 1 changed file with 2 additions and 3 deletions.
diff --git a/targets/TARGET_STM/serial_api.c b/targets/TARGET_STM/serial_api.c
@@ -157,13 +157,12 @@ static void _serial_init_direct(serial_t *obj, const serial_pinmap_t *pinmap)
     MBED_ASSERT(obj_s->index >= 0);
 
     // Configure UART pins
-    pin_function(pinmap->tx_pin, pinmap->tx_function);
-    pin_function(pinmap->rx_pin, pinmap->rx_function);
-
     if (pinmap->tx_pin != NC) {
+        pin_function(pinmap->tx_pin, pinmap->tx_function);
         pin_mode(pinmap->tx_pin, PullUp);
     }
     if (pinmap->rx_pin != NC) {
+        pin_function(pinmap->rx_pin, pinmap->rx_function);
         pin_mode(pinmap->rx_pin, PullUp);
     }