diff --git a/arch/arm/src/stm32/stm32_lowputc.c b/arch/arm/src/stm32/stm32_lowputc.c
index fe6f513867c..4d752796253 100644
--- a/arch/arm/src/stm32/stm32_lowputc.c
+++ b/arch/arm/src/stm32/stm32_lowputc.c
@@ -162,9 +162,9 @@
 
 #define STM32_USARTDIV32 (STM32_APBCLOCK / (STM32_CONSOLE_BAUD >> 1))
 
-/* The mantissa is then usartdiv32 * 32:
+/* The mantissa is then usartdiv32 / 32:
  *
- *   mantissa = 32 * usartdiv32
+ *   mantissa = usartdiv32 / 32/
  *
  * Eg. usartdiv32=1250, mantissa = 39 
  */
@@ -247,7 +247,7 @@ void stm32_lowsetup(void)
   uint32_t cr;
 #endif
 
-  /* Enable the selected USARTs and configure GPIO pins need byed the
+  /* Enable the selected USARTs and configure GPIO pins need by the
    * the selected USARTs.  NOTE: The serial driver later depends on
    * this pin configuration -- whether or not a serial console is selected.
    *
diff --git a/arch/arm/src/stm32/stm32_serial.c b/arch/arm/src/stm32/stm32_serial.c
index a529285f451..7255ef491fa 100644
--- a/arch/arm/src/stm32/stm32_serial.c
+++ b/arch/arm/src/stm32/stm32_serial.c
@@ -425,8 +425,8 @@ static inline void up_disableusartint(struct up_dev_s *priv, uint16_t *ie)
 static int up_setup(struct uart_dev_s *dev)
 {
   struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
-#ifdef CONFIG_SUPPRESS_UART_CONFIG
-  uint32_t uartdiv32;
+#ifndef CONFIG_SUPPRESS_UART_CONFIG
+  uint32_t usartdiv32;
   uint32_t mantissa;
   uint32_t fraction;
   uint32_t brr;
@@ -483,7 +483,7 @@ static int up_setup(struct uart_dev_s *dev)
 
   /* Configure hardware flow control -- Not yet supported */
 
-  up_serialout(priv, STM32_USART_CR1_OFFSET, regval);
+  up_serialout(priv, STM32_USART_CR3_OFFSET, regval);
 
   /* Configure the USART Baud Rate.  The baud rate for the receiver and
    * transmitter (Rx and Tx) are both set to the same value as programmed
@@ -521,7 +521,7 @@ static int up_setup(struct uart_dev_s *dev)
   up_serialout(priv, STM32_USART_CR1_OFFSET, regval);
 #endif
 
-  /* Set up the cache interrupt enables value */
+  /* Set up the cached interrupt enables value */
 
   priv->ie    = 0;
   return OK;