diff --git a/examples/uart/source/uart_429disco.adb b/examples/uart/source/uart_429disco.adb
index 5a2ee7c..bd200fa 100644
--- a/examples/uart/source/uart_429disco.adb
+++ b/examples/uart/source/uart_429disco.adb
@@ -1,7 +1,6 @@
 with STM32.F429Z;          use STM32.F429Z;
 use STM32.F429Z.Modules.GPIO;
 use STM32.F429Z.Modules.USART;
-use STM32.F429Z.Modules.RCC;
 
 with Ada.Real_Time;        use Ada.Real_Time;
 
@@ -23,8 +22,8 @@ procedure UART_429Disco is
 	end;
 
 	APB2_Frequency : constant := 90_000_000; -- Set by board support
-	Baud_Rate : constant := 115_200;
-	Ratio : constant := (APB2_Frequency + Baud_Rate / 2) / Baud_Rate;
+	Baud : constant := 115_200;
+	--Ratio : constant := (APB2_Frequency + Baud_Rate / 2) / Baud_Rate;
 
 	Period: constant Time_Span := Milliseconds(100);
 	Now: Time := Clock;
@@ -92,7 +91,8 @@ begin
 		UART_Module.CR3 := R;
 	end;
 
-	UART_Module.BRR := (DIV_Mantissa => Ratio / 16, DIV_Fraction => Ratio mod 16, others => 0);
+	--UART_Module.BRR := (DIV_Mantissa => Ratio / 16, DIV_Fraction => Ratio mod 16, others => 0);
+	UART_Module.BRR := Baud_Rate (Speed => Baud, OVER8 => False, Bus_Frequency => APB2_Frequency);
 
 	declare
 		R : Control_Register_1 := UART_Module.CR1;
@@ -109,4 +109,4 @@ begin
 		delay until Now;
 	end loop;
 
-end UART_429Disco;
\ No newline at end of file
+end UART_429Disco;
diff --git a/source/stm32-f4-usart.adb b/source/stm32-f4-usart.adb
new file mode 100644
index 0000000..10842a1
--- /dev/null
+++ b/source/stm32-f4-usart.adb
@@ -0,0 +1,17 @@
+package body STM32.F4.USART is
+
+	function Baud_Rate (
+		Speed: Positive;
+		OVER8: Boolean;
+		Bus_Frequency: Positive) 
+		return Baud_Rate_Register
+	is
+		Ratio : Natural := (Bus_Frequency + Speed / 2) / Speed;
+		Oversampling : Positive := (if OVER8 then 8 else 16);
+	begin
+		return (DIV_Mantissa => Ratio / Oversampling,
+			DIV_Fraction => Ratio mod Oversampling,
+			others => 0);
+	end;
+
+end STM32.F4.USART;
diff --git a/source/stm32-f4-usart.ads b/source/stm32-f4-usart.ads
index 651edc9..2543ee4 100644
--- a/source/stm32-f4-usart.ads
+++ b/source/stm32-f4-usart.ads
@@ -251,4 +251,10 @@ package STM32.F4.USART is
 		GTPR at 16#18# range 0 .. 31;
 	end record;
 
+	function Baud_Rate (
+		Speed: Positive;
+		OVER8: Boolean;
+		Bus_Frequency: Positive)
+		return Baud_Rate_Register;
+
 end STM32.F4.USART;