diff --git a/HAL/STM32/stm32f4xx_it.c b/HAL/STM32/stm32f4xx_it.c
index 54212d0..59b4fdd 100644
--- a/HAL/STM32/stm32f4xx_it.c
+++ b/HAL/STM32/stm32f4xx_it.c
@@ -54,38 +54,6 @@ extern void Limit_PinChangeISR(void);
 extern void System_PinChangeISR(void);
 
 
-void SysTick_Init(void)
-{
-	RCC_ClocksTypeDef RCC_Clocks;
-
-	/* SysTick end of count event each 1ms */
-  	RCC_GetClocksFreq(&RCC_Clocks);
-  	SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);
-
-  	NVIC_SetPriority(SysTick_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(), 5, 5));
-}
-
-
-// for 100 MHz STM32F411
-#define COUNTS_PER_MICROSECOND	33
-void Delay_us(volatile uint32_t us)
-{
-	volatile uint32_t count = us * COUNTS_PER_MICROSECOND - 2;
-	__asm volatile(" mov r0, %[count]  \n\t"
-			"1: subs r0, #1            \n\t"
-			"   bhi 1b                 \n\t"
-			:
-			: [count] "r" (count)
-			: "r0");
-}
-
-
-void Delay_ms(volatile uint32_t ms)
-{
-	while(ms--)
-		Delay_us(999);
-}
-
 
 /******************************************************************************/
 /*            Cortex-M4 Processor Exceptions Handlers                         */
diff --git a/HAL/STM32/stm32f4xx_it.h b/HAL/STM32/stm32f4xx_it.h
index c3eca1e..a8e8c2a 100644
--- a/HAL/STM32/stm32f4xx_it.h
+++ b/HAL/STM32/stm32f4xx_it.h
@@ -42,10 +42,6 @@
 /* Exported macro ------------------------------------------------------------*/
 /* Exported functions ------------------------------------------------------- */
 
-void SysTick_Init(void);
-void Delay_us(volatile uint32_t us);
-void Delay_ms(volatile uint32_t ms);
-
 void NMI_Handler(void);
 void HardFault_Handler(void);
 void MemManage_Handler(void);
diff --git a/HAL/System32.c b/HAL/System32.c
index f1f4e13..1f277c1 100644
--- a/HAL/System32.c
+++ b/HAL/System32.c
@@ -15,6 +15,37 @@
   You should have received a copy of the GNU General Public License
   along with STM32F4_HAL.  If not, see <http://www.gnu.org/licenses/>.
 */
-#include "system.h"
+#include "System32.h"
 
 
+void SysTick_Init(void)
+{
+	RCC_ClocksTypeDef RCC_Clocks;
+
+	/* SysTick end of count event each 1ms */
+  	RCC_GetClocksFreq(&RCC_Clocks);
+  	SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);
+
+  	NVIC_SetPriority(SysTick_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(), 5, 5));
+}
+
+
+// for 100 MHz STM32F411
+#define COUNTS_PER_MICROSECOND	33
+void Delay_us(volatile uint32_t us)
+{
+	volatile uint32_t count = us * COUNTS_PER_MICROSECOND - 2;
+	__asm volatile(" mov r0, %[count]  \n\t"
+			"1: subs r0, #1            \n\t"
+			"   bhi 1b                 \n\t"
+			:
+			: [count] "r" (count)
+			: "r0");
+}
+
+
+void Delay_ms(volatile uint32_t ms)
+{
+	while(ms--)
+		Delay_us(999);
+}
diff --git a/HAL/System32.h b/HAL/System32.h
index 226e8db..87b0238 100644
--- a/HAL/System32.h
+++ b/HAL/System32.h
@@ -40,6 +40,12 @@ typedef struct {
 } Date_t;
 
 
+
+void SysTick_Init(void);
+void Delay_us(volatile uint32_t us);
+void Delay_ms(volatile uint32_t ms);
+
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/HAL/USART/FIFO_USART.c b/HAL/USART/FIFO_USART.c
index 1a8668b..32f2e5f 100644
--- a/HAL/USART/FIFO_USART.c
+++ b/HAL/USART/FIFO_USART.c
@@ -1,3 +1,21 @@
+/*
+  FIFO_USART.c - FIFO USART Implementation
+  Part of STM32F4_HAL
+
+  Copyright (c)	2016-2017 Patrick F.
+
+  STM32F4_HAL is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+  STM32F4_HAL is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+  You should have received a copy of the GNU General Public License
+  along with STM32F4_HAL.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
 /* Very simple queue
  * These are FIFO queues which discard the new data when full.
  *
@@ -8,7 +26,7 @@
  * Queue is full when in == (out-1 + QUEUE_SIZE) % QUEUE_SIZE;
  *
  * The queue will hold QUEUE_ELEMENTS number of items before the
- * calls to QueuePut fail.
+ * calls to FifoUsart_Insert fail.
  */
 #include <string.h>
 #include "FIFO_USART.h"
diff --git a/HAL/USART/FIFO_USART.h b/HAL/USART/FIFO_USART.h
index 556c52e..0125d8f 100644
--- a/HAL/USART/FIFO_USART.h
+++ b/HAL/USART/FIFO_USART.h
@@ -1,3 +1,20 @@
+/*
+  FIFO_USART.h - FIFO USART Header
+  Part of STM32F4_HAL
+
+  Copyright (c)	2016-2017 Patrick F.
+
+  STM32F4_HAL is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+  STM32F4_HAL is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+  You should have received a copy of the GNU General Public License
+  along with STM32F4_HAL.  If not, see <http://www.gnu.org/licenses/>.
+*/
 #ifndef FIFO_H_INCLUDED
 #define FIFO_H_INCLUDED
 
diff --git a/HAL/USART/USART.c b/HAL/USART/USART.c
index 9ff3215..685f665 100644
--- a/HAL/USART/USART.c
+++ b/HAL/USART/USART.c
@@ -1,5 +1,5 @@
 /*
-  Usart.c - Usart implementation
+  USART.c - USART implementation
   Part of STM32F4_HAL
 
   Copyright (c)	2017 Patrick F.
diff --git a/HAL/USART/USART.h b/HAL/USART/USART.h
index e655515..fc829b2 100644
--- a/HAL/USART/USART.h
+++ b/HAL/USART/USART.h
@@ -1,5 +1,5 @@
 /*
-  Usart.h - Usart Header
+  USART.h - USART Header
   Part of STM32F4_HAL
 
   Copyright (c)	2017 Patrick F.