diff --git a/include/libopenstm32.h b/include/libopenstm32.h
index dfe3bd6e..e9221ae5 100644
--- a/include/libopenstm32.h
+++ b/include/libopenstm32.h
@@ -24,5 +24,6 @@
 #include <libopenstm32/memorymap.h>
 #include <libopenstm32/rcc.h>
 #include <libopenstm32/gpio.h>
+#include <libopenstm32/usart.h>
 
 #endif
diff --git a/include/libopenstm32/usart.h b/include/libopenstm32/usart.h
new file mode 100644
index 00000000..9037e791
--- /dev/null
+++ b/include/libopenstm32/usart.h
@@ -0,0 +1,85 @@
+/*
+ * This file is part of the libopenstm32 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef LIBOPENSTM32_USART_H
+#define LIBOPENSTM32_USART_H
+
+#include <libopenstm32.h>
+
+/* --- USART registers ----------------------------------------------------- */
+
+#define USART_SR			MMIO32(USART_BASE + 0x00)
+#define USART_DR			MMIO32(USART_BASE + 0x04)
+#define USART_BRR			MMIO32(USART_BASE + 0x08)
+#define USART_CR1			MMIO32(USART_BASE + 0x0c)
+#define USART_CR2			MMIO32(USART_BASE + 0x10)
+#define USART_CR3			MMIO32(USART_BASE + 0x14)
+#define USART_GTPR			MMIO32(USART_BASE + 0x18)
+
+/* --- RCC_SR values ------------------------------------------------------- */
+
+#define SR_CTS				(1 << 9)
+#define SR_LBD				(1 << 8)
+#define SR_TXE				(1 << 7)
+#define SR_TC				(1 << 6)
+#define SR_RXNE				(1 << 5)
+#define SR_IDLE				(1 << 4)
+#define SR_ORE				(1 << 3)
+#define SR_NE				(1 << 2)
+#define SR_FE				(1 << 1)
+#define SR_PE				(1 << 0)
+
+/* --- RCC_DR values ------------------------------------------------------- */
+
+/* DR[8:0]: Data value */
+
+/* --- RCC_BRR values ------------------------------------------------------ */
+
+/* TODO */
+
+/* --- RCC_CR1 values ------------------------------------------------------ */
+
+#define CR1_UE				(1 << 13)
+#define CR1_M				(1 << 12)
+#define CR1_WAKE			(1 << 11)
+#define CR1_PCE				(1 << 10)
+#define CR1_PS				(1 << 9)
+#define CR1_PEIE			(1 << 8)
+#define CR1_TXEIE			(1 << 7)
+#define CR1_TCIE			(1 << 6)
+#define CR1_RXNEIE			(1 << 5)
+#define CR1_IDLEIE			(1 << 4)
+#define CR1_TE				(1 << 3)
+#define CR1_RE				(1 << 2)
+#define CR1_RWU				(1 << 1)
+#define CR1_SBK				(1 << 0)
+
+/* --- RCC_CR2 values ------------------------------------------------------ */
+
+/* TODO */
+
+/* --- RCC_CR3 values ------------------------------------------------------ */
+
+/* TODO */
+
+/* --- RCC_GTPR values ----------------------------------------------------- */
+
+/* TODO */
+
+#endif
diff --git a/lib/Makefile b/lib/Makefile
index aaad7293..a3f66f1a 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -27,7 +27,7 @@ CFLAGS		= -Os -g -Wall -Wextra -I../include -fno-common \
 		  -mcpu=cortex-m3 -mthumb -Wstrict-prototypes
 # ARFLAGS	= rcsv
 ARFLAGS		= rcs
-OBJS		= gpio.o rcc.o
+OBJS		= rcc.o gpio.o usart.o
 
 # Be silent per default, but 'make V=1' will show all compiler calls.
 ifneq ($(V),1)
diff --git a/lib/usart.c b/lib/usart.c
new file mode 100644
index 00000000..02edd86e
--- /dev/null
+++ b/lib/usart.c
@@ -0,0 +1,23 @@
+/*
+ * This file is part of the libopenstm32 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopenstm32.h>
+
+/* TODO */
+