diff --git a/drivers/usart.c b/drivers/usart.c
index 017df30..0b8406c 100644
--- a/drivers/usart.c
+++ b/drivers/usart.c
@@ -12,6 +12,9 @@
 #include "reg.h"
 
 #include "rcc.h"
+#include "dma.h"
+
+#include "stddef.h"
 
 
 //--local definitions-----------------------------------------------------------
@@ -20,14 +23,23 @@ static volatile struct USART* const usart1 = (struct USART*)USART1_BASE_ADDRESS;
 static volatile struct USART* const usart2 = (struct USART*)USART2_BASE_ADDRESS;
 static volatile struct USART* const usart3 = (struct USART*)USART3_BASE_ADDRESS;
 
-void configure_usart(volatile struct USART* regs, enum UsartConfig config);
-void configure_baudrate(volatile struct USART* regs, uint32_t clock,
+static void configure_usart(volatile struct USART* regs,
+		enum UsartConfig config);
+static void configure_baudrate(volatile struct USART* regs, uint32_t clock,
 		uint32_t baudrate);
-uint32_t periph_regs(enum UsartPeriph periph, volatile struct USART** regs);
+static uint32_t periph_regs(enum UsartPeriph periph,
+		volatile struct USART** regs);
+static uint32_t read_from_buffer(volatile uint8_t* buffer,
+		enum DmaChannel channel, uint8_t* byte);
+
+static void usart1_rx_callback(enum DmaIRQSource src);
 
 
 //--local variables-------------------------------------------------------------
 
+static volatile uint8_t* usart1_rx_buffer;
+
+
 //--public functions------------------------------------------------------------
 
 void usart_configure(enum UsartPeriph periph, enum UsartConfig config,
@@ -75,21 +87,58 @@ uint32_t usart_write_byte(enum UsartPeriph periph, uint8_t byte)
 uint32_t usart_read_byte(enum UsartPeriph periph, uint8_t* byte)
 {
 	volatile struct USART* regs;
-	if (periph_regs(periph, &regs)) {
-		return 1;
+	volatile uint8_t* buffer;
+	enum DmaChannel dma_channel;
+
+	switch (periph) {
+		case USART_PERIPH_1:
+			regs = usart1;
+			buffer = usart1_rx_buffer;
+			dma_channel = DMA_CHANNEL_5;
+			break;
+		case USART_PERIPH_2:
+		case USART_PERIPH_3:
+		default:
+			return 1;
+			break;
 	}
 
-	if (regs->SR.RXNE) {
-		*byte = regs->DR.DR;
-		return 0;
+	if (buffer) {
+		return read_from_buffer(buffer, dma_channel, byte);
 	} else {
-		return 1;
+		if (regs->SR.RXNE) {
+			*byte = regs->DR.DR;
+			return 0;
+		} else {
+			return 1;
+		}
+	}
+}
+
+void usart_set_rx_buffer(enum UsartPeriph periph, uint8_t* buffer,
+		uint16_t size)
+{
+	switch (periph) {
+		case USART_PERIPH_1:
+			dma_configure(DMA_PERIPH_1, DMA_CHANNEL_5,
+					DMA_CONFIG_IRQ_COMPLETE | DMA_CONFIG_FROM_PERIPH
+					| DMA_CONFIG_CIRCULAR | DMA_CONFIG_INC_MEM
+					| DMA_CONFIG_PSIZE_8BITS | DMA_CONFIG_MSIZE_8BITS
+					| DMA_CONFIG_PRIO_LOW, (void*)&usart1->DR, buffer,
+					size, usart1_rx_callback);
+			usart1_rx_buffer = buffer;
+			reg_set(usart1->CR3, USART_CR3_DMAR);
+			break;
+		case USART_PERIPH_2:
+			break;
+		case USART_PERIPH_3:
+			break;
 	}
 }
 
 //--local functions-------------------------------------------------------------
 
-void configure_usart(volatile struct USART* regs, enum UsartConfig config)
+static void configure_usart(volatile struct USART* regs, enum UsartConfig config)
 {
 	//configure parity
 	switch (config)
@@ -165,7 +214,7 @@ void configure_usart(volatile struct USART* regs, enum UsartConfig config)
 	reg_set(regs->CR1, USART_CR1_UE);
 }
 
-void configure_baudrate(volatile struct USART* regs, uint32_t clock,
+static void configure_baudrate(volatile struct USART* regs, uint32_t clock,
 		uint32_t baudrate)
 {
 	uint32_t mantissa = clock / (baudrate * 16);
@@ -178,7 +227,7 @@ void configure_baudrate(volatile struct USART* regs, uint32_t clock,
 	reg_write(regs->BRR, USART_BRR_DIV_Fraction, divider & 0xF);
 }
 
-uint32_t periph_regs(enum UsartPeriph periph, volatile struct USART** regs)
+static uint32_t periph_regs(enum UsartPeriph periph, volatile struct USART** regs)
 {
 	switch (periph) {
 		case USART_PERIPH_1:
@@ -198,3 +247,16 @@ uint32_t periph_regs(enum UsartPeriph periph, volatile struct USART** regs)
 	return 0;
 }
 
+static uint32_t read_from_buffer(volatile uint8_t* buffer,
+		enum DmaChannel channel, uint8_t* byte)
+{
+
+}
+
+//--callbacks-------------------------------------------------------------------
+
+static void usart1_rx_callback(enum DmaIRQSource src)
+{
+
+}
+
diff --git a/drivers/usart.h b/drivers/usart.h
index c5845c1..ed68b3f 100644
--- a/drivers/usart.h
+++ b/drivers/usart.h
@@ -46,6 +46,12 @@ uint32_t usart_write_byte(enum UsartPeriph periph, uint8_t byte);
 
 uint32_t usart_read_byte(enum UsartPeriph periph, uint8_t* byte);
 
+void usart_set_tx_buffer(enum UsartPeriph periph, uint8_t* buffer,
+		uint16_t size);
+
+void usart_set_rx_buffer(enum UsartPeriph periph, uint8_t* buffer,
+		uint16_t size);
+
 
 #endif //_USART_H_