diff --git a/boards/arduino-due/Makefile.features b/boards/arduino-due/Makefile.features
index 9be17cbb4b..4f578052e2 100644
--- a/boards/arduino-due/Makefile.features
+++ b/boards/arduino-due/Makefile.features
@@ -1 +1 @@
-FEATURES_PROVIDED += periph_gpio periph_spi periph_random
+FEATURES_PROVIDED += periph_uart periph_gpio periph_spi periph_random
diff --git a/boards/arduino-due/include/board.h b/boards/arduino-due/include/board.h
index 8344da85c1..f63fcda1d3 100644
--- a/boards/arduino-due/include/board.h
+++ b/boards/arduino-due/include/board.h
@@ -43,6 +43,7 @@ extern "C" {
  */
 #define STDIO               UART_0
 #define STDIO_BAUDRATE      (115200U)
+#define STDIO_RX_BUFSIZE    (64U)
 /** @} */
 
 /**
diff --git a/boards/arduino-due/include/periph_conf.h b/boards/arduino-due/include/periph_conf.h
index 4a27af3edb..464ca4702e 100644
--- a/boards/arduino-due/include/periph_conf.h
+++ b/boards/arduino-due/include/periph_conf.h
@@ -59,15 +59,17 @@ extern "C" {
  * @name UART configuration
  * @{
  */
-#define UART_NUMOF          (1U)
+#define UART_NUMOF          (4U)
 #define UART_0_EN           1
-#define UART_1_EN           0
-#define UART_2_EN           0
-#define UART_3_EN           0
+#define UART_1_EN           1
+#define UART_2_EN           1
+#define UART_3_EN           1
 #define UART_IRQ_PRIO       1
 
 /* UART 0 device configuration */
 #define UART_0_DEV          UART
+#define UART_0_CLKEN()      (PMC->PMC_PCER0 |= (1 << ID_UART))
+#define UART_0_CLKDIS()     (PMC->PMC_PCER0 &= ~(1 << ID_UART))
 #define UART_0_IRQ          UART_IRQn
 #define UART_0_ISR          isr_uart
 /* UART 0 pin configuration */
@@ -75,12 +77,34 @@ extern "C" {
 #define UART_0_PINS         (PIO_PA8 | PIO_PA9)
 
 /* UART 1 device configuration */
-#define UART_1_DEV
-#define UART_1_IRQ
-#define UART_1_ISR
+#define UART_1_DEV          USART0
+#define UART_1_CLKEN()      (PMC->PMC_PCER0 |= (1 << ID_USART0))
+#define UART_1_CLKDIS()     (PMC->PMC_PCER0 &= ~(1 << ID_USART0))
+#define UART_1_IRQ          USART0_IRQn
+#define UART_1_ISR          isr_usart0
 /* UART 1 pin configuration */
-#define UART_1_PORT
-#define UART_1_PINS
+#define UART_1_PORT         PIOA
+#define UART_1_PINS         (PIO_PA10 | PIO_PA11)
+
+/* UART 1 device configuration */
+#define UART_2_DEV          USART1
+#define UART_2_CLKEN()      (PMC->PMC_PCER0 |= (1 << ID_USART1))
+#define UART_2_CLKDIS()     (PMC->PMC_PCER0 &= ~(1 << ID_USART1))
+#define UART_2_IRQ          USART1_IRQn
+#define UART_2_ISR          isr_usart1
+/* UART 1 pin configuration */
+#define UART_2_PORT         PIOA
+#define UART_2_PINS         (PIO_PA12 | PIO_PA13)
+
+/* UART 1 device configuration */
+#define UART_3_DEV          USART3
+#define UART_3_CLKEN()      (PMC->PMC_PCER0 |= (1 << ID_USART3))
+#define UART_3_CLKDIS()     (PMC->PMC_PCER0 &= ~(1 << ID_USART3))
+#define UART_3_IRQ          USART3_IRQn
+#define UART_3_ISR          isr_usart3
+/* UART 1 pin configuration */
+#define UART_3_PORT         PIOD
+#define UART_3_PINS         (PIO_PD4 | PIO_PD5)
 /** @} */
 
 /**
diff --git a/boards/udoo/Makefile.features b/boards/udoo/Makefile.features
index 9be17cbb4b..4f578052e2 100644
--- a/boards/udoo/Makefile.features
+++ b/boards/udoo/Makefile.features
@@ -1 +1 @@
-FEATURES_PROVIDED += periph_gpio periph_spi periph_random
+FEATURES_PROVIDED += periph_uart periph_gpio periph_spi periph_random
diff --git a/boards/udoo/include/board.h b/boards/udoo/include/board.h
index 262f4af1b8..96c8a14af9 100644
--- a/boards/udoo/include/board.h
+++ b/boards/udoo/include/board.h
@@ -44,6 +44,7 @@ extern "C" {
  */
 #define STDIO               UART_0
 #define STDIO_BAUDRATE      (115200U)
+#define STDIO_RX_BUFSIZE    (64U)
 /** @} */
 
 /**
diff --git a/boards/udoo/include/periph_conf.h b/boards/udoo/include/periph_conf.h
index 5d4be8511e..c6e87101e4 100644
--- a/boards/udoo/include/periph_conf.h
+++ b/boards/udoo/include/periph_conf.h
@@ -58,15 +58,17 @@ extern "C" {
  * @name UART configuration
  * @{
  */
-#define UART_NUMOF          (1U)
+#define UART_NUMOF          (4U)
 #define UART_0_EN           1
-#define UART_1_EN           0
-#define UART_2_EN           0
-#define UART_3_EN           0
+#define UART_1_EN           1
+#define UART_2_EN           1
+#define UART_3_EN           1
 #define UART_IRQ_PRIO       1
 
 /* UART 0 device configuration */
 #define UART_0_DEV          UART
+#define UART_0_CLKEN()      (PMC->PMC_PCER0 |= (1 << ID_UART))
+#define UART_0_CLKDIS()     (PMC->PMC_PCER0 &= ~(1 << ID_UART))
 #define UART_0_IRQ          UART_IRQn
 #define UART_0_ISR          isr_uart
 /* UART 0 pin configuration */
@@ -74,12 +76,34 @@ extern "C" {
 #define UART_0_PINS         (PIO_PA8 | PIO_PA9)
 
 /* UART 1 device configuration */
-#define UART_1_DEV          USART2
-#define UART_1_IRQ          USART2_IRQn
-#define UART_1_ISR          isr_usart2
+#define UART_1_DEV          USART0
+#define UART_1_CLKEN()      (PMC->PMC_PCER0 |= (1 << ID_USART0))
+#define UART_1_CLKDIS()     (PMC->PMC_PCER0 &= ~(1 << ID_USART0))
+#define UART_1_IRQ          USART0_IRQn
+#define UART_1_ISR          isr_usart0
 /* UART 1 pin configuration */
-#define UART_1_PORT         GPIOA
-#define UART_1_PINS         (GPIO_Pin_2 | GPIO_Pin_3)
+#define UART_1_PORT         PIOA
+#define UART_1_PINS         (PIO_PA10 | PIO_PA11)
+
+/* UART 1 device configuration */
+#define UART_2_DEV          USART1
+#define UART_2_CLKEN()      (PMC->PMC_PCER0 |= (1 << ID_USART1))
+#define UART_2_CLKDIS()     (PMC->PMC_PCER0 &= ~(1 << ID_USART1))
+#define UART_2_IRQ          USART1_IRQn
+#define UART_2_ISR          isr_usart1
+/* UART 1 pin configuration */
+#define UART_2_PORT         PIOA
+#define UART_2_PINS         (PIO_PA12 | PIO_PA13)
+
+/* UART 1 device configuration */
+#define UART_3_DEV          USART3
+#define UART_3_CLKEN()      (PMC->PMC_PCER0 |= (1 << ID_USART3))
+#define UART_3_CLKDIS()     (PMC->PMC_PCER0 &= ~(1 << ID_USART3))
+#define UART_3_IRQ          USART3_IRQn
+#define UART_3_ISR          isr_usart3
+/* UART 1 pin configuration */
+#define UART_3_PORT         PIOD
+#define UART_3_PINS         (PIO_PD4 | PIO_PD5)
 /** @} */
 
 /**
diff --git a/cpu/sam3x8e/Makefile.include b/cpu/sam3x8e/Makefile.include
index 8c3e53c46a..c2467ca40a 100644
--- a/cpu/sam3x8e/Makefile.include
+++ b/cpu/sam3x8e/Makefile.include
@@ -1,13 +1,21 @@
-
 # this CPU implementation is using the new core/CPU interface
 export CFLAGS += -DCOREIF_NG=1
 
+# export the peripheral drivers to be linked into the final binary
+export USEMODULE += periph
+
+# this CPU implementation makes use of the ringbuffer, so include the lib module
+export USEMODULE += lib
+
 # tell the build system that the CPU depends on the Cortex-M common files
 export USEMODULE += cortex-m3_common
 
 # define path to cortex-m common module, which is needed for this CPU
 export CORTEX_COMMON = $(RIOTCPU)/cortex-m3_common/
 
+# CPU depends on the cortex-m common module, so include it
+include $(CORTEX_COMMON)Makefile.include
+
 # define the linker script to use for this CPU
 export LINKERSCRIPT ?= $(RIOTCPU)/$(CPU)/sam3x8e_linkerscript.ld
 
@@ -18,9 +26,3 @@ export INCLUDES += -I$(RIOTCPU)/$(CPU)/include
 #   Without this the interrupt vectors will not be linked correctly!
 export UNDEF += $(BINDIR)cpu/syscalls.o
 export UNDEF += $(BINDIR)cpu/startup.o
-
-# export the peripheral drivers to be linked into the final binary
-export USEMODULE += periph
-
-# CPU depends on the cortex-m common module, so include it
-include $(CORTEX_COMMON)Makefile.include
diff --git a/cpu/sam3x8e/periph/uart.c b/cpu/sam3x8e/periph/uart.c
index 886ba7bda8..f20a791576 100644
--- a/cpu/sam3x8e/periph/uart.c
+++ b/cpu/sam3x8e/periph/uart.c
@@ -20,10 +20,14 @@
 
 #include "board.h"
 #include "cpu.h"
-
+#include "sched.h"
+#include "thread.h"
 #include "periph/uart.h"
 #include "periph_conf.h"
 
+#define ENABLE_DEBUG (0)
+#include "debug.h"
+
 /* guard file in case no UART device was specified */
 #if UART_NUMOF
 
@@ -57,9 +61,34 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, uart_tx_cb_t t
 
     /* configure interrupts and enable RX interrupt */
     switch (uart) {
+#if UART_0_EN
         case UART_0:
+            NVIC_SetPriority(UART_0_IRQ, UART_IRQ_PRIO);
+            NVIC_EnableIRQ(UART_0_IRQ);
             UART_0_DEV->UART_IER = UART_IER_RXRDY;
-        break;
+            break;
+#endif
+#if UART_1_EN
+        case UART_1:
+            NVIC_SetPriority(UART_1_IRQ, UART_IRQ_PRIO);
+            NVIC_EnableIRQ(UART_1_IRQ);
+            UART_1_DEV->US_IER = US_IER_RXRDY;
+            break;
+#endif
+#if UART_2_EN
+        case UART_2:
+            NVIC_SetPriority(UART_2_IRQ, UART_IRQ_PRIO);
+            NVIC_EnableIRQ(UART_2_IRQ);
+            UART_2_DEV->US_IER = US_IER_RXRDY;
+            break;
+#endif
+#if UART_3_EN
+        case UART_3:
+            NVIC_SetPriority(UART_3_IRQ, UART_IRQ_PRIO);
+            NVIC_EnableIRQ(UART_3_IRQ);
+            UART_3_DEV->US_IER = US_IER_RXRDY;
+            break;
+#endif
     }
     return 0;
 }
@@ -67,12 +96,16 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, uart_tx_cb_t t
 int uart_init_blocking(uart_t uart, uint32_t baudrate)
 {
     uint16_t clock_divider = F_CPU / (16 * baudrate);
+
     switch (uart) {
 #if UART_0_EN
         case UART_0:
+            /* enable uart clock */
+            UART_0_CLKEN();
+
             /* configure PINS */
             UART_0_PORT->PIO_PDR = UART_0_PINS;
-            UART_0_PORT->PIO_ABSR &= ~UART_0_PINS;
+            UART_0_PORT->PIO_ABSR &= ~UART_0_PINS;      /* periph function A */
 
             /* set clock divider */
             UART_0_DEV->UART_BRGR = clock_divider;
@@ -81,6 +114,57 @@ int uart_init_blocking(uart_t uart, uint32_t baudrate)
             /* enable receiver and transmitter and reset status bits */
             UART_0_DEV->UART_CR = UART_CR_RXEN | UART_CR_TXEN | UART_CR_RSTSTA;
             break;
+#endif
+#if UART_1_EN
+        case UART_1:
+            /* enable uart clock */
+            UART_1_CLKEN();
+
+            /* configure PINS */
+            UART_1_PORT->PIO_PDR = UART_1_PINS;
+            UART_1_PORT->PIO_ABSR &= ~UART_1_PINS;      /* periph function A */
+
+            /* set clock divider */
+            UART_1_DEV->US_BRGR = clock_divider;
+            /* set to normal mode without parity */
+            UART_1_DEV->US_MR = US_MR_CHRL_8_BIT | US_MR_PAR_NO;
+            /* enable receiver and transmitter and reset status bits */
+            UART_1_DEV->US_CR = US_CR_RXEN | US_CR_TXEN | US_CR_RSTSTA;
+            break;
+#endif
+#if UART_2_EN
+        case UART_2:
+            /* enable uart clock */
+            UART_2_CLKEN();
+
+            /* configure PINS */
+            UART_2_PORT->PIO_PDR = UART_2_PINS;
+            UART_2_PORT->PIO_ABSR &= ~UART_2_PINS;      /* periph function A */
+
+            /* set clock divider */
+            UART_2_DEV->US_BRGR = clock_divider;
+            /* set to normal mode without parity */
+            UART_2_DEV->US_MR = US_MR_CHRL_8_BIT | US_MR_PAR_NO;
+            /* enable receiver and transmitter and reset status bits */
+            UART_2_DEV->US_CR = US_CR_RXEN | US_CR_TXEN | US_CR_RSTSTA;
+            break;
+#endif
+#if UART_3_EN
+        case UART_3:
+            /* enable uart clock */
+            UART_3_CLKEN();
+
+            /* configure PINS */
+            UART_3_PORT->PIO_PDR = UART_3_PINS;
+            UART_3_PORT->PIO_ABSR |= UART_3_PINS;       /* periph function B */
+
+            /* set clock divider */
+            UART_3_DEV->US_BRGR = clock_divider;
+            /* set to normal mode without parity */
+            UART_3_DEV->US_MR = US_MR_CHRL_8_BIT | US_MR_PAR_NO;
+            /* enable receiver and transmitter and reset status bits */
+            UART_3_DEV->US_CR = US_CR_RXEN | US_CR_TXEN | US_CR_RSTSTA;
+            break;
 #endif
     }
     return 0;
@@ -88,20 +172,53 @@ int uart_init_blocking(uart_t uart, uint32_t baudrate)
 
 void uart_tx_begin(uart_t uart)
 {
-
-}
-
-void uart_tx_end(uart_t uart)
-{
-
+    switch (uart) {
+#if UART_0_EN
+        case UART_0:
+            UART_0_DEV->UART_IER = UART_IER_TXRDY;
+            break;
+#endif
+#if UART_1_EN
+        case UART_1:
+            UART_1_DEV->US_IER = US_IER_TXRDY;
+            break;
+#endif
+#if UART_2_EN
+        case UART_2:
+            UART_2_DEV->US_IER = US_IER_TXRDY;
+            break;
+#endif
+#if UART_3_EN
+        case UART_3:
+            UART_3_DEV->US_IER = US_IER_TXRDY;
+            break;
+#endif
+    }
 }
 
 int uart_write(uart_t uart, char data)
 {
     switch (uart) {
+#if UART_0_EN
         case UART_0:
             UART_0_DEV->UART_THR = data;
             break;
+#endif
+#if UART_1_EN
+        case UART_1:
+            UART_1_DEV->US_THR = data;
+            break;
+#endif
+#if UART_2_EN
+        case UART_2:
+            UART_2_DEV->US_THR = data;
+            break;
+#endif
+#if UART_3_EN
+        case UART_3:
+            UART_3_DEV->US_THR = data;
+            break;
+#endif
     }
     return 1;
 }
@@ -109,33 +226,188 @@ int uart_write(uart_t uart, char data)
 int uart_read_blocking(uart_t uart, char *data)
 {
     switch (uart) {
+#if UART_0_EN
         case UART_0:
             while (!(UART_0_DEV->UART_SR & UART_SR_RXRDY));
             *data = (char)UART_0_DEV->UART_RHR;
             break;
+#endif
+#if UART_1_EN
+        case UART_1:
+            while (!(UART_1_DEV->US_CSR & US_CSR_RXRDY));
+            *data = (char)UART_1_DEV->US_RHR;
+            break;
+#endif
+#if UART_2_EN
+        case UART_2:
+            while (!(UART_2_DEV->US_CSR & US_CSR_RXRDY));
+            *data = (char)UART_2_DEV->US_RHR;
+            break;
+#endif
+#if UART_3_EN
+        case UART_3:
+            while (!(UART_3_DEV->US_CSR & US_CSR_RXRDY));
+            *data = (char)UART_3_DEV->US_RHR;
+            break;
+#endif
     }
+
     return 1;
 }
 
 int uart_write_blocking(uart_t uart, char data)
 {
     switch (uart) {
+#if UART_0_EN
         case UART_0:
             while (!(UART_0_DEV->UART_SR & UART_SR_TXRDY));
             UART_0_DEV->UART_THR = data;
             break;
+#endif
+#if UART_1_EN
+        case UART_1:
+            while(!(UART_1_DEV->US_CSR & US_CSR_TXRDY));
+            UART_1_DEV->US_THR = data;
+            break;
+#endif
+#if UART_2_EN
+        case UART_2:
+            while(!(UART_2_DEV->US_CSR & US_CSR_TXRDY));
+            UART_2_DEV->US_THR = data;
+            break;
+#endif
+#if UART_3_EN
+        case UART_3:
+            while(!(UART_3_DEV->US_CSR & US_CSR_TXRDY));
+            UART_3_DEV->US_THR = data;
+            break;
+#endif
     }
     return 1;
 }
 
 void uart_poweron(uart_t uart)
 {
-
+    switch (uart) {
+#if UART_0_EN
+        case UART_0:
+            UART_0_CLKEN();
+            break;
+#endif
+#if UART_1_EN
+        case UART_1:
+            UART_1_CLKEN();
+            break;
+#endif
+#if UART_2_EN
+        case UART_2:
+            UART_2_CLKEN();
+            break;
+#endif
+#if UART_3_EN
+        case UART_3:
+            UART_3_CLKEN();
+            break;
+#endif
+    }
 }
 
 void uart_poweroff(uart_t uart)
 {
-
+    switch (uart) {
+#if UART_0_EN
+        case UART_0:
+            UART_0_CLKDIS();
+            break;
+#endif
+#if UART_1_EN
+        case UART_1:
+            UART_1_CLKDIS();
+            break;
+#endif
+#if UART_2_EN
+        case UART_2:
+            UART_2_CLKDIS();
+            break;
+#endif
+#if UART_3_EN
+        case UART_3:
+            UART_3_CLKDIS();
+            break;
+#endif
+    }
 }
 
+#if UART_0_EN
+void UART_0_ISR(void)
+{
+    if (UART_0_DEV->UART_SR & UART_SR_RXRDY) {
+        char data = (char)UART_0_DEV->UART_RHR;
+        uart_config[UART_0].rx_cb(uart_config[UART_0].arg, data);
+    }
+    if ((UART_0_DEV->UART_SR & UART_SR_TXRDY) && (UART_0_DEV->UART_IMR & UART_IMR_TXRDY)) {
+        if (uart_config[UART_0].tx_cb(uart_config[UART_0].arg) == 0) {
+            UART_0_DEV->UART_IDR = UART_IDR_TXRDY;
+        }
+    }
+    if (sched_context_switch_request) {
+        thread_yield();
+    }
+}
+#endif
+
+#if UART_1_EN
+void UART_1_ISR(void)
+{
+    if (UART_1_DEV->US_CSR & US_CSR_RXRDY) {
+        char data = (char)UART_1_DEV->US_RHR;
+        uart_config[UART_1].rx_cb(uart_config[UART_1].arg, data);
+    }
+    if ((UART_1_DEV->US_CSR & US_CSR_TXRDY) && (UART_1_DEV->US_IMR & US_IMR_TXRDY)) {
+        if (uart_config[UART_1].tx_cb(uart_config[UART_1].arg) == 0) {
+            UART_1_DEV->US_IDR = US_IDR_TXRDY;
+        }
+    }
+    if (sched_context_switch_request) {
+        thread_yield();
+    }
+}
+#endif
+
+#if UART_2_EN
+void UART_2_ISR(void)
+{
+    if (UART_2_DEV->US_CSR & US_CSR_RXRDY) {
+        char data = (char)UART_2_DEV->US_RHR;
+        uart_config[UART_2].rx_cb(uart_config[UART_2].arg, data);
+    }
+    if ((UART_2_DEV->US_CSR & US_CSR_TXRDY) && (UART_2_DEV->US_IMR & US_IMR_TXRDY)) {
+        if (uart_config[UART_2].tx_cb(uart_config[UART_2].arg) == 0) {
+            UART_2_DEV->US_IDR = US_IDR_TXRDY;
+        }
+    }
+    if (sched_context_switch_request) {
+        thread_yield();
+    }
+}
+#endif
+
+#if UART_3_EN
+void UART_3_ISR(void)
+{
+    if (UART_3_DEV->US_CSR & US_CSR_RXRDY) {
+        char data = (char)UART_3_DEV->US_RHR;
+        uart_config[UART_3].rx_cb(uart_config[UART_3].arg, data);
+    }
+    if ((UART_3_DEV->US_CSR & US_CSR_TXRDY) && (UART_3_DEV->US_IMR & US_IMR_TXRDY)) {
+        if (uart_config[UART_3].tx_cb(uart_config[UART_3].arg) == 0) {
+            UART_3_DEV->US_IDR = US_IDR_TXRDY;
+        }
+    }
+    if (sched_context_switch_request) {
+        thread_yield();
+    }
+}
+#endif
+
 #endif /* UART_NUMOF */
diff --git a/cpu/sam3x8e/syscalls.c b/cpu/sam3x8e/syscalls.c
index 0b5aacdecf..f060896592 100644
--- a/cpu/sam3x8e/syscalls.c
+++ b/cpu/sam3x8e/syscalls.c
@@ -31,21 +31,60 @@
 #include "board.h"
 #include "thread.h"
 #include "kernel.h"
+#include "mutex.h"
+#include "ringbuffer.h"
 #include "irq.h"
 #include "periph/uart.h"
 
+#ifdef MODULE_UART0
+#include "board_uart0.h"
+#endif
+
 /**
  * manage the heap
  */
 extern char _sheap;                 /* start of the heap */
 extern char _eheap;                 /* end of the heap */
 caddr_t heap_top = (caddr_t)&_sheap + 4;
+
+#ifndef MODULE_UART0
+/**
+ * @brief use mutex for waiting on incoming UART chars
+ */
+static mutex_t uart_rx_mutex;
+static char rx_buf_mem[STDIO_RX_BUFSIZE];
+static ringbuffer_t rx_buf;
+#endif
+
+/**
+ * @brief Receive a new character from the UART and put it into the receive buffer
+ */
+void rx_cb(void *arg, char data)
+{
+#ifndef MODULE_UART0
+    (void)arg;
+
+    ringbuffer_add_one(&rx_buf, data);
+    mutex_unlock(&uart_rx_mutex);
+#else
+    if (uart0_handler_pid) {
+        uart0_handle_incoming(data);
+
+        uart0_notify_thread();
+    }
+#endif
+}
+
 /**
  * @brief Initialize NewLib, called by __libc_init_array() from the startup script
  */
 void _init(void)
 {
-    uart_init_blocking(STDIO, STDIO_BAUDRATE);
+#ifndef MODULE_UART0
+    mutex_init(&uart_rx_mutex);
+    ringbuffer_init(&rx_buf, rx_buf_mem, STDIO_RX_BUFSIZE);
+#endif
+    uart_init(STDIO, STDIO_BAUDRATE, rx_cb, 0, 0);
 }
 
 /**
@@ -157,11 +196,16 @@ int _open_r(struct _reent *r, const char *name, int mode)
  */
 int _read_r(struct _reent *r, int fd, void *buffer, unsigned int count)
 {
-    char c;
-    char *buff = (char*)buffer;
-    uart_read_blocking(UART_0, &c);
-    buff[0] = c;
+#ifndef MODULE_UART0
+    while (rx_buf.avail == 0) {
+        mutex_lock(&uart_rx_mutex);
+    }
+    return ringbuffer_get(&rx_buf, (char*)buffer, rx_buf.avail);
+#else
+    char *res = (char*)buffer;
+    res[0] = (char)uart0_readc();
     return 1;
+#endif
 }
 
 /**
@@ -181,9 +225,8 @@ int _read_r(struct _reent *r, int fd, void *buffer, unsigned int count)
  */
 int _write_r(struct _reent *r, int fd, const void *data, unsigned int count)
 {
-    char *c = (char*)data;
     for (int i = 0; i < count; i++) {
-        uart_write_blocking(UART_0, c[i]);
+        uart_write_blocking(UART_0, ((char *)data)[i]);
     }
     return count;
 }