diff --git a/cpu/atmega_common/periph/uart.c b/cpu/atmega_common/periph/uart.c
index 4449ab2bf6..1f4ebb30be 100644
--- a/cpu/atmega_common/periph/uart.c
+++ b/cpu/atmega_common/periph/uart.c
@@ -36,19 +36,20 @@
 
 
 /**
- * @brief  Maximum percentage error in calculated baud before switching to double speed transmission (U2X)
+ * @brief   Maximum percentage error in calculated baud before switching to
+ *          double speed transmission (U2X)
  *
  * Takes whole numbers from 0 to 100, inclusive, with a default of 2.
  */
 #if defined(UART_BAUD_TOL)
-// BAUD_TOL is defined here as it is used by the setbaud.h utility
+/* BAUD_TOL is defined here as it is used by the setbaud.h utility */
 #define BAUD_TOL UART_BAUD_TOL
 #else
 #define BAUD_TOL 2
 #endif
 
 #if defined(UART_STDIO_BAUDRATE)
-// BAUD and F_CPU are required by setbaud.h to calculated BRR
+/* BAUD and F_CPU are required by setbaud.h to calculated BRR */
 #define BAUD UART_STDIO_BAUDRATE
 #define F_CPU CLOCK_CORECLOCK
 #include <util/setbaud.h>
@@ -129,8 +130,15 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
     dev[uart]->CSRC = (1 << UCSZ00) | (1 << UCSZ01);
     /* set clock divider */
     _set_brr(uart, baudrate);
+
     /* enable RX and TX and the RX interrupt */
-    dev[uart]->CSRB = ((1 << RXCIE0) | (1 << RXEN0) | (1 << TXEN0));
+    if (rx_cb) {
+        dev[uart]->CSRB = ((1 << RXCIE0) | (1 << RXEN0) | (1 << TXEN0));
+    }
+    else {
+        dev[uart]->CSRB = (1 << TXEN0);
+    }
+
 
     return UART_OK;
 }
diff --git a/cpu/ezr32wg/periph/uart.c b/cpu/ezr32wg/periph/uart.c
index 75d620070c..37d17d2df7 100644
--- a/cpu/ezr32wg/periph/uart.c
+++ b/cpu/ezr32wg/periph/uart.c
@@ -65,16 +65,26 @@ int uart_init(uart_t dev, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
      * the division afterwards... */
     uart->CLKDIV = (((CLOCK_HFPERCLK << 5) / (16 * baudrate) - 32) << 3);
     /* configure the pins */
-    gpio_init(uart_config[dev].rx_pin, GPIO_IN);
     gpio_init(uart_config[dev].tx_pin, GPIO_OUT);
-    uart->ROUTE = ((uart_config[dev].loc << _USART_ROUTE_LOCATION_SHIFT) |
-                   USART_ROUTE_RXPEN | USART_ROUTE_TXPEN);
-    /* enable RX interrupt */
-    NVIC_EnableIRQ(uart_config[dev].irq);
-    NVIC_EnableIRQ(uart_config[dev].irq + 1);
-    uart->IEN |= USART_IEN_RXDATAV;
-    /* enable receiver and transmitter */
-    uart->CMD = USART_CMD_TXEN | USART_CMD_RXEN;
+    if (rx_cb) {
+        gpio_init(uart_config[dev].rx_pin, GPIO_IN);
+        uart->ROUTE = ((uart_config[dev].loc << _USART_ROUTE_LOCATION_SHIFT) |
+                       USART_ROUTE_RXPEN | USART_ROUTE_TXPEN);
+    } else {
+        uart->ROUTE = ((uart_config[dev].loc << _USART_ROUTE_LOCATION_SHIFT) |
+                       USART_ROUTE_TXPEN);
+    }
+    if (rx_cb) {
+        /* enable RX interrupt */
+        NVIC_EnableIRQ(uart_config[dev].irq);
+        NVIC_EnableIRQ(uart_config[dev].irq + 1);
+        uart->IEN |= USART_IEN_RXDATAV;
+        /* enable receiver and transmitter */
+        uart->CMD = USART_CMD_TXEN | USART_CMD_RXEN;
+    }
+    else {
+        uart->CMD = USART_CMD_TXEN;
+    }
     return UART_OK;
 }
 
diff --git a/cpu/nrf5x_common/periph/uart.c b/cpu/nrf5x_common/periph/uart.c
index 2544d5c093..2c8a6dd11c 100644
--- a/cpu/nrf5x_common/periph/uart.c
+++ b/cpu/nrf5x_common/periph/uart.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014-2016 Freie Universität Berlin
+ * Copyright (C) 2014-2017 Freie Universität Berlin
  *               2015 Jan Wagner <mail@jwagner.eu>
  *
  *
@@ -50,14 +50,20 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
    /* power on the UART device */
     NRF_UART0->POWER = 1;
 #endif
+
     /* reset configuration registers */
     NRF_UART0->CONFIG = 0;
-    /* configure RX/TX pin modes */
+
+    /* configure RX pin */
+    if (rx_cb) {
+        GPIO_BASE->DIRCLR = (1 << UART_PIN_RX);
+        NRF_UART0->PSELRXD = UART_PIN_RX;
+    }
+
+    /* configure TX pin */
     GPIO_BASE->DIRSET = (1 << UART_PIN_TX);
-    GPIO_BASE->DIRCLR = (1 << UART_PIN_RX);
-    /* configure UART pins to use */
     NRF_UART0->PSELTXD = UART_PIN_TX;
-    NRF_UART0->PSELRXD = UART_PIN_RX;
+
     /* enable HW-flow control if defined */
 #if UART_HWFLOWCTRL
     /* set pin mode for RTS and CTS pins */
@@ -127,10 +133,14 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
     NRF_UART0->ENABLE = UART_ENABLE_ENABLE_Enabled;
     /* enable TX and RX */
     NRF_UART0->TASKS_STARTTX = 1;
-    NRF_UART0->TASKS_STARTRX = 1;
-    /* enable global and receiving interrupt */
-    NVIC_EnableIRQ(UART_IRQN);
-    NRF_UART0->INTENSET = UART_INTENSET_RXDRDY_Msk;
+
+    if (rx_cb) {
+        NRF_UART0->TASKS_STARTRX = 1;
+        /* enable global and receiving interrupt */
+        NVIC_EnableIRQ(UART_IRQN);
+        NRF_UART0->INTENSET = UART_INTENSET_RXDRDY_Msk;
+    }
+
     return UART_OK;
 }
 
diff --git a/cpu/stm32_common/periph/uart.c b/cpu/stm32_common/periph/uart.c
index e94107bf98..5d04bcf827 100644
--- a/cpu/stm32_common/periph/uart.c
+++ b/cpu/stm32_common/periph/uart.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014-2016 Freie Universität Berlin
+ * Copyright (C) 2014-2017 Freie Universität Berlin
  * Copyright (C) 2016 OTA keys
  *
  * This file is subject to the terms and conditions of the GNU Lesser
@@ -8,7 +8,7 @@
  */
 
 /**
- * @ingroup     cpu_stm32f2
+ * @ingroup     cpu_stm32_common
  * @{
  *
  * @file
@@ -56,8 +56,7 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
     isr_ctx[uart].rx_cb = rx_cb;
     isr_ctx[uart].arg   = arg;
 
-    /* configure RX and TX pin */
-    gpio_init(uart_config[uart].rx_pin, GPIO_IN);
+    /* configure TX pin */
     gpio_init(uart_config[uart].tx_pin, GPIO_OUT);
     /* set TX pin high to avoid garbage during further initialization */
     gpio_set(uart_config[uart].tx_pin);
@@ -65,8 +64,14 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
     gpio_init_af(uart_config[uart].tx_pin, GPIO_AF_OUT_PP);
 #else
     gpio_init_af(uart_config[uart].tx_pin, uart_config[uart].tx_af);
-    gpio_init_af(uart_config[uart].rx_pin, uart_config[uart].rx_af);
 #endif
+    /* configure RX pin */
+    if (rx_cb) {
+        gpio_init(uart_config[uart].rx_pin, GPIO_IN);
+#ifndef CPU_FAM_STM32F1
+        gpio_init_af(uart_config[uart].rx_pin, uart_config[uart].rx_af);
+#endif
+    }
 
     /* enable the clock */
     periph_clk_en(uart_config[uart].bus, uart_config[uart].rcc_mask);
diff --git a/drivers/include/periph/uart.h b/drivers/include/periph/uart.h
index 7ef5e0ad4a..17f6649295 100644
--- a/drivers/include/periph/uart.h
+++ b/drivers/include/periph/uart.h
@@ -124,10 +124,14 @@ enum {
  * - 1 stop bit
  * - baudrate as given
  *
+ * If no callback parameter is given (rx_cb := NULL), the UART will be
+ * initialized in TX only mode.
+ *
  * @param[in] uart          UART device to initialize
  * @param[in] baudrate      desired baudrate in baud/s
  * @param[in] rx_cb         receive callback, executed in interrupt context once
- *                          for every byte that is received (RX buffer filled)
+ *                          for every byte that is received (RX buffer filled),
+ *                          set to NULL for TX only mode
  * @param[in] arg           optional context passed to the callback functions
  *
  * @return                  UART_OK on success