diff --git a/boards/arduino-mkr-common/include/periph_conf.h b/boards/arduino-mkr-common/include/periph_conf.h
index 6fc69bec0d..a538729ad6 100644
--- a/boards/arduino-mkr-common/include/periph_conf.h
+++ b/boards/arduino-mkr-common/include/periph_conf.h
@@ -104,12 +104,14 @@ extern "C" {
  */
 static const uart_conf_t uart_config[] = {
     {
-        .dev    = &SERCOM5->USART,
-        .rx_pin = GPIO_PIN(PB,23),  /* ARDUINO_PIN_13, RX Pin */
-        .tx_pin = GPIO_PIN(PB,22),  /* ARDUINO_PIN_14, TX Pin */
-        .mux    = GPIO_MUX_D,
-        .rx_pad = UART_PAD_RX_3,
-        .tx_pad = UART_PAD_TX_2
+        .dev      = &SERCOM5->USART,
+        .rx_pin   = GPIO_PIN(PB,23),  /* ARDUINO_PIN_13, RX Pin */
+        .tx_pin   = GPIO_PIN(PB,22),  /* ARDUINO_PIN_14, TX Pin */
+        .mux      = GPIO_MUX_D,
+        .rx_pad   = UART_PAD_RX_3,
+        .tx_pad   = UART_PAD_TX_2,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     }
 };
 
diff --git a/boards/arduino-zero/include/periph_conf.h b/boards/arduino-zero/include/periph_conf.h
index 773ada0dd2..a34cd81e83 100644
--- a/boards/arduino-zero/include/periph_conf.h
+++ b/boards/arduino-zero/include/periph_conf.h
@@ -107,20 +107,24 @@ extern "C" {
  */
 static const uart_conf_t uart_config[] = {
     {
-        .dev    = &SERCOM5->USART,
-        .rx_pin = GPIO_PIN(PB,23),
-        .tx_pin = GPIO_PIN(PB,22),
-        .mux    = GPIO_MUX_D,
-        .rx_pad = UART_PAD_RX_3,
-        .tx_pad = UART_PAD_TX_2
+        .dev      = &SERCOM5->USART,
+        .rx_pin   = GPIO_PIN(PB,23),
+        .tx_pin   = GPIO_PIN(PB,22),
+        .mux      = GPIO_MUX_D,
+        .rx_pad   = UART_PAD_RX_3,
+        .tx_pad   = UART_PAD_TX_2,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     },
     {
-        .dev    = &SERCOM0->USART,
-        .rx_pin = GPIO_PIN(PA,11),
-        .tx_pin = GPIO_PIN(PA,10),
-        .mux    = GPIO_MUX_C,
-        .rx_pad = UART_PAD_RX_3,
-        .tx_pad = UART_PAD_TX_2
+        .dev      = &SERCOM0->USART,
+        .rx_pin   = GPIO_PIN(PA,11),
+        .tx_pin   = GPIO_PIN(PA,10),
+        .mux      = GPIO_MUX_C,
+        .rx_pad   = UART_PAD_RX_3,
+        .tx_pad   = UART_PAD_TX_2,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     }
 };
 
diff --git a/boards/samd21-xpro/include/periph_conf.h b/boards/samd21-xpro/include/periph_conf.h
index 33a080b404..02e138ae64 100644
--- a/boards/samd21-xpro/include/periph_conf.h
+++ b/boards/samd21-xpro/include/periph_conf.h
@@ -112,12 +112,14 @@ extern "C" {
  */
 static const uart_conf_t uart_config[] = {
     {    /* Virtual COM Port */
-        .dev    = &SERCOM3->USART,
-        .rx_pin = GPIO_PIN(PA,23),
-        .tx_pin = GPIO_PIN(PA,22),
-        .mux    = GPIO_MUX_C,
-        .rx_pad = UART_PAD_RX_1,
-        .tx_pad = UART_PAD_TX_0
+        .dev      = &SERCOM3->USART,
+        .rx_pin   = GPIO_PIN(PA,23),
+        .tx_pin   = GPIO_PIN(PA,22),
+        .mux      = GPIO_MUX_C,
+        .rx_pad   = UART_PAD_RX_1,
+        .tx_pad   = UART_PAD_TX_0,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     },
     {    /* EXT1 */
         .dev    = &SERCOM4->USART,
@@ -125,7 +127,9 @@ static const uart_conf_t uart_config[] = {
         .tx_pin = GPIO_PIN(PB,8),
         .mux    = GPIO_MUX_D,
         .rx_pad = UART_PAD_RX_1,
-        .tx_pad = UART_PAD_TX_0
+        .tx_pad = UART_PAD_TX_0,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     },
     {    /* EXT2/3 */
         .dev    = &SERCOM4->USART,
@@ -133,7 +137,9 @@ static const uart_conf_t uart_config[] = {
         .tx_pin = GPIO_PIN(PB,10),
         .mux    = GPIO_MUX_D,
         .rx_pad = UART_PAD_RX_3,
-        .tx_pad = UART_PAD_TX_2
+        .tx_pad = UART_PAD_TX_2,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     }
 };
 
diff --git a/boards/saml21-xpro/include/periph_conf.h b/boards/saml21-xpro/include/periph_conf.h
index 2a06a98398..d3b77a23b0 100644
--- a/boards/saml21-xpro/include/periph_conf.h
+++ b/boards/saml21-xpro/include/periph_conf.h
@@ -52,22 +52,34 @@ extern "C" {
  * @name    UART configuration
  * @{
  */
-#define UART_NUMOF          (1U)
-#define UART_0_EN           1
-#define UART_IRQ_PRIO       1
+static const uart_conf_t uart_config[] = {
+    {    /* Virtual COM Port */
+        .dev      = &SERCOM3->USART,
+        .rx_pin   = GPIO_PIN(PA,23),
+        .tx_pin   = GPIO_PIN(PA,22),
+        .mux      = GPIO_MUX_C,
+        .rx_pad   = UART_PAD_RX_1,
+        .tx_pad   = UART_PAD_TX_0,
+        .runstdby = 0,
+        .gclk_src = GCLK_PCHCTRL_GEN_GCLK0
+    },
+    {    /* EXT1 header */
+        .dev      = &SERCOM4->USART,
+        .rx_pin   = GPIO_PIN(PB, 9),
+        .tx_pin   = GPIO_PIN(PB, 8),
+        .mux      = GPIO_MUX_D,
+        .rx_pad   = UART_PAD_RX_1,
+        .tx_pad   = UART_PAD_TX_0,
+        .runstdby = 0,
+        .gclk_src = GCLK_PCHCTRL_GEN_GCLK0
+    }
+};
 
-/* UART 0 device configuration */
-#define UART_0_DEV          SERCOM3->USART
-#define UART_0_IRQ          SERCOM3_IRQn
+/* interrupt function name mapping */
 #define UART_0_ISR          isr_sercom3
-#define UART_0_REF_F        (16000000UL)
-#define UART_0_RUNSTDBY     1
+#define UART_1_ISR          isr_sercom4
 
-/* UART 0 pin configuration */
-#define UART_0_PORT         (PORT->Group[0])
-#define UART_0_TX_PIN       (22)
-#define UART_0_RX_PIN       (23)
-#define UART_0_PINS         (((PORT_PA22 | PORT_PA23) >> 16) | PORT_WRCONFIG_HWSEL)
+#define UART_NUMOF          (sizeof(uart_config) / sizeof(uart_config[0]))
 /** @} */
 
 /**
diff --git a/boards/samr21-xpro/include/periph_conf.h b/boards/samr21-xpro/include/periph_conf.h
index aae2a47786..18881a5b85 100644
--- a/boards/samr21-xpro/include/periph_conf.h
+++ b/boards/samr21-xpro/include/periph_conf.h
@@ -117,7 +117,9 @@ static const uart_conf_t uart_config[] = {
         .tx_pin = GPIO_PIN(PA,4),
         .mux    = GPIO_MUX_D,
         .rx_pad = UART_PAD_RX_1,
-        .tx_pad = UART_PAD_TX_0
+        .tx_pad = UART_PAD_TX_0,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     },
     {
         .dev    = &SERCOM5->USART,
@@ -125,7 +127,9 @@ static const uart_conf_t uart_config[] = {
         .tx_pin = GPIO_PIN(PA,22),
         .mux    = GPIO_MUX_D,
         .rx_pad = UART_PAD_RX_1,
-        .tx_pad = UART_PAD_TX_0
+        .tx_pad = UART_PAD_TX_0,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     }
 };
 
diff --git a/boards/sodaq-autonomo/include/periph_conf.h b/boards/sodaq-autonomo/include/periph_conf.h
index c4a272ef52..e8e77dbcaf 100644
--- a/boards/sodaq-autonomo/include/periph_conf.h
+++ b/boards/sodaq-autonomo/include/periph_conf.h
@@ -103,36 +103,44 @@ extern "C" {
  */
 static const uart_conf_t uart_config[] = {
     {
-        .dev    = &SERCOM0->USART,
-        .rx_pin = GPIO_PIN(PA,9),
-        .tx_pin = GPIO_PIN(PA,10),
-        .mux    = GPIO_MUX_C,
-        .rx_pad = UART_PAD_RX_1,
-        .tx_pad = UART_PAD_TX_2,
+        .dev      = &SERCOM0->USART,
+        .rx_pin   = GPIO_PIN(PA,9),
+        .tx_pin   = GPIO_PIN(PA,10),
+        .mux      = GPIO_MUX_C,
+        .rx_pad   = UART_PAD_RX_1,
+        .tx_pad   = UART_PAD_TX_2,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     },
     {
-        .dev    = &SERCOM5->USART,
-        .rx_pin = GPIO_PIN(PB,31),
-        .tx_pin = GPIO_PIN(PB,30),
-        .mux    = GPIO_MUX_D,
-        .rx_pad = UART_PAD_RX_1,
-        .tx_pad = UART_PAD_TX_0_RTS_2_CTS_3,
+        .dev      = &SERCOM5->USART,
+        .rx_pin   = GPIO_PIN(PB,31),
+        .tx_pin   = GPIO_PIN(PB,30),
+        .mux      = GPIO_MUX_D,
+        .rx_pad   = UART_PAD_RX_1,
+        .tx_pad   = UART_PAD_TX_0_RTS_2_CTS_3,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     },
     {
-        .dev    = &SERCOM4->USART,
-        .rx_pin = GPIO_PIN(PB,13),
-        .tx_pin = GPIO_PIN(PA,14),
-        .mux    = GPIO_MUX_C,
-        .rx_pad = UART_PAD_RX_1,
-        .tx_pad = UART_PAD_TX_2,
+        .dev      = &SERCOM4->USART,
+        .rx_pin   = GPIO_PIN(PB,13),
+        .tx_pin   = GPIO_PIN(PA,14),
+        .mux      = GPIO_MUX_C,
+        .rx_pad   = UART_PAD_RX_1,
+        .tx_pad   = UART_PAD_TX_2,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     },
     {
-        .dev    = &SERCOM1->USART,
-        .rx_pin = GPIO_PIN(PA,17),
-        .tx_pin = GPIO_PIN(PA,18),
-        .mux    = GPIO_MUX_C,
-        .rx_pad = UART_PAD_RX_1,
-        .tx_pad = UART_PAD_TX_2,
+        .dev      = &SERCOM1->USART,
+        .rx_pin   = GPIO_PIN(PA,17),
+        .tx_pin   = GPIO_PIN(PA,18),
+        .mux      = GPIO_MUX_C,
+        .rx_pad   = UART_PAD_RX_1,
+        .tx_pad   = UART_PAD_TX_2,
+        .runstdby = 0,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0
     }
 };
 
diff --git a/cpu/sam0_common/periph/uart.c b/cpu/sam0_common/periph/uart.c
index fafe2cac9d..6e1c9fc219 100644
--- a/cpu/sam0_common/periph/uart.c
+++ b/cpu/sam0_common/periph/uart.c
@@ -51,44 +51,17 @@ static inline SercomUsart *_uart(uart_t dev)
 
 static uint64_t _long_division(uint64_t n, uint64_t d);
 
-/**
- * @brief   Get the sercom gclk id of the given UART device
- *
- * @param[in] dev       UART device identifier
- *
- * @return              sercom gclk id
- */
+static uint8_t sercom_gclk_id[] =
+        {
+            SERCOM0_GCLK_ID_CORE,
+            SERCOM1_GCLK_ID_CORE,
+            SERCOM2_GCLK_ID_CORE,
+            SERCOM3_GCLK_ID_CORE,
+            SERCOM4_GCLK_ID_CORE,
+            SERCOM5_GCLK_ID_CORE
+        };
 
-static int _get_sercom_gclk_id(SercomUsart *dev)
-{
-    int id;
 
-    switch(sercom_id(dev)) {
-        case 0:
-            id = SERCOM0_GCLK_ID_CORE;
-            break;
-        case 1:
-            id = SERCOM1_GCLK_ID_CORE;
-            break;
-        case 2:
-            id = SERCOM2_GCLK_ID_CORE;
-            break;
-        case 3:
-            id = SERCOM3_GCLK_ID_CORE;
-            break;
-        case 4:
-            id = SERCOM4_GCLK_ID_CORE;
-            break;
-        case 5:
-            id = SERCOM5_GCLK_ID_CORE;
-            break;
-        default:
-            id = -1;
-            DEBUG("[UART]: wrong SERCOM ID\n");
-            break;
-    }
-    return id;
-}
 #endif
 
 static int init_base(uart_t uart, uint32_t baudrate);
@@ -130,7 +103,7 @@ static int init_base(uart_t uart, uint32_t baudrate)
 
 #ifdef CPU_FAM_SAMD21
     /* calculate baudrate */
-    uint32_t  baud =  ((((uint32_t)CLOCK_CORECLOCK * 10) / baudrate) / 16);
+    uint32_t baud = ((((uint32_t)CLOCK_CORECLOCK * 10) / baudrate) / 16);
     /* enable sync and async clocks */
     uart_poweron(uart);
     /* reset the UART device */
@@ -210,11 +183,12 @@ void uart_poweron(uart_t uart)
     while (GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY) {}
 #elif CPU_FAM_SAML21
     /* Enable the peripheral channel */
-    GCLK->PCHCTRL[_get_sercom_gclk_id(dev)].reg |= GCLK_PCHCTRL_CHEN |
-                                                   GCLK_PCHCTRL_GEN(uart_config[uart].gclk_src);
+    GCLK->PCHCTRL[sercom_gclk_id[sercom_id(dev)]].reg |=
+            GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN(uart_config[uart].gclk_src);
 
-    while (!(GCLK->PCHCTRL[_get_sercom_gclk_id(dev)].reg & GCLK_PCHCTRL_CHEN)) {}
-    if(_get_sercom_gclk_id(dev) < 5) {
+    while (!(GCLK->PCHCTRL[sercom_gclk_id[sercom_id(dev)]].reg &
+           GCLK_PCHCTRL_CHEN)) {}
+    if(sercom_gclk_id[sercom_id(dev)] < 5) {
         MCLK->APBCMASK.reg |= MCLK_APBCMASK_SERCOM0 << sercom_id(dev);
     }
     else {
@@ -240,9 +214,9 @@ void uart_poweroff(uart_t uart)
     while (GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY) {}
 #elif CPU_FAM_SAML21
     /* Enable the peripheral channel */
-    GCLK->PCHCTRL[_get_sercom_gclk_id(dev)].reg &= ~GCLK_PCHCTRL_CHEN;
+    GCLK->PCHCTRL[sercom_gclk_id[sercom_id(dev)]].reg &= ~GCLK_PCHCTRL_CHEN;
 
-    if(_get_sercom_gclk_id(dev) < 5) {
+    if(sercom_gclk_id[sercom_id(dev)] < 5) {
         MCLK->APBCMASK.reg &= ~(MCLK_APBCMASK_SERCOM0 << sercom_id(dev));
     }
     else {
@@ -259,7 +233,8 @@ static inline void irq_handler(uint8_t uartnum)
 #ifdef CPU_FAM_SAMD21
     if (uart->INTFLAG.reg & SERCOM_USART_INTFLAG_RXC) {
         /* interrupt flag is cleared by reading the data register */
-        uart_ctx[uartnum].rx_cb(uart_ctx[uartnum].arg, (uint8_t)(uart->DATA.reg));
+        uart_ctx[uartnum].rx_cb(uart_ctx[uartnum].arg,
+                                (uint8_t)(uart->DATA.reg));
     }
     else if (uart->INTFLAG.reg & SERCOM_USART_INTFLAG_ERROR) {
         /* clear error flag */