diff --git a/boards/common/slwstk6000b/include/periph_conf.h b/boards/common/slwstk6000b/include/periph_conf.h
index e30471fd76..7f74dd90b9 100644
--- a/boards/common/slwstk6000b/include/periph_conf.h
+++ b/boards/common/slwstk6000b/include/periph_conf.h
@@ -147,7 +147,8 @@ static const timer_conf_t timer_config[] = {
             .dev = TIMER1,
             .cmu = cmuClock_TIMER1
         },
-        .irq = TIMER1_IRQn
+        .irq = TIMER1_IRQn,
+        .channel_numof = 3
     }
 };
 
diff --git a/boards/ikea-tradfri/include/board.h b/boards/ikea-tradfri/include/board.h
index 108f827236..27af510a54 100644
--- a/boards/ikea-tradfri/include/board.h
+++ b/boards/ikea-tradfri/include/board.h
@@ -34,12 +34,15 @@ extern "C" {
  * The timer runs at 250 kHz to increase accuracy or 32768 Hz for LETIMER.
  * @{
  */
-#ifdef EFM32_USE_LETIMER
+#if IS_ACTIVE(CONFIG_EFM32_XTIMER_USE_LETIMER)
+#define XTIMER_DEV          (TIMER_DEV(1))
 #define XTIMER_HZ           (32768UL)
 #else
+#define XTIMER_DEV          (TIMER_DEV(0))
 #define XTIMER_HZ           (250000UL)
 #endif
 #define XTIMER_WIDTH        (16)
+#define XTIMER_CHAN (0)
 /** @} */
 
 /**
diff --git a/boards/ikea-tradfri/include/periph_conf.h b/boards/ikea-tradfri/include/periph_conf.h
index 77e72a3f9c..98122ea566 100644
--- a/boards/ikea-tradfri/include/periph_conf.h
+++ b/boards/ikea-tradfri/include/periph_conf.h
@@ -85,19 +85,6 @@ static const spi_dev_t spi_config[] = {
  * or two regular timers in cascade mode.
  * @{
  */
-#if EFM32_USE_LETIMER
-static const timer_conf_t timer_config[] = {
-    {
-        .timer = {
-            .dev = LETIMER0,
-            .cmu = cmuClock_LETIMER0
-        },
-        .irq = LETIMER0_IRQn
-    }
-};
-#define TIMER_0_ISR         isr_letimer0
-
-#else
 static const timer_conf_t timer_config[] = {
     {
         .prescaler = {
@@ -108,12 +95,25 @@ static const timer_conf_t timer_config[] = {
             .dev = TIMER1,
             .cmu = cmuClock_TIMER1
         },
-        .irq = TIMER1_IRQn
-    }
+        .irq = TIMER1_IRQn,
+        .channel_numof = 3
+    },
+    {
+        .prescaler = {
+            .dev = NULL,
+            .cmu = cmuClock_LETIMER0
+        },
+        .timer = {
+            .dev = LETIMER0,
+            .cmu = cmuClock_LETIMER0
+        },
+        .irq = LETIMER0_IRQn,
+        .channel_numof = 2
+    },
 };
-#define TIMER_0_ISR         isr_timer1
 
-#endif /* EFM32_USE_LETIMER */
+#define TIMER_0_ISR         isr_timer1
+#define TIMER_1_ISR         isr_letimer0
 
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
 /** @} */
diff --git a/boards/slstk3401a/include/board.h b/boards/slstk3401a/include/board.h
index 40a9157694..6894b13576 100644
--- a/boards/slstk3401a/include/board.h
+++ b/boards/slstk3401a/include/board.h
@@ -35,12 +35,15 @@ extern "C" {
  * The timer runs at 250 KHz to increase accuracy or 32768 Hz for LETIMER.
  * @{
  */
-#ifdef EFM32_USE_LETIMER
+#if IS_ACTIVE(CONFIG_EFM32_XTIMER_USE_LETIMER)
+#define XTIMER_DEV          (TIMER_DEV(1))
 #define XTIMER_HZ           (32768UL)
 #else
+#define XTIMER_DEV          (TIMER_DEV(0))
 #define XTIMER_HZ           (250000UL)
 #endif
 #define XTIMER_WIDTH        (16)
+#define XTIMER_CHAN (0)
 /** @} */
 
 /**
diff --git a/boards/slstk3401a/include/periph_conf.h b/boards/slstk3401a/include/periph_conf.h
index 2a3ad6ba5f..dc034e4f16 100644
--- a/boards/slstk3401a/include/periph_conf.h
+++ b/boards/slstk3401a/include/periph_conf.h
@@ -145,19 +145,6 @@ static const spi_dev_t spi_config[] = {
  * or two regular timers in cascade mode.
  * @{
  */
-#if EFM32_USE_LETIMER
-static const timer_conf_t timer_config[] = {
-    {
-        .timer = {
-            .dev = LETIMER0,
-            .cmu = cmuClock_LETIMER0
-        },
-        .irq = LETIMER0_IRQn
-    }
-};
-#define TIMER_0_ISR         isr_letimer0
-
-#else
 static const timer_conf_t timer_config[] = {
     {
         .prescaler = {
@@ -168,12 +155,25 @@ static const timer_conf_t timer_config[] = {
             .dev = TIMER1,
             .cmu = cmuClock_TIMER1
         },
-        .irq = TIMER1_IRQn
-    }
+        .irq = TIMER1_IRQn,
+        .channel_numof = 3
+    },
+    {
+        .prescaler = {
+            .dev = NULL,
+            .cmu = cmuClock_LETIMER0
+        },
+        .timer = {
+            .dev = LETIMER0,
+            .cmu = cmuClock_LETIMER0
+        },
+        .irq = LETIMER0_IRQn,
+        .channel_numof = 2
+    },
 };
-#define TIMER_0_ISR         isr_timer1
 
-#endif /* EFM32_USE_LETIMER */
+#define TIMER_0_ISR         isr_timer1
+#define TIMER_1_ISR         isr_letimer0
 
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
 /** @} */
diff --git a/boards/slstk3402a/include/board.h b/boards/slstk3402a/include/board.h
index b4149c1f00..3b3c6e12dd 100644
--- a/boards/slstk3402a/include/board.h
+++ b/boards/slstk3402a/include/board.h
@@ -33,13 +33,16 @@ extern "C" {
  * @name    Xtimer configuration
  * @{
  */
-#ifdef EFM32_USE_LETIMER
+#if IS_ACTIVE(CONFIG_EFM32_XTIMER_USE_LETIMER)
+#define XTIMER_DEV          (TIMER_DEV(1))
 #define XTIMER_HZ           (32768UL)
 #define XTIMER_WIDTH        (16)
 #else
+#define XTIMER_DEV          (TIMER_DEV(0))
 #define XTIMER_HZ           (1000000UL)
 #define XTIMER_WIDTH        (32)
 #endif
+#define XTIMER_CHAN (0)
 /** @} */
 
 /**
diff --git a/boards/slstk3402a/include/periph_conf.h b/boards/slstk3402a/include/periph_conf.h
index dfefe0bd5c..866be39ede 100644
--- a/boards/slstk3402a/include/periph_conf.h
+++ b/boards/slstk3402a/include/periph_conf.h
@@ -136,19 +136,6 @@ static const spi_dev_t spi_config[] = {
  * or two regular timers in cascade mode.
  * @{
  */
-#if EFM32_USE_LETIMER
-static const timer_conf_t timer_config[] = {
-    {
-        .timer = {
-            .dev = LETIMER0,
-            .cmu = cmuClock_LETIMER0
-        },
-        .irq = LETIMER0_IRQn
-    }
-};
-#define TIMER_0_ISR         isr_letimer0
-
-#else
 static const timer_conf_t timer_config[] = {
     {
         .prescaler = {
@@ -159,12 +146,25 @@ static const timer_conf_t timer_config[] = {
             .dev = WTIMER1,
             .cmu = cmuClock_WTIMER1
         },
-        .irq = WTIMER1_IRQn
-    }
+        .irq = WTIMER1_IRQn,
+        .channel_numof = 3
+    },
+    {
+        .prescaler = {
+            .dev = NULL,
+            .cmu = cmuClock_LETIMER0
+        },
+        .timer = {
+            .dev = LETIMER0,
+            .cmu = cmuClock_LETIMER0
+        },
+        .irq = LETIMER0_IRQn,
+        .channel_numof = 2
+    },
 };
-#define TIMER_0_ISR         isr_wtimer1
 
-#endif /* EFM32_USE_LETIMER */
+#define TIMER_0_ISR         isr_wtimer1
+#define TIMER_1_ISR         isr_letimer0
 
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
 /** @} */
diff --git a/boards/sltb001a/include/board.h b/boards/sltb001a/include/board.h
index 1291ca66e9..aced867dc1 100644
--- a/boards/sltb001a/include/board.h
+++ b/boards/sltb001a/include/board.h
@@ -35,13 +35,16 @@ extern "C" {
  * The timer runs at 250 KHz to increase accuracy or 32768 Hz for LETIMER.
  * @{
  */
-#ifdef EFM32_USE_LETIMER
+#if IS_ACTIVE(CONFIG_EFM32_XTIMER_USE_LETIMER)
+#define XTIMER_DEV          (TIMER_DEV(1))
 #define XTIMER_HZ           (32768UL)
 #define XTIMER_WIDTH        (16)
 #else
+#define XTIMER_DEV          (TIMER_DEV(0))
 #define XTIMER_HZ           (250000UL)
 #define XTIMER_WIDTH        (16)
 #endif
+#define XTIMER_CHAN (0)
 /** @} */
 
 /**
diff --git a/boards/sltb001a/include/periph_conf.h b/boards/sltb001a/include/periph_conf.h
index ddc13e9645..7662a53bff 100644
--- a/boards/sltb001a/include/periph_conf.h
+++ b/boards/sltb001a/include/periph_conf.h
@@ -145,19 +145,6 @@ static const spi_dev_t spi_config[] = {
  * or two regular timers in cascade mode.
  * @{
  */
-#if EFM32_USE_LETIMER
-static const timer_conf_t timer_config[] = {
-    {
-        .timer = {
-            .dev = LETIMER0,
-            .cmu = cmuClock_LETIMER0
-        },
-        .irq = LETIMER0_IRQn
-    }
-};
-#define TIMER_0_ISR         isr_letimer0
-
-#else
 static const timer_conf_t timer_config[] = {
     {
         .prescaler = {
@@ -168,12 +155,25 @@ static const timer_conf_t timer_config[] = {
             .dev = TIMER1,
             .cmu = cmuClock_TIMER1
         },
-        .irq = TIMER1_IRQn
-    }
+        .irq = TIMER1_IRQn,
+        .channel_numof = 3
+    },
+    {
+        .prescaler = {
+            .dev = NULL,
+            .cmu = cmuClock_LETIMER0
+        },
+        .timer = {
+            .dev = LETIMER0,
+            .cmu = cmuClock_LETIMER0
+        },
+        .irq = LETIMER0_IRQn,
+        .channel_numof = 2
+    },
 };
-#define TIMER_0_ISR         isr_timer1
 
-#endif /* EFM32_USE_LETIMER */
+#define TIMER_0_ISR         isr_timer1
+#define TIMER_1_ISR         isr_letimer0
 
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
 /** @} */
diff --git a/boards/stk3600/include/board.h b/boards/stk3600/include/board.h
index 52e0869e08..60822e884b 100644
--- a/boards/stk3600/include/board.h
+++ b/boards/stk3600/include/board.h
@@ -35,13 +35,16 @@ extern "C" {
  * The timer runs at 250 KHz to increase accuracy or 32768 Hz for LETIMER.
  * @{
  */
-#ifdef EFM32_USE_LETIMER
+#if IS_ACTIVE(CONFIG_EFM32_XTIMER_USE_LETIMER)
+#define XTIMER_DEV          (TIMER_DEV(1))
 #define XTIMER_HZ           (32768UL)
 #define XTIMER_WIDTH        (16)
 #else
+#define XTIMER_DEV          (TIMER_DEV(0))
 #define XTIMER_HZ           (250000UL)
 #define XTIMER_WIDTH        (16)
 #endif
+#define XTIMER_CHAN (0)
 /** @} */
 
 /**
diff --git a/boards/stk3600/include/periph_conf.h b/boards/stk3600/include/periph_conf.h
index bbef6a9327..42a6493cd8 100644
--- a/boards/stk3600/include/periph_conf.h
+++ b/boards/stk3600/include/periph_conf.h
@@ -199,19 +199,6 @@ static const spi_dev_t spi_config[] = {
  * or two regular timers in cascade mode.
  * @{
  */
-#if EFM32_USE_LETIMER
-static const timer_conf_t timer_config[] = {
-    {
-        .timer = {
-            .dev = LETIMER0,
-            .cmu = cmuClock_LETIMER0
-        },
-        .irq = LETIMER0_IRQn
-    }
-};
-#define TIMER_0_ISR         isr_letimer0
-
-#else
 static const timer_conf_t timer_config[] = {
     {
         .prescaler = {
@@ -222,12 +209,25 @@ static const timer_conf_t timer_config[] = {
             .dev = TIMER1,
             .cmu = cmuClock_TIMER1
         },
-        .irq = TIMER1_IRQn
-    }
+        .irq = TIMER1_IRQn,
+        .channel_numof = 3
+    },
+    {
+        .prescaler = {
+            .dev = NULL,
+            .cmu = cmuClock_LETIMER0
+        },
+        .timer = {
+            .dev = LETIMER0,
+            .cmu = cmuClock_LETIMER0
+        },
+        .irq = LETIMER0_IRQn,
+        .channel_numof = 2
+    },
 };
-#define TIMER_0_ISR         isr_timer1
 
-#endif /* EFM32_USE_LETIMER */
+#define TIMER_0_ISR         isr_timer1
+#define TIMER_1_ISR         isr_letimer0
 
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
 /** @} */
diff --git a/boards/stk3700/include/board.h b/boards/stk3700/include/board.h
index 973c6b2399..58fc3f02cd 100644
--- a/boards/stk3700/include/board.h
+++ b/boards/stk3700/include/board.h
@@ -35,13 +35,16 @@ extern "C" {
  * The timer runs at 250 KHz to increase accuracy or 32768 Hz for LETIMER.
  * @{
  */
-#ifdef EFM32_USE_LETIMER
+#if IS_ACTIVE(CONFIG_EFM32_XTIMER_USE_LETIMER)
+#define XTIMER_DEV          (TIMER_DEV(1))
 #define XTIMER_HZ           (32768UL)
 #define XTIMER_WIDTH        (16)
 #else
+#define XTIMER_DEV          (TIMER_DEV(0))
 #define XTIMER_HZ           (250000UL)
 #define XTIMER_WIDTH        (16)
 #endif
+#define XTIMER_CHAN (0)
 /** @} */
 
 /**
diff --git a/boards/stk3700/include/periph_conf.h b/boards/stk3700/include/periph_conf.h
index 01829e99a9..e63f566fa0 100644
--- a/boards/stk3700/include/periph_conf.h
+++ b/boards/stk3700/include/periph_conf.h
@@ -199,19 +199,6 @@ static const spi_dev_t spi_config[] = {
  * or two regular timers in cascade mode.
  * @{
  */
-#if EFM32_USE_LETIMER
-static const timer_conf_t timer_config[] = {
-    {
-        .timer = {
-            .dev = LETIMER0,
-            .cmu = cmuClock_LETIMER0
-        },
-        .irq = LETIMER0_IRQn
-    }
-};
-#define TIMER_0_ISR         isr_letimer0
-
-#else
 static const timer_conf_t timer_config[] = {
     {
         .prescaler = {
@@ -222,12 +209,25 @@ static const timer_conf_t timer_config[] = {
             .dev = TIMER1,
             .cmu = cmuClock_TIMER1
         },
-        .irq = TIMER1_IRQn
-    }
+        .irq = TIMER1_IRQn,
+        .channel_numof = 3
+    },
+    {
+        .prescaler = {
+            .dev = NULL,
+            .cmu = cmuClock_LETIMER0
+        },
+        .timer = {
+            .dev = LETIMER0,
+            .cmu = cmuClock_LETIMER0
+        },
+        .irq = LETIMER0_IRQn,
+        .channel_numof = 2
+    },
 };
-#define TIMER_0_ISR         isr_timer1
 
-#endif /* EFM32_USE_LETIMER */
+#define TIMER_0_ISR         isr_timer1
+#define TIMER_1_ISR         isr_letimer0
 
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
 /** @} */
diff --git a/cpu/efm32/include/periph_cpu.h b/cpu/efm32/include/periph_cpu.h
index 6ef3507a33..963a87f7dc 100644
--- a/cpu/efm32/include/periph_cpu.h
+++ b/cpu/efm32/include/periph_cpu.h
@@ -20,6 +20,7 @@
 #ifndef PERIPH_CPU_H
 #define PERIPH_CPU_H
 
+#include "kernel_defines.h"
 #include "mutex.h"
 
 #include "cpu_conf.h"
@@ -356,28 +357,18 @@ typedef struct {
     timer_dev_t prescaler;  /**< the lower neighboring timer (not initialized for LETIMER) */
     timer_dev_t timer;      /**< the higher numbered timer */
     IRQn_Type irq;          /**< number of the higher timer IRQ channel */
+    uint8_t channel_numof;       /**< number of channels per timer */
 } timer_conf_t;
 /** @} */
 
 
 /**
- * @brief   The implementation can use one LETIMER or two regular timers cascaded
+ * @brief   Use LETIMER as the base timer for XTIMER
  */
-#ifndef EFM32_USE_LETIMER
-#define EFM32_USE_LETIMER   0
+#ifndef CONFIG_EFM32_XTIMER_USE_LETIMER
+#define CONFIG_EFM32_XTIMER_USE_LETIMER   0
 #endif
 
-#ifdef EFM32_USE_LETIMER
-/**
- * @brief   This timer implementation has two available channels
- */
-#define TIMER_CHANNEL_NUMOF     (2)
-#else
-/**
- * @brief   This timer implementation has three available channels
- */
-#define TIMER_CHANNEL_NUMOF     (3)
-#endif
 
 /**
  * @brief   UART device configuration.
diff --git a/cpu/efm32/periph/timer.c b/cpu/efm32/periph/timer.c
index ff291340f9..08fd27f17b 100644
--- a/cpu/efm32/periph/timer.c
+++ b/cpu/efm32/periph/timer.c
@@ -111,8 +111,7 @@ static void _timer_init(tim_t dev, unsigned long freq)
     TIMER_Init_TypeDef init_pre = TIMER_INIT_DEFAULT;
     TIMER_Init_TypeDef init_tim = TIMER_INIT_DEFAULT;
 
-    /* leave the prescaler enabled and toggle only the primary timer */
-    init_pre.enable = true;
+    init_pre.enable = false;
     init_pre.prescale = timerPrescale1;
     init_tim.enable = false;
     init_tim.clkSel = timerClkSelCascade;
@@ -166,7 +165,7 @@ int timer_set_absolute(tim_t dev, int channel, unsigned int value)
     if (!_is_letimer(dev)) {
         TIMER_TypeDef *tim = timer_config[dev].timer.dev;
 
-        if (channel < 0 || channel >= TIMER_CHANNEL_NUMOF) {
+        if (channel < 0 || channel >= timer_config[dev].channel_numof) {
             return -1;
         }
 
@@ -256,6 +255,7 @@ void timer_stop(tim_t dev)
             pm_unblock(EFM32_TIMER_PM_BLOCKER);
         }
         TIMER_Enable(timer_config[dev].timer.dev, false);
+        TIMER_Enable(timer_config[dev].prescaler.dev, false);
     }
 }
 
@@ -274,18 +274,16 @@ void timer_start(tim_t dev)
             pm_block(EFM32_TIMER_PM_BLOCKER);
         }
         TIMER_Enable(timer_config[dev].timer.dev, true);
+        TIMER_Enable(timer_config[dev].prescaler.dev, true);
     }
 }
 
-#ifdef TIMER_0_ISR
-void TIMER_0_ISR(void)
+static void _timer_isr(tim_t dev)
 {
-    tim_t dev = 0;
-
     if (_is_letimer(dev)) {
         LETIMER_TypeDef *tim = timer_config[dev].timer.dev;
 
-        for (int i = 0; i < TIMER_CHANNEL_NUMOF; i++) {
+        for (int i = 0; i < timer_config[dev].channel_numof; i++) {
             if (tim->IF & (LETIMER_IF_COMP0 << i))
             {
                 LETIMER_IntDisable(tim, LETIMER_IEN_COMP0 << i);
@@ -297,7 +295,7 @@ void TIMER_0_ISR(void)
     else {
         TIMER_TypeDef *tim = timer_config[dev].timer.dev;
 
-        for (int i = 0; i < TIMER_CHANNEL_NUMOF; i++) {
+        for (int i = 0; i < timer_config[dev].channel_numof; i++) {
             if (tim->IF & (TIMER_IF_CC0 << i)) {
                 tim->CC[i].CTRL = _TIMER_CC_CTRL_MODE_OFF;
                 tim->IFC = (TIMER_IFC_CC0 << i);
@@ -307,4 +305,17 @@ void TIMER_0_ISR(void)
     }
     cortexm_isr_end();
 }
+
+#ifdef TIMER_0_ISR
+void TIMER_0_ISR(void)
+{
+    _timer_isr(0);
+}
 #endif /* TIMER_0_ISR */
+
+#ifdef TIMER_1_ISR
+void TIMER_1_ISR(void)
+{
+    _timer_isr(1);
+}
+#endif /* TIMER_1_ISR */
diff --git a/tests/periph_timer/Makefile b/tests/periph_timer/Makefile
index d86e686a82..94a4ea9b08 100644
--- a/tests/periph_timer/Makefile
+++ b/tests/periph_timer/Makefile
@@ -19,6 +19,11 @@ BOARDS_TIMER_32kHz := \
     openlabs-kw41z-mini \
     frdm-k64f \
     frdm-k22f \
+    slstk3401a \
+    slstk3402a \
+    sltb001a \
+    stk3600 \
+    stk3700 \
     #
 
 BOARDS_TIMER_CLOCK_CORECLOCK := \
diff --git a/tests/periph_timer_periodic/main.c b/tests/periph_timer_periodic/main.c
index 09fc0c2580..640b057a80 100644
--- a/tests/periph_timer_periodic/main.c
+++ b/tests/periph_timer_periodic/main.c
@@ -37,11 +37,16 @@
  * as xtimer is not used in this test, we can use it and the fact that every board
  * provides a configuration for it.
  */
-#define TIMER_CYCL  XTIMER_DEV
-#define CYCLE_MS    25UL
-#define CYCLES_MAX   10
+#define TIMER_CYCL      (XTIMER_DEV)
+#define CYCLE_MS        (25UL)
+#define CYCLES_MAX      (10)
+#ifdef TIMER_CHANNEL_NUMOF
+#define MAX_CHANNELS    (TIMER_CHANNEL_NUMOF)
+#else
+#define MAX_CHANNELS    (10)
+#endif
 
-static unsigned count[TIMER_CHANNEL_NUMOF];
+static unsigned count[MAX_CHANNELS];
 
 static void cb(void *arg, int chan)
 {
@@ -85,7 +90,13 @@ int main(void)
 
     /* Only the first channel should trigger and reset the counter */
     /* If subsequent channels trigger this is an error. */
-    timer_set_periodic(TIMER_CYCL, 1, 2 * steps, TIM_FLAG_RESET_ON_SET);
+    unsigned channel_numof = 1;
+    for(unsigned i = 1; i < MAX_CHANNELS; i++) {
+        if(!timer_set_periodic(TIMER_CYCL, i, (1 + i) * steps, TIM_FLAG_RESET_ON_SET)) {
+            channel_numof = i;
+            break;
+        }
+    }
     timer_set_periodic(TIMER_CYCL, 0, steps, TIM_FLAG_RESET_ON_MATCH);
 
     mutex_lock(&lock);
@@ -93,7 +104,7 @@ int main(void)
     puts("\nCycles:");
 
     bool succeeded = true;
-    for (unsigned i = 0; i < TIMER_CHANNEL_NUMOF; ++i) {
+    for (unsigned i = 0; i < channel_numof; ++i) {
         printf("channel %u = %02u\t[%s]\n", i, count[i], _print_ok(i, &succeeded));
     }