diff --git a/boards/common/arduino-mkr/include/periph_conf_common.h b/boards/common/arduino-mkr/include/periph_conf_common.h
index c5f22f62d9..97cdc606d8 100644
--- a/boards/common/arduino-mkr/include/periph_conf_common.h
+++ b/boards/common/arduino-mkr/include/periph_conf_common.h
@@ -189,24 +189,13 @@ static const i2c_conf_t i2c_config[] = {
 #define I2C_NUMOF           ARRAY_SIZE(i2c_config)
 /** @} */
 
-/**
- * @name RTC configuration
- * @{
- */
-#define RTC_DEV             RTC->MODE2
-/** @} */
-
 /**
  * @name RTT configuration
  * @{
  */
-#define RTT_DEV             RTC->MODE0
-#define RTT_IRQ             RTC_IRQn
-#define RTT_IRQ_PRIO        10
-#define RTT_ISR             isr_rtc
-#define RTT_MAX_VALUE       (0xffffffff)
+#ifndef RTT_FREQUENCY
 #define RTT_FREQUENCY       (32768U)    /* in Hz. For changes see `rtt.c` */
-#define RTT_RUNSTDBY        (1)         /* Keep RTT running in sleep states */
+#endif
 /** @} */
 
 /**
diff --git a/boards/common/arduino-zero/include/periph_conf.h b/boards/common/arduino-zero/include/periph_conf.h
index 1114acadba..1f4610bfb2 100644
--- a/boards/common/arduino-zero/include/periph_conf.h
+++ b/boards/common/arduino-zero/include/periph_conf.h
@@ -267,24 +267,13 @@ static const i2c_conf_t i2c_config[] = {
 #define I2C_NUMOF           ARRAY_SIZE(i2c_config)
 /** @} */
 
-/**
- * @name RTC configuration
- * @{
- */
-#define RTC_DEV             RTC->MODE2
-/** @} */
-
 /**
  * @name RTT configuration
  * @{
  */
-#define RTT_DEV             RTC->MODE0
-#define RTT_IRQ             RTC_IRQn
-#define RTT_IRQ_PRIO        10
-#define RTT_ISR             isr_rtc
-#define RTT_MAX_VALUE       (0xffffffff)
+#ifndef RTT_FREQUENCY
 #define RTT_FREQUENCY       (32768U)    /* in Hz. For changes see `rtt.c` */
-#define RTT_RUNSTDBY        (1)         /* Keep RTT running in sleep states */
+#endif
 /** @} */
 
 /**
diff --git a/boards/common/sodaq/include/cfg_rtt_default.h b/boards/common/sodaq/include/cfg_rtt_default.h
index a73c1a135c..0a6230a7bd 100644
--- a/boards/common/sodaq/include/cfg_rtt_default.h
+++ b/boards/common/sodaq/include/cfg_rtt_default.h
@@ -32,13 +32,9 @@ extern "C" {
  * @name RTT configuration
  * @{
  */
-#define RTT_DEV             RTC->MODE0
-#define RTT_IRQ             RTC_IRQn
-#define RTT_IRQ_PRIO        10
-#define RTT_ISR             isr_rtc
-#define RTT_MAX_VALUE       (0xffffffff)
+#ifndef RTT_FREQUENCY
 #define RTT_FREQUENCY       (32768U)    /* in Hz. For changes see `rtt.c` */
-#define RTT_RUNSTDBY        (1)         /* Keep RTT running in sleep states */
+#endif
 /** @} */
 
 #ifdef __cplusplus
diff --git a/boards/feather-m0/include/periph_conf.h b/boards/feather-m0/include/periph_conf.h
index ce3f6c37b8..9b4dec9af2 100644
--- a/boards/feather-m0/include/periph_conf.h
+++ b/boards/feather-m0/include/periph_conf.h
@@ -248,23 +248,12 @@ static const i2c_conf_t i2c_config[] = {
 /** @} */
 
 /**
- * @name    RTC configuration
+ * @name RTT configuration
  * @{
  */
-#define RTC_DEV             RTC->MODE2
-/** @} */
-
-/**
- * @name    RTT configuration
- * @{
- */
-#define RTT_DEV             RTC->MODE0
-#define RTT_IRQ             RTC_IRQn
-#define RTT_IRQ_PRIO        10
-#define RTT_ISR             isr_rtc
-#define RTT_MAX_VALUE       (0xffffffff)
+#ifndef RTT_FREQUENCY
 #define RTT_FREQUENCY       (32768U)    /* in Hz. For changes see `rtt.c` */
-#define RTT_RUNSTDBY        (1)         /* Keep RTT running in sleep states */
+#endif
 /** @} */
 
 /**
diff --git a/boards/hamilton/include/periph_conf.h b/boards/hamilton/include/periph_conf.h
index 7cfda8f8db..e8b169c14a 100644
--- a/boards/hamilton/include/periph_conf.h
+++ b/boards/hamilton/include/periph_conf.h
@@ -88,23 +88,12 @@ extern "C" {
 /** @} */
 
 /**
- * @name    RTC configuration
+ * @name RTT configuration
  * @{
  */
-#define RTC_DEV             RTC->MODE2
-/** @} */
-
-/**
- * @name    RTT configuration
- * @{
- */
-#define RTT_DEV             RTC->MODE0
-#define RTT_IRQ             RTC_IRQn
-#define RTT_IRQ_PRIO        10
-#define RTT_ISR             isr_rtc
-#define RTT_MAX_VALUE       (0xffffffff)
+#ifndef RTT_FREQUENCY
 #define RTT_FREQUENCY       (32768U)    /* in Hz. For changes see `rtt.c` */
-#define RTT_RUNSTDBY        (1)         /* Keep RTT running in sleep states */
+#endif
 /** @} */
 
 /**
diff --git a/boards/samd21-xpro/include/periph_conf.h b/boards/samd21-xpro/include/periph_conf.h
index 7d451ea421..a6613925ee 100644
--- a/boards/samd21-xpro/include/periph_conf.h
+++ b/boards/samd21-xpro/include/periph_conf.h
@@ -316,24 +316,13 @@ static const i2c_conf_t i2c_config[] = {
 #define I2C_NUMOF          ARRAY_SIZE(i2c_config)
 /** @} */
 
-/**
- * @name RTC configuration
- * @{
- */
-#define RTC_DEV             RTC->MODE2
-/** @} */
-
 /**
  * @name RTT configuration
  * @{
  */
-#define RTT_DEV             RTC->MODE0
-#define RTT_IRQ             RTC_IRQn
-#define RTT_IRQ_PRIO        10
-#define RTT_ISR             isr_rtc
-#define RTT_MAX_VALUE       (0xffffffff)
+#ifndef RTT_FREQUENCY
 #define RTT_FREQUENCY       (32768U)    /* in Hz. For changes see `rtt.c` */
-#define RTT_RUNSTDBY        (1)         /* Keep RTT running in sleep states */
+#endif
 /** @} */
 
 /**
diff --git a/boards/samr21-xpro/include/periph_conf.h b/boards/samr21-xpro/include/periph_conf.h
index 2624d3388f..2c9ab96b4f 100644
--- a/boards/samr21-xpro/include/periph_conf.h
+++ b/boards/samr21-xpro/include/periph_conf.h
@@ -283,24 +283,13 @@ static const i2c_conf_t i2c_config[] = {
 /** @} */
 
 /**
- * @name    RTC configuration
+ * @name RTT configuration
  * @{
  */
-#define RTC_DEV             RTC->MODE2
-/** @} */
-
-/**
- * @name    RTT configuration
- * @{
- */
-#define RTT_DEV             RTC->MODE0
-#define RTT_IRQ             RTC_IRQn
-#define RTT_IRQ_PRIO        10
-#define RTT_ISR             isr_rtc
-#define RTT_MAX_VALUE       (0xffffffff)
-#define RTT_MIN_OFFSET      (10U)
+#ifndef RTT_FREQUENCY
 #define RTT_FREQUENCY       (32768U)    /* in Hz. For changes see `rtt.c` */
-#define RTT_RUNSTDBY        (1)         /* Keep RTT running in sleep states */
+#endif
+#define RTT_MIN_OFFSET      (10U)
 /** @} */
 
 /**
diff --git a/boards/serpente/include/periph_conf.h b/boards/serpente/include/periph_conf.h
index 0fc26888d4..832668c558 100644
--- a/boards/serpente/include/periph_conf.h
+++ b/boards/serpente/include/periph_conf.h
@@ -212,8 +212,9 @@ static const i2c_conf_t i2c_config[] = {
  * @name    RTT configuration
  * @{
  */
-#define RTT_MAX_VALUE       (0xffffffff)
+#ifndef RTT_FREQUENCY
 #define RTT_FREQUENCY       (32768U)    /* in Hz. For changes see `rtt.c` */
+#endif
 /** @} */
 
 /**
diff --git a/cpu/samd21/include/periph_cpu.h b/cpu/samd21/include/periph_cpu.h
index aed4f91fab..1018355ed1 100644
--- a/cpu/samd21/include/periph_cpu.h
+++ b/cpu/samd21/include/periph_cpu.h
@@ -127,6 +127,18 @@ typedef enum {
  */
 #define DAC_NUMOF           (1)
 
+/**
+ * @name    Real time counter configuration
+ * @{
+ */
+#define RTT_RUNSTDBY        (1)         /* Keep RTT running in sleep states */
+
+#define RTT_MAX_VALUE       (0xffffffff)
+#define RTT_CLOCK_FREQUENCY (32768U)                      /* in Hz */
+#define RTT_MIN_FREQUENCY   (RTT_CLOCK_FREQUENCY / 1024U) /* in Hz */
+#define RTT_MAX_FREQUENCY   (RTT_CLOCK_FREQUENCY)         /* in Hz */
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif