diff --git a/boards/common/arduino-due/include/periph_conf.h b/boards/common/arduino-due/include/periph_conf.h
index 3861d24e86..20be9b26e7 100644
--- a/boards/common/arduino-due/include/periph_conf.h
+++ b/boards/common/arduino-due/include/periph_conf.h
@@ -76,7 +76,9 @@ static const timer_conf_t timer_config[] = {
  * @name    RTT configuration
  * @{
  */
+#ifndef RTT_FREQUENCY
 #define RTT_FREQUENCY       (1U)        /* 1Hz */
+#endif
 /** @} */
 
 /**
diff --git a/cpu/sam3/include/periph_cpu.h b/cpu/sam3/include/periph_cpu.h
index 7f28e5ef56..7872489a02 100644
--- a/cpu/sam3/include/periph_cpu.h
+++ b/cpu/sam3/include/periph_cpu.h
@@ -76,9 +76,14 @@ typedef uint32_t gpio_t;
 #define TIMER_CHANNEL_NUMOF (1)
 
 /**
- * @brief   The RTT width is fixed to 32-bit
+ * @name    RTT configuration
+ * @{
  */
 #define RTT_MAX_VALUE       (0xffffffff)
+#define RTT_CLOCK_FREQUENCY (CHIP_FREQ_XTAL_32K)          /* in Hz */
+#define RTT_MIN_FREQUENCY   (1) /* in Hz */
+#define RTT_MAX_FREQUENCY   (RTT_CLOCK_FREQUENCY)         /* in Hz */
+/** @} */
 
 /**
  * @brief   Generate GPIO mode bitfields