diff --git a/boards/common/arduino-atmega/include/periph_conf.h b/boards/common/arduino-atmega/include/periph_conf.h
index 5a8a026a18..8f9bc59943 100644
--- a/boards/common/arduino-atmega/include/periph_conf.h
+++ b/boards/common/arduino-atmega/include/periph_conf.h
@@ -49,7 +49,8 @@ extern "C" {
  * @{
  */
 #ifdef CPU_ATMEGA328P
-#define TIMER_NUMOF         (2U)
+#define TIMER_NUMOF         (1U)
+#define TIMER_CHANNELS      (2)
 
 #define TIMER_0             MEGA_TIMER1
 #define TIMER_0_MASK        &TIMSK1
@@ -60,6 +61,7 @@ extern "C" {
 
 #ifdef CPU_ATMEGA2560
 #define TIMER_NUMOF         (2U)
+#define TIMER_CHANNELS      (3)
 
 #define TIMER_0             MEGA_TIMER1
 #define TIMER_0_MASK        &TIMSK1
diff --git a/boards/jiminy-mega256rfr2/include/periph_conf.h b/boards/jiminy-mega256rfr2/include/periph_conf.h
index 40c5600cd2..181aa2fd61 100644
--- a/boards/jiminy-mega256rfr2/include/periph_conf.h
+++ b/boards/jiminy-mega256rfr2/include/periph_conf.h
@@ -57,6 +57,7 @@ extern "C" {
  * @{
  */
 #define TIMER_NUMOF         (3U)
+#define TIMER_CHANNELS      (3)
 
 #define TIMER_0             MEGA_TIMER4
 #define TIMER_0_MASK        &TIMSK4
diff --git a/boards/mega-xplained/include/periph_conf.h b/boards/mega-xplained/include/periph_conf.h
index 6acb52069b..1be14db60c 100644
--- a/boards/mega-xplained/include/periph_conf.h
+++ b/boards/mega-xplained/include/periph_conf.h
@@ -51,6 +51,7 @@ extern "C" {
  * @{
  */
 #define TIMER_NUMOF         (2U)
+#define TIMER_CHANNELS      (2)
 
 #define TIMER_0             MEGA_TIMER1
 #define TIMER_0_MASK        &TIMSK1
diff --git a/boards/waspmote-pro/include/periph_conf.h b/boards/waspmote-pro/include/periph_conf.h
index d113f24425..01206b940e 100644
--- a/boards/waspmote-pro/include/periph_conf.h
+++ b/boards/waspmote-pro/include/periph_conf.h
@@ -44,6 +44,7 @@ extern "C" {
  * @{
  */
 #define TIMER_NUMOF         (2U)
+#define TIMER_CHANNELS      (3)
 
 #define TIMER_0             MEGA_TIMER1
 #define TIMER_0_MASK        &TIMSK1
diff --git a/cpu/atmega_common/periph/timer.c b/cpu/atmega_common/periph/timer.c
index cc420fd851..506271ee44 100644
--- a/cpu/atmega_common/periph/timer.c
+++ b/cpu/atmega_common/periph/timer.c
@@ -32,11 +32,6 @@
 #define ENABLE_DEBUG (0)
 #include "debug.h"
 
-/**
- * @brief   All timers have three channels
- */
-#define CHANNELS (3)
-
 /**
  * @brief   We have 5 possible prescaler values
  */
@@ -137,7 +132,7 @@ int timer_init(tim_t tim, unsigned long freq, timer_cb_t cb, void *arg)
 
 int timer_set_absolute(tim_t tim, int channel, unsigned int value)
 {
-    if (channel >= CHANNELS) {
+    if (channel >= TIMER_CHANNELS) {
         return -1;
     }
 
@@ -150,7 +145,7 @@ int timer_set_absolute(tim_t tim, int channel, unsigned int value)
 
 int timer_clear(tim_t tim, int channel)
 {
-    if (channel >= CHANNELS) {
+    if (channel >= TIMER_CHANNELS) {
         return -1;
     }