diff --git a/cpu/msp430-common/include/cpu.h b/cpu/msp430-common/include/cpu.h
index 366966becf..0843f81907 100644
--- a/cpu/msp430-common/include/cpu.h
+++ b/cpu/msp430-common/include/cpu.h
@@ -30,8 +30,9 @@ License. See the file LICENSE in the top level directory for more details.
 
 #define WORDSIZE 16
 
-/* not used(?) */
-#define F_CPU 10000000
+/* CPU speed */
+#define F_CPU               (2457600ul)
+#define F_RC_OSCILLATOR		(32768)	///< Frequency of internal RC oscillator
 
 extern volatile int __inISR;
 extern char __isr_stack[MSP430_ISR_STACK_SIZE];
diff --git a/cpu/msp430-common/include/hwtimer_cpu.h b/cpu/msp430-common/include/hwtimer_cpu.h
index 1eea5df491..735b4dd1a0 100644
--- a/cpu/msp430-common/include/hwtimer_cpu.h
+++ b/cpu/msp430-common/include/hwtimer_cpu.h
@@ -36,7 +36,7 @@ License. See the file LICENSE in the top level directory for more details.
 #define ARCH_MAXTIMERS 0
 #endif
 
-#define HWTIMER_SPEED 32768
+#define HWTIMER_SPEED  (F_RC_OSCILLATOR)
 #define HWTIMER_MAXTICKS (0xFFFFFFFF)
 
 #endif // __HWTIMER_CPU_H