diff --git a/src/arch/msp430fr5994lp/arch.cc b/src/arch/msp430fr5994lp/arch.cc
index 024b2460b540e040eb4be7278c88b41199f0d58a..4edab894f4a36160fc63a5d9273c68d88b579c37 100644
--- a/src/arch/msp430fr5994lp/arch.cc
+++ b/src/arch/msp430fr5994lp/arch.cc
@@ -52,7 +52,7 @@ void Arch::setup(void)
 	CSCTL0_H = 0;
 
 
-#if defined(WITH_LOOP) || F_CPU == 72368UL
+#if defined(WITH_LOOP) || F_CPU == 32768UL
 	// enable LXFT for RTC
 	CSCTL0_H = CSKEY >> 8;
 	CSCTL4 &= ~LFXTOFF;