diff --git a/pycardium/mphalport.c b/pycardium/mphalport.c
index b17e9ca3245a120b69b16a319ce2896ffc5c391c..ede4bae73dce2b505cc8f00d8430a5d7b9df7d73 100644
--- a/pycardium/mphalport.c
+++ b/pycardium/mphalport.c
@@ -20,9 +20,13 @@
 #include <stdio.h>
 #include <string.h>
 
-// Smallest interval which can be reached exactly
-// * 8 to allow up to 100 ms epic calls
-#define SYSTICK_INTERVAL_US (15625ULL * 8ULL)
+/* Smallest integer us interval which can be reached exactly due
+ * to the 32768 Hz systick frequency */
+#define SYSTICK_INTERVAL_US_MIN 15625
+
+/* Target systick interval is 1 second */
+#define SYSTICK_INTERVAL_US                                                    \
+	(SYSTICK_INTERVAL_US_MIN * (1000000 / SYSTICK_INTERVAL_US_MIN))
 
 /*
  * Copied from core_cm4.h and modified to select the