diff --git a/pkg/umorse/Makefile.dep b/pkg/umorse/Makefile.dep
new file mode 100644
index 0000000000..8871c3a908
--- /dev/null
+++ b/pkg/umorse/Makefile.dep
@@ -0,0 +1,3 @@
+ifneq (,$(filter umorse,$(USEPKG)))
+  USEMODULE += posix_time
+endif