diff --git a/.gitmodules b/.gitmodules
index 8c705909..32a0783a 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -7,3 +7,6 @@
 [submodule "examples/testusbhostFAT/Arduino_Makefile_master"]
 	path = examples/testusbhostFAT/Arduino_Makefile_master
 	url = https://github.com/xxxajk/Arduino_Makefile_master
+[submodule "examples/testusbhostFAT/RTClib"]
+	path = examples/testusbhostFAT/RTClib
+	url = https://github.com/xxxajk/RTClib
diff --git a/examples/testusbhostFAT/RTClib b/examples/testusbhostFAT/RTClib
new file mode 160000
index 00000000..2f260cd0
--- /dev/null
+++ b/examples/testusbhostFAT/RTClib
@@ -0,0 +1 @@
+Subproject commit 2f260cd0f3c7817256a3e029d34b155d839785c8