diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..c172f82
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "3rd/mbed-os"]
+	path = 3rd/mbed-os
+	url = git@github.com:ARMmbed/mbed-os.git
diff --git a/3rd/mbed-os b/3rd/mbed-os
new file mode 160000
index 0000000..5c8e60f
--- /dev/null
+++ b/3rd/mbed-os
@@ -0,0 +1 @@
+Subproject commit 5c8e60f80be658d65fbb78a70514d83c23d60a7a