diff --git a/.gitmodules b/.gitmodules
index c1d393e..41bbf17 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -16,3 +16,6 @@
 [submodule "test/libraries/mma8451"]
 	path = test/libraries/mma8451
 	url = https://github.com/adafruit/Adafruit_CircuitPython_MMA8451.git
+[submodule "test/libraries/register"]
+	path = test/libraries/register
+	url = https://github.com/adafruit/Adafruit_CircuitPython_Register.git
diff --git a/test/libraries/register b/test/libraries/register
new file mode 160000
index 0000000..f86b454
--- /dev/null
+++ b/test/libraries/register
@@ -0,0 +1 @@
+Subproject commit f86b4549c1f8ec10682cb5e5148693dc29c85602