diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..53bf3a4
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "io"]
+	path = io
+	url = git@git.blackmark.me:avr/io.git
diff --git a/README.md b/README.md
index e592e10..46d97f7 100644
--- a/README.md
+++ b/README.md
@@ -45,8 +45,8 @@ The PWM mode of the hardware timer can also be used. Additionally, if PWM is nee
 ## Goals
 
 - IO
-    - [ ] Interface for io-pins
-    - [ ] Interface for io-ports
+    - [x] Interface for io-pins
+    - [x] Interface for io-ports
     - [ ] Interface for mapping io-pins onto virtual io-ports, where the pins do not have to be located on the same hardware port
 - ADC
     - [ ] Support all hardware provided configuration options
diff --git a/io b/io
new file mode 160000
index 0000000..afbb1d0
--- /dev/null
+++ b/io
@@ -0,0 +1 @@
+Subproject commit afbb1d04239dbb2eee2095f4ee0807e626ea445d