diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..24ec7a8
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,4 @@
+[submodule "ecsim"]
+	path = ecsim
+	url = https://github.com/system76/ecsim.git
+	branch = master
diff --git a/Makefile b/Makefile
index bef42f7..18e9ad2 100644
--- a/Makefile
+++ b/Makefile
@@ -7,6 +7,9 @@ all: build/ec.rom
 clean:
 	rm -rf build
 
+sim: build/ec.rom
+	cargo run --release --manifest-path ecsim/Cargo.toml -- $<
+
 build/ec.rom: build/ec.ihx
 	mkdir -p build
 	makebin -p < $< > $@
diff --git a/ecsim b/ecsim
new file mode 160000
index 0000000..7e685cd
--- /dev/null
+++ b/ecsim
@@ -0,0 +1 @@
+Subproject commit 7e685cd81523da7e8479d51d547dc146e1957fd8