diff --git a/src/i2c_slave.rs b/src/i2c_slave.rs
new file mode 100644
index 0000000..63b31b0
--- /dev/null
+++ b/src/i2c_slave.rs
@@ -0,0 +1,23 @@
+use ch32_hal::{
+        self as hal,
+        i2c::{SclPin, SdaPin},
+        Peripheral,
+    };
+use panic_halt as _;
+
+use core::marker::PhantomData;
+use hal::i2c::Instance;
+
+pub struct I2cSlave<'d, T: Instance> {
+    _phantom: PhantomData<&'d mut T>,
+}
+
+impl<'d, T: Instance> I2cSlave<'d, T> {
+    pub fn new(
+        peri: impl Peripheral<P = T> + 'd,
+        scl: impl Peripheral<P = impl SclPin<T>> + 'd,
+        sda: impl Peripheral<P = impl SdaPin<T>> + 'd,
+    ) -> Self {
+        todo!()
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 6615854..3b2a650 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,8 @@
 #![feature(type_alias_impl_trait)]
 #![feature(impl_trait_in_assoc_type)]
 
+mod i2c_slave;
+
 use embassy_executor::Spawner;
 use embassy_time::Timer;
 use hal::bind_interrupts;