commit 7dcefbebb6c492b4e2db3d8d43d834cc4e5b068a
Author: Grigorios Giotas <grigorios.giotas@proton.me>
Date:   Sun Oct 23 10:21:11 2022 +0200

    initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4fffb2f
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/target
+/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..2ed2e80
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "k8056"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..d75ee9f
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,83 @@
+pub mod uart {
+    use std::convert::TryFrom;
+
+    #[derive(Debug)]
+    pub struct IndexError(pub u8);
+
+    #[derive(Debug, PartialEq, Eq, Clone, Copy)]
+    pub struct Idx {
+        relay_number: u8,
+    }
+
+    impl Idx {
+        pub fn new(value: u8) -> Self {
+            Self::try_from(value).unwrap()
+        }
+
+        pub fn as_byte(&self) -> u8 {
+            b'0' + self.relay_number
+        }
+    }
+
+    impl TryFrom<u8> for Idx {
+        type Error = IndexError;
+        fn try_from(x: u8) -> Result<Self, Self::Error> {
+            if x < 1 || x > 9 {
+                Err(IndexError(x))
+            } else {
+                Ok(Idx { relay_number: x })
+            }
+        }
+    }
+
+    #[derive(Debug, Clone, PartialEq, Eq)]
+    pub enum Command {
+        // Emergency stop all cards, regardless of address
+        Emergency, // E
+        // Display address
+        Display, // D
+        // Set a relay
+        Set(Idx), // S
+        // Clear a relay
+        Clear(Idx), // C
+        // Toggle a relay
+        Toggle(Idx), // T
+        // Change the current address of a card
+        Address(Idx), // A
+        // Force all cards to address 1 (default)
+        Force, // F
+        // Send a byte
+        Byte(u8), // B
+    }
+
+    impl Command {
+        pub fn to_bytes(&self, address: u8) -> [u8; 5] {
+            let (cmd, idx) = self.as_tuple();
+            let mut buf = [13, address, cmd, idx, 0];
+            buf[4] = buf[0..=3].iter().fold(0, |a, x| a.overflowing_sub(*x).0);
+            buf
+        }
+
+        fn as_tuple(&self) -> (u8, u8) {
+            match *self {
+                Command::Emergency => (b'E', 0),
+                Command::Display => (b'D', 0),
+                Command::Set(x) => (b'S', x.as_byte()),
+                Command::Clear(x) => (b'C', x.as_byte()),
+                Command::Toggle(x) => (b'T', x.as_byte()),
+                Command::Address(x) => (b'A', x.as_byte()),
+                Command::Force => (b'F', 0),
+                Command::Byte(x) => (b'B', x),
+            }
+        }
+    }
+}
+
+
+#[cfg(test)]
+mod tests {
+    // use super::*;
+
+    // #[test]
+
+}