Merge pull request #1 from FloppyDisck/initial_impl

Initial implementation

Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "i2c-multiplexer"
+description = "An I2C Multiplexer library that supports the PCA9546 and TCA9546A chips"
+version = "0.1.0"
+edition = "2021"
+license = "MIT"
+repository = "https://github.com/FloppyDisck/i2c-multiplexer"
+readme = "README.md"
+keywords = ["embedded", "multiplexer", "PCA9546", "TCA9546A"]
+categories = ["embedded"]
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+embedded-svc            = "0.22.0"
+embedded-hal            = "0.2.7"
+
+crc = "3.0.0"
+thiserror = "1.0.38"
+
+[dev-dependencies]
+embedded-hal-mock = "0.9.0"
+rstest = "0.16.0"

README.md

@@ -1,2 +1,43 @@
-# i2c-multiplexer
+# I2C-Multiplexer   [![Build Status]][actions] [![Latest Version]][crates.io]
+[Build Status]: https://img.shields.io/github/actions/workflow/status/FloppyDisck/i2c-multiplexer/rust.yml?branch=main
+[actions]: https://github.com/FloppyDisck/i2c-multiplexer/actions?query=branch%3Amain
+[Latest Version]: https://img.shields.io/crates/v/i2c-multiplexer.svg
+[crates.io]: https://crates.io/crates/i2c-multiplexer
 An I2C Multiplexer library that supports the PCA9546 and TCA9546A chips
+
+---
+
+## Usage
+The sensor is initialized 
+```rust
+use i2c_multiplexer::prelude::*;
+
+fn main() -> Result<()> {
+    // Disable all ports and only enable port 0
+    Multiplexer::new(i2c).with_ports_disabled()?.set_port(0, true)?;
+}
+```
+
+## Changing Address
+```rust
+use i2c_multiplexer::prelude::*;
+
+fn main() -> Result<()> {
+    // Manually set the address
+    Multiplexer::new(i2c).with_address(0x72);
+
+    // Or set it according to the selected hardware pins
+    // This uses A0 which means the address is 0x71
+    Multiplexer::new(i2c).with_address_pins(true, false, false);
+}
+```
+
+## Setting multiple ports
+```rust
+use i2c_multiplexer::prelude::*;
+
+fn main() -> Result<()> {
+    // Manually set the ports 0,2 to enabled and 1,3 to disabled
+    Multiplexer::new(i2c).with_ports([true, false, true, false])?;
+}
+```

src/error.rs

@@ -0,0 +1,13 @@
+use thiserror::Error;
+
+pub type Result<T> = std::result::Result<T, MultiplexerError>;
+
+#[derive(Error, Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq)]
+pub enum MultiplexerError {
+    #[error("Write Read I2C Error")]
+    WriteReadI2CError,
+    #[error("Write I2C Error")]
+    WriteI2CError,
+    #[error("Incorrect port supplies")]
+    PortError,
+}

src/lib.rs

@@ -0,0 +1,175 @@
+pub mod error;
+
+use embedded_hal::blocking::i2c;
+use error::{MultiplexerError, Result};
+
+pub mod prelude {
+    pub use crate::{error::MultiplexerError, Multiplexer, PortState};
+}
+
+#[derive(Copy, Clone, Debug)]
+pub enum PortState {
+    Enabled,
+    Disabled,
+}
+
+impl From<bool> for PortState {
+    fn from(value: bool) -> Self {
+        match value {
+            true => PortState::Enabled,
+            false => PortState::Disabled,
+        }
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+pub struct Multiplexer<I2C: 'static + Send + Sync> {
+    i2c: I2C,
+    address: u8,
+    state: [bool; 4],
+}
+
+impl<I2C> Multiplexer<I2C>
+where
+    I2C: i2c::WriteRead + i2c::Write + Send + Sync,
+{
+    pub fn new(i2c: I2C) -> Self {
+        Self {
+            i2c,
+            address: 0x70,
+            state: [false; 4],
+        }
+    }
+
+    /// Sets the address according to the enabled hardware settings
+    pub fn with_address_pins(mut self, a0: bool, a1: bool, a2: bool) -> Self {
+        self.address = 0b1110_0000;
+        if a0 {
+            self.address |= 0b0000_0001;
+        }
+        if a1 {
+            self.address |= 0b0000_0010;
+        }
+        if a2 {
+            self.address |= 0b0000_0100;
+        }
+        self
+    }
+
+    /// Sets the address
+    pub fn with_address(mut self, address: u8) -> Self {
+        self.address = address;
+        self
+    }
+
+    fn port_code(states: [bool; 4]) -> u8 {
+        let mut code = 0;
+        if states[0] {
+            code |= 0b000_0001;
+        }
+        if states[1] {
+            code |= 0b000_0010;
+        }
+        if states[2] {
+            code |= 0b000_0100;
+        }
+        if states[3] {
+            code |= 0b000_1000;
+        }
+
+        code
+    }
+}
+
+impl<I2C> Multiplexer<I2C>
+where
+    I2C: i2c::WriteRead + i2c::Write + Send + Sync,
+{
+    /// Disables all ports
+    pub fn with_ports_disabled(self) -> Result<Self> {
+        self.with_ports([false; 4])
+    }
+
+    /// Disables all ports
+    pub fn set_ports_disabled(mut self) -> Result<()> {
+        self.set_ports([false; 4])
+    }
+
+    /// Enables all ports
+    pub fn with_ports_enabled(self) -> Result<Self> {
+        self.with_ports([true; 4])
+    }
+
+    /// Enables all ports
+    pub fn set_ports_enabled(mut self) -> Result<()> {
+        self.set_ports([true; 4])
+    }
+
+    /// Enables / Disables the selected port
+    pub fn set_port(&mut self, port: u8, state: impl Into<bool>) -> Result<()> {
+        if port >= 4 {
+            return Err(MultiplexerError::PortError);
+        }
+
+        self.state[port as usize] = state.into();
+
+        let code = Self::port_code(self.state);
+
+        self.i2c_write(&[code])
+    }
+
+    /// Sets the selected port
+    pub fn with_port(mut self, port: u8, state: impl Into<bool>) -> Result<Self> {
+        self.set_port(port, state.into())?;
+        Ok(self)
+    }
+
+    /// Enables / Disables the selected ports
+    pub fn set_ports(&mut self, ports: [bool; 4]) -> Result<()> {
+        let code = Self::port_code(ports);
+        self.i2c_write(&[code])
+    }
+
+    /// Enables / Disables the selected ports
+    pub fn with_ports(mut self, ports: [bool; 4]) -> Result<Self> {
+        self.set_ports(ports)?;
+        Ok(self)
+    }
+
+    fn i2c_write(&mut self, bytes: &[u8]) -> Result<()> {
+        match self.i2c.write(self.address, bytes) {
+            Ok(res) => Ok(res),
+            Err(_) => Err(MultiplexerError::WriteI2CError),
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::prelude::*;
+    use embedded_hal_mock::i2c::Mock;
+    use rstest::*;
+
+    #[rstest]
+    #[case([true;4], 0b0000_1111)]
+    #[case([false;4], 0b0000_0000)]
+    #[case([true, false, true, false], 0b0000_0101)]
+    fn setup_ports(#[case] ports: [bool; 4], #[case] result: u8) {
+        assert_eq!(Multiplexer::<Mock>::port_code(ports), result)
+    }
+
+    #[rstest]
+    #[case([true;3], 0b1110_0111)]
+    #[case([false;3], 0b1110_0000)]
+    #[case([true, false, false], 0b1110_0001)]
+    #[case([false, true, false], 0b1110_0010)]
+    #[case([true, false, true], 0b1110_0101)]
+    fn setup_address(#[case] addr: [bool; 3], #[case] result: u8) {
+        assert_eq!(
+            Multiplexer::new(Mock::new([]))
+                .with_address_pins(addr[0], addr[1], addr[2])
+                .address,
+            result
+        )
+    }
+}