1 files changed, 98 insertions, 0 deletions
diff --git a/src/channel.rs b/src/channel.rs
new file mode 100644
index 0000000..df23c39
--- /dev/null
+++ b/src/channel.rs
@@ -0,0 +1,98 @@
+//! ADC input channels
+use crate::{ic, Ads1x1x, BitFlags as BF, Config};
+
+mod private {
+    pub trait Sealed {}
+}
+
+/// Marker type for an ADC input channel.
+pub trait ChannelId<T>: private::Sealed {
+    /// Get the channel.
+    fn channel_id() -> ChannelSelection;
+}
+
+macro_rules! impl_channels {
+    ($(#[doc = $doc:expr] $CH:ident => [$($IC:ident),+]),+ $(,)?) => {
+        #[derive(Debug, Clone, Copy)]
+        /// ADC input channel selection.
+        pub enum ChannelSelection {
+            $(
+                #[doc = $doc]
+                $CH,
+            )+
+        }
+
+        $(
+            #[doc = $doc]
+            pub struct $CH;
+
+            impl private::Sealed for $CH {}
+
+            $(
+                impl<DI, CONV, MODE> ChannelId<Ads1x1x<DI, ic::$IC, CONV, MODE>> for $CH {
+                    fn channel_id() -> ChannelSelection {
+                        ChannelSelection::$CH
+                    }
+                }
+            )+
+        )+
+    };
+}
+
+impl_channels!(
+    /// Measure signal on input channel 0 differentially to signal on input channel 1.
+    DifferentialA0A1 => [Ads1013, Ads1014, Ads1015, Ads1113, Ads1114,  Ads1115],
+    /// Measure signal on input channel 0 differentially to signal on input channel 3.
+    DifferentialA0A3 => [Ads1015, Ads1115],
+    /// Measure signal on input channel 1 differentially to signal on input channel 3.
+    DifferentialA1A3 => [Ads1015, Ads1115],
+    /// Measure signal on input channel 3 differentially to signal on input channel 3.
+    DifferentialA2A3 => [Ads1015, Ads1115],
+    /// Measure single-ended signal on input channel 0.
+    SingleA0 => [Ads1015, Ads1115],
+    /// Measure single-ended signal on input channel 1.
+    SingleA1 => [Ads1015, Ads1115],
+    /// Measure single-ended signal on input channel 2.
+    SingleA2 => [Ads1015, Ads1115],
+    /// Measure single-ended signal on input channel 3.
+    SingleA3 => [Ads1015, Ads1115]
+);
+
+impl Config {
+    pub(crate) fn with_mux_bits(&self, ch: ChannelSelection) -> Self {
+        match ch {
+            ChannelSelection::DifferentialA0A1 => self
+                .with_low(BF::MUX2)
+                .with_low(BF::MUX1)
+                .with_low(BF::MUX0),
+            ChannelSelection::DifferentialA0A3 => self
+                .with_low(BF::MUX2)
+                .with_low(BF::MUX1)
+                .with_high(BF::MUX0),
+            ChannelSelection::DifferentialA1A3 => self
+                .with_low(BF::MUX2)
+                .with_high(BF::MUX1)
+                .with_low(BF::MUX0),
+            ChannelSelection::DifferentialA2A3 => self
+                .with_low(BF::MUX2)
+                .with_high(BF::MUX1)
+                .with_high(BF::MUX0),
+            ChannelSelection::SingleA0 => self
+                .with_high(BF::MUX2)
+                .with_low(BF::MUX1)
+                .with_low(BF::MUX0),
+            ChannelSelection::SingleA1 => self
+                .with_high(BF::MUX2)
+                .with_low(BF::MUX1)
+                .with_high(BF::MUX0),
+            ChannelSelection::SingleA2 => self
+                .with_high(BF::MUX2)
+                .with_high(BF::MUX1)
+                .with_low(BF::MUX0),
+            ChannelSelection::SingleA3 => self
+                .with_high(BF::MUX2)
+                .with_high(BF::MUX1)
+                .with_high(BF::MUX0),
+        }
+    }
+}