Add support for channel selection

5 files changed, 73 insertions, 6 deletions

diff --git a/src/devices/ads1x1x/mode/oneshot.rs b/src/devices/ads1x1x/mode/oneshot.rs
index 0da4a7b..7ff9ac9 100644
--- a/src/devices/ads1x1x/mode/oneshot.rs
+++ b/src/devices/ads1x1x/mode/oneshot.rs
@@ -3,7 +3,8 @@
 use core::marker::PhantomData;
 use { Ads1x1x, mode, Error, Register, BitFlags, Config, ic };
 use { interface, hal, nb };
-use super::super::OperatingMode;
+use devices::ads1x1x::OperatingMode;
+use devices::channels::ChannelSelection;
 use super::convert_measurement;
 
 impl<DI, IC, E> Ads1x1x<DI, IC, mode::OneShot>
@@ -30,8 +31,8 @@ where
         Ok(!config.is_high(BitFlags::OS))
     }
 
-    fn trigger_measurement(&mut self) -> Result<(), Error<E>> {
-        let config = self.config.with_high(BitFlags::OS);
+    fn trigger_measurement(&mut self, config: &Config) -> Result<(), Error<E>> {
+        let config = config.with_high(BitFlags::OS);
         self.iface.write_register(Register::CONFIG, config.bits)
     }
 }
@@ -40,7 +41,7 @@ impl<DI, IC, E, CH> hal::adc::OneShot<Ads1x1x<DI, IC, mode::OneShot>, i16, CH> f
 where
     DI: interface::ReadData<Error = E> + interface::WriteData<Error = E>,
     IC: ic::Resolution,
-    CH: hal::adc::Channel<Ads1x1x<DI, IC, mode::OneShot>>
+    CH: hal::adc::Channel<Ads1x1x<DI, IC, mode::OneShot>, ID = ChannelSelection>
 {
     type Error = Error<E>;
 
@@ -56,7 +57,9 @@ where
             self.a_conversion_was_started = false;
             return Ok(convert_measurement::<IC>(value));
         }
-        self.trigger_measurement().map_err(nb::Error::Other)?;
+        let config = self.config.with_mux_bits(CH::channel());
+        self.trigger_measurement(&config).map_err(nb::Error::Other)?;
+        self.config = config;
         self.a_conversion_was_started = true;
         Err(nb::Error::WouldBlock)
     }
diff --git a/src/devices/channels.rs b/src/devices/channels.rs
index 2482df5..c202ad3 100644
--- a/src/devices/channels.rs
+++ b/src/devices/channels.rs
@@ -1,5 +1,5 @@
 //! ADC input channels
-use { Ads1x1x, ic, hal };
+use { Ads1x1x, ic, hal, Config, BitFlags as BF };
 
 /// ADC input channel selection
 #[allow(dead_code)]
@@ -68,3 +68,19 @@ impl_channel!(Ads1115, SingleA0);
 impl_channel!(Ads1115, SingleA1);
 impl_channel!(Ads1115, SingleA2);
 impl_channel!(Ads1115, SingleA3);
+
+impl Config {
+    pub(crate) fn with_mux_bits(&self, ch: ChannelSelection) -> Self {
+        use self::ChannelSelection as CS;
+        match ch {
+            CS::DifferentialA0A1 => self.with_low( BF::MUX2).with_low( BF::MUX1).with_low( BF::MUX0),
+            CS::DifferentialA0A3 => self.with_low( BF::MUX2).with_low( BF::MUX1).with_high(BF::MUX0),
+            CS::DifferentialA1A3 => self.with_low( BF::MUX2).with_high(BF::MUX1).with_low( BF::MUX0),
+            CS::DifferentialA2A3 => self.with_low( BF::MUX2).with_high(BF::MUX1).with_high(BF::MUX0),
+            CS::SingleA0         => self.with_high(BF::MUX2).with_low( BF::MUX1).with_low( BF::MUX0),
+            CS::SingleA1         => self.with_high(BF::MUX2).with_low( BF::MUX1).with_high(BF::MUX0),
+            CS::SingleA2         => self.with_high(BF::MUX2).with_high(BF::MUX1).with_low( BF::MUX0),
+            CS::SingleA3         => self.with_high(BF::MUX2).with_high(BF::MUX1).with_high(BF::MUX0),
+        }
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 3170f20..ef016fb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -237,6 +237,9 @@ struct BitFlags;
 impl BitFlags {
     const OP_MODE      : u16 = 0b0000_0001_0000_0000;
     const OS           : u16 = 0b1000_0000_0000_0000;
+    const MUX2         : u16 = 0b0100_0000_0000_0000;
+    const MUX1         : u16 = 0b0010_0000_0000_0000;
+    const MUX0         : u16 = 0b0001_0000_0000_0000;
     const DR2          : u16 = 0b0000_0000_1000_0000;
     const DR1          : u16 = 0b0000_0000_0100_0000;
     const DR0          : u16 = 0b0000_0000_0010_0000;
diff --git a/tests/common/mod.rs b/tests/common/mod.rs
index ec63ec0..886967c 100644
--- a/tests/common/mod.rs
+++ b/tests/common/mod.rs
@@ -18,6 +18,9 @@ pub struct BitFlags;
 impl BitFlags {
     //pub const OP_MODE      : u16 = 0b0000_0001_0000_0000;
     pub const OS           : u16 = 0b1000_0000_0000_0000;
+    pub const MUX2         : u16 = 0b0100_0000_0000_0000;
+    pub const MUX1         : u16 = 0b0010_0000_0000_0000;
+    pub const MUX0         : u16 = 0b0001_0000_0000_0000;
     pub const DR2          : u16 = 0b0000_0000_1000_0000;
     pub const DR1          : u16 = 0b0000_0000_0100_0000;
     pub const DR0          : u16 = 0b0000_0000_0010_0000;
@@ -71,6 +74,7 @@ macro_rules! impl_new_destroy {
 impl_new_destroy!(Ads1013, new_ads1013, destroy_ads1013, I2cTrans, interface::I2cInterface<I2cMock>);
 impl_new_destroy!(Ads1113, new_ads1113, destroy_ads1113, I2cTrans, interface::I2cInterface<I2cMock>);
 impl_new_destroy!(Ads1014, new_ads1014, destroy_ads1014, I2cTrans, interface::I2cInterface<I2cMock>);
+impl_new_destroy!(Ads1015, new_ads1015, destroy_ads1015, I2cTrans, interface::I2cInterface<I2cMock>);
 
 #[macro_export]
 macro_rules! assert_would_block {
diff --git a/tests/mux_i2c.rs b/tests/mux_i2c.rs
new file mode 100644
index 0000000..95f97a5
--- /dev/null
+++ b/tests/mux_i2c.rs
@@ -0,0 +1,41 @@
+#[macro_use(block)]
+extern crate nb;
+extern crate embedded_hal;
+extern crate embedded_hal_mock as hal;
+use hal::i2c::Transaction as I2cTrans;
+extern crate ads1x1x;
+use ads1x1x::channel;
+
+#[macro_use]
+mod common;
+use common::{ new_ads1015 as new, destroy_ads1015 as destroy,
+              DEVICE_ADDRESS as DEV_ADDR, Register, BitFlags as BF, Config };
+
+use embedded_hal::adc::OneShot;
+
+macro_rules! mux_test {
+    ($name:ident, $CS:ident, $config_bits:expr) => {
+        #[test]
+        fn $name() {
+            let default_config = Config::default();
+            let config = Config::default().with_high(BF::OS).with_high($config_bits);
+            let transactions = [ I2cTrans::write_read(DEV_ADDR, vec![Register::CONFIG], vec![default_config.msb(), default_config.lsb()]),
+                                 I2cTrans::write(DEV_ADDR, vec![Register::CONFIG, config.msb(), config.lsb()]),
+                                 I2cTrans::write_read(DEV_ADDR, vec![Register::CONFIG], vec![config.msb(), config.lsb()]),
+                                 I2cTrans::write_read(DEV_ADDR, vec![Register::CONVERSION], vec![0x80, 0x00] ) ];
+            let mut dev = new(&transactions);
+            let measurement = block!(dev.read(&mut channel::$CS)).unwrap();
+            assert_eq!(-2048, measurement);
+            destroy(dev);
+        }
+    };
+}
+
+mux_test!(diffa0a1, DifferentialA0A1, 0);
+mux_test!(diffa0a3, DifferentialA0A3, BF::MUX0);
+mux_test!(diffa1a3, DifferentialA1A3, BF::MUX1);
+mux_test!(diffa2a3, DifferentialA2A3, BF::MUX1 | BF::MUX0);
+mux_test!(singlea0, SingleA0, BF::MUX2);
+mux_test!(singlea1, SingleA1, BF::MUX2 | BF::MUX0);
+mux_test!(singlea2, SingleA2, BF::MUX2 | BF::MUX1);
+mux_test!(singlea3, SingleA3, BF::MUX2 | BF::MUX1 | BF::MUX0);