Add function to check if the oscillator has been stopped.

src/ds323x/status.rs

@@ -13,4 +13,11 @@ where
         let status = self.iface.read_register(Register::STATUS)?;
         Ok((status & BitFlags::BUSY) != 0)
     }
+
+    /// Read whether the oscillator is stopped or has been stopped at
+    /// some point.
+    pub fn has_been_stopped(&mut self) -> Result<bool, Error<E>> {
+        let status = self.iface.read_register(Register::STATUS)?;
+        Ok((status & BitFlags::OSC_STOP) != 0)
+    }
 }

src/lib.rs

@@ -296,6 +296,7 @@ impl BitFlags {
     const CENTURY    : u8 = 0b1000_0000;
     const EOSC       : u8 = 0b1000_0000;
     const BUSY       : u8 = 0b0000_0100;
+    const OSC_STOP   : u8 = 0b1000_0000;
 }
 
 const DEVICE_ADDRESS: u8 = 0b110_1000;

tests/common/mod.rs

@@ -26,6 +26,7 @@ pub struct BitFlags;
 impl BitFlags {
     pub const EOSC       : u8 = 0b1000_0000;
     pub const BUSY       : u8 = 0b0000_0100;
+    pub const OSC_STOP   : u8 = 0b1000_0000;
 }
 
 pub struct DummyOutputPin;

tests/status.rs

@@ -10,3 +10,6 @@ use common::{ DEVICE_ADDRESS as DEV_ADDR, Register, new_ds3231,
 
 get_param_test!(is_busy,     is_busy, STATUS, true,  0xFF);
 get_param_test!(is_not_busy, is_busy, STATUS, false, 0xFF & !BF::BUSY);
+
+get_param_test!(stopped,     has_been_stopped, STATUS, true,  0xFF);
+get_param_test!(not_stopped, has_been_stopped, STATUS, false, 0xFF & !BF::OSC_STOP);