Add methods to get/set the hours

README.md

@@ -8,6 +8,7 @@ extremely accurate real-time clocks, based on the [`embedded-hal`] traits.
 This driver allows you to:
 - Read/write the seconds.
 - Read/write the minutes.
+- Read/write the hours in 24h or AM/PM format.
 
 ## The devices
 

src/ds323x/datetime.rs

@@ -1,9 +1,20 @@
 //! Common implementation
 
 extern crate embedded_hal as hal;
-use super::super::{ Ds323x, Register, Error };
+use super::super::{ Ds323x, Register, BitFlags, Error };
 use interface::{ ReadRegister, WriteRegister };
 
+/// Hours in either 12-hour (AM/PM) or 24-hour format
+#[derive(Debug, Clone, PartialEq)]
+pub enum Hours {
+    /// AM [1-12]
+    AM(u8),
+    /// PM [1-12]
+    PM(u8),
+    /// 24H format [0-23]
+    H24(u8),
+}
+
 impl<DI, IC, E> Ds323x<DI, IC>
 where
     DI: ReadRegister<Error = E>
@@ -18,6 +29,24 @@ where
         self.read_register_decimal(Register::MINUTES)
     }
 
+    /// Read the hours.
+    pub fn get_hours(&mut self) -> Result<Hours, Error<E>> {
+        let data = self.iface.read_register(Register::HOURS)?;
+        self.get_hours_from_register(data)
+    }
+
+    fn get_hours_from_register(&self, data: u8) -> Result<Hours, Error<E>> {
+        if is_24h_format(data) {
+            Ok(Hours::H24(packed_bcd_to_decimal(data & !BitFlags::H24_H12)))
+        }
+        else if is_am(data) {
+            Ok(Hours::AM(packed_bcd_to_decimal(data & !(BitFlags::H24_H12 | BitFlags::AM_PM))))
+        }
+        else {
+            Ok(Hours::PM(packed_bcd_to_decimal(data & !(BitFlags::H24_H12 | BitFlags::AM_PM))))
+        }
+    }
+
     fn read_register_decimal(&mut self, register: u8) -> Result<u8, Error<E>> {
         let data = self.iface.read_register(register)?;
         Ok(packed_bcd_to_decimal(data))
@@ -48,11 +77,40 @@ where
         self.write_register_decimal(Register::MINUTES, minutes)
     }
 
+    /// Set the hours.
+    ///
+    /// Changes the operating mode to 12h/24h depending on the parameter.
+    ///
+    /// Will return an `Error::InvalidInputData` if the hours are out of range.
+    pub fn set_hours(&mut self, hours: Hours) -> Result<(), Error<E>> {
+        let value = self.get_hours_register_value(&hours)?;
+        self.iface.write_register(Register::HOURS, value)
+    }
+
+    fn get_hours_register_value(&mut self, hours: &Hours) -> Result<u8, Error<E>> {
+        match *hours {
+            Hours::H24(h) if h > 23 => Err(Error::InvalidInputData),
+            Hours::H24(h) => Ok(decimal_to_packed_bcd(h)),
+            Hours::AM(h) if h < 1 || h > 12 => Err(Error::InvalidInputData),
+            Hours::AM(h) =>  Ok(BitFlags::H24_H12 | decimal_to_packed_bcd(h)),
+            Hours::PM(h) if h < 1 || h > 12 => Err(Error::InvalidInputData),
+            Hours::PM(h) =>  Ok(BitFlags::H24_H12 | BitFlags::AM_PM | decimal_to_packed_bcd(h)),
+        }
+    }
+
     fn write_register_decimal(&mut self, register: u8, decimal_number: u8) -> Result<(), Error<E>> {
         self.iface.write_register(register, decimal_to_packed_bcd(decimal_number))
     }
 }
 
+fn is_24h_format(hours_data: u8) -> bool {
+    hours_data & BitFlags::H24_H12 == 0
+}
+
+fn is_am(hours_data: u8) -> bool {
+    hours_data & BitFlags::AM_PM == 0
+}
+
 // Transforms a decimal number to packed BCD format
 fn decimal_to_packed_bcd(dec: u8) -> u8 {
     ((dec / 10) << 4) | (dec % 10)

src/ds323x/mod.rs

@@ -1 +1,2 @@
 mod datetime;
+pub use self::datetime::Hours;

src/lib.rs

@@ -6,6 +6,7 @@
 //! This driver allows you to:
 //! - Read/write the seconds.
 //! - Read/write the minutes.
+//! - Read/write the hours in 24h or AM/PM format.
 //!
 //! ## The devices
 //!
@@ -179,6 +180,14 @@ struct Register;
 impl Register {
     const SECONDS   : u8 = 0x00;
     const MINUTES   : u8 = 0x01;
+    const HOURS     : u8 = 0x02;
+}
+
+struct BitFlags;
+
+impl BitFlags {
+    const H24_H12    : u8 = 0b0100_0000;
+    const AM_PM      : u8 = 0b0010_0000;
 }
 
 const DEVICE_ADDRESS: u8 = 0b110_1000;
@@ -265,3 +274,4 @@ where
 }
 
 mod ds323x;
+pub use ds323x::Hours;

tests/common/mod.rs

@@ -11,6 +11,7 @@ pub struct Register;
 impl Register {
     pub const SECONDS   : u8 = 0x00;
     pub const MINUTES   : u8 = 0x01;
+    pub const HOURS     : u8 = 0x02;
 }
 
 pub struct DummyOutputPin;

tests/ds323x.rs

@@ -6,6 +6,8 @@ use hal::spi::Transaction as SpiTrans;
 mod common;
 use common::{ DEVICE_ADDRESS, Register, new_ds3231,
               new_ds3232, new_ds3234 };
+extern crate ds323x;
+use ds323x::{ Hours };
 
 mod seconds {
     use super::*;
@@ -49,4 +51,25 @@ mod minutes {
 
     set_test!(can_set_ds3234, set_minutes, new_ds3234, 1,
             SpiTrans::write(vec![Register::MINUTES + 0x80, 1]));
+
+mod hours {
+    use super::*;
+    get_test!(can_get_ds3231, get_hours, new_ds3231, Hours::H24(21),
+            I2cTrans::write_read(DEVICE_ADDRESS, vec![Register::HOURS], vec![0b0010_0001]));
+
+    get_test!(can_get_ds3232, get_hours, new_ds3232, Hours::H24(21),
+            I2cTrans::write_read(DEVICE_ADDRESS, vec![Register::HOURS], vec![0b0010_0001]));
+
+    get_test!(can_get_ds3234, get_hours, new_ds3234, Hours::H24(21),
+            SpiTrans::transfer(vec![Register::HOURS, 0], vec![Register::HOURS, 0b0010_0001]));
+
+
+    set_test!(can_set_ds3231, set_hours, new_ds3231, Hours::H24(21),
+            I2cTrans::write(DEVICE_ADDRESS, vec![Register::HOURS, 0b0010_0001]));
+
+    set_test!(can_set_ds3232, set_hours, new_ds3232, Hours::H24(21),
+            I2cTrans::write(DEVICE_ADDRESS, vec![Register::HOURS, 0b0010_0001]));
+
+    set_test!(can_set_ds3234, set_hours, new_ds3234, Hours::H24(21),
+            SpiTrans::write(vec![Register::HOURS + 0x80, 0b0010_0001]));
 }