diff --git a/src/ds323x/configuration.rs b/src/ds323x/configuration.rs
index 6d61dbc..d0b12c0 100644
--- a/src/ds323x/configuration.rs
+++ b/src/ds323x/configuration.rs
@@ -1,7 +1,7 @@
 //! Device configuration
 
 extern crate embedded_hal as hal;
-use super::super::{ Ds323x, Register, BitFlags, Error };
+use super::super::{ Ds323x, SqWFreq, Register, BitFlags, Error };
 use interface::{ ReadData, WriteData };
 
 impl<DI, IC, E> Ds323x<DI, IC>
@@ -88,6 +88,19 @@ where
         let control = self.control;
         self.write_control(control & !BitFlags::BBSQW)
     }
+
+    /// Set the square-wave output frequency.
+    pub fn set_square_wave_frequency(&mut self, freq: SqWFreq) -> Result<(), Error<E>> {
+        let new_control;
+        match freq {
+            SqWFreq::_1Hz     => new_control = self.control & !BitFlags::RS2 & !BitFlags::RS1,
+            SqWFreq::_1_024Hz => new_control = self.control & !BitFlags::RS2 |  BitFlags::RS1,
+            SqWFreq::_4_096Hz => new_control = self.control |  BitFlags::RS2 & !BitFlags::RS1,
+            SqWFreq::_8_192Hz => new_control = self.control |  BitFlags::RS2 |  BitFlags::RS1,
+        }
+        self.write_control(new_control)
+    }
+
     fn write_control(&mut self, control: u8) -> Result<(), Error<E>> {
         self.iface.write_register(Register::CONTROL, control)?;
         self.control = control;
diff --git a/src/lib.rs b/src/lib.rs
index 2991421..ddb7a1e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -333,6 +333,19 @@ pub enum Error<E> {
     InvalidInputData
 }
 
+/// Square-wave output frequency
+#[derive(Debug, Clone, PartialEq)]
+pub enum SqWFreq {
+    /// 1 Hz
+    _1Hz,
+    /// 1.024 Hz
+    _1_024Hz,
+    /// 4.096 Hz
+    _4_096Hz,
+    /// 8.192 Hz
+    _8_192Hz,
+}
+
 struct Register;
 
 impl Register {
@@ -358,6 +371,8 @@ impl BitFlags {
     const EOSC       : u8 = 0b1000_0000;
     const BBSQW      : u8 = 0b0100_0000;
     const TEMP_CONV  : u8 = 0b0010_0000;
+    const RS2        : u8 = 0b0001_0000;
+    const RS1        : u8 = 0b0000_1000;
     const INTCN      : u8 = 0b0000_0100;
     const BUSY       : u8 = 0b0000_0100;
     const EN32KHZ    : u8 = 0b0000_1000;
diff --git a/tests/common/mod.rs b/tests/common/mod.rs
index 5bd1da2..07509ad 100644
--- a/tests/common/mod.rs
+++ b/tests/common/mod.rs
@@ -31,6 +31,8 @@ impl BitFlags {
     pub const EOSC       : u8 = 0b1000_0000;
     pub const BBSQW      : u8 = 0b0100_0000;
     pub const TEMP_CONV  : u8 = 0b0010_0000;
+    pub const RS2        : u8 = 0b0001_0000;
+    pub const RS1        : u8 = 0b0000_1000;
     pub const INTCN      : u8 = 0b0000_0100;
     pub const BUSY       : u8 = 0b0000_0100;
     pub const EN32KHZ    : u8 = 0b0000_1000;
diff --git a/tests/configuration.rs b/tests/configuration.rs
index cb0f9f4..e2ac1be 100644
--- a/tests/configuration.rs
+++ b/tests/configuration.rs
@@ -3,6 +3,10 @@
 extern crate embedded_hal_mock as hal;
 use hal::i2c::Transaction as I2cTrans;
 use hal::spi::Transaction as SpiTrans;
+
+extern crate ds323x;
+use ds323x::SqWFreq;
+
 mod common;
 use common::{ DEVICE_ADDRESS as DEV_ADDR, Register, new_ds3231,
               new_ds3232, new_ds3234, destroy_ds3231, destroy_ds3232,
@@ -65,3 +69,8 @@ call_method_test!(int_sqw_out_sqw, use_int_sqw_output_as_square_wave, CONTROL, C
 call_method_test!(enable_sqw,  enable_square_wave,  CONTROL, CONTROL_POR_VALUE |  BF::BBSQW);
 call_method_test!(disable_sqw, disable_square_wave, CONTROL, CONTROL_POR_VALUE & !BF::BBSQW);
 
+set_param_test!(set_sqw_freq_1,     set_square_wave_frequency, CONTROL, SqWFreq::_1Hz,     CONTROL_POR_VALUE & !BF::RS2 & !BF::RS1);
+set_param_test!(set_sqw_freq_1_024, set_square_wave_frequency, CONTROL, SqWFreq::_1_024Hz, CONTROL_POR_VALUE & !BF::RS2 |  BF::RS1);
+set_param_test!(set_sqw_freq_4_096, set_square_wave_frequency, CONTROL, SqWFreq::_4_096Hz, CONTROL_POR_VALUE |  BF::RS2 & !BF::RS1);
+set_param_test!(set_sqw_freq_8_192, set_square_wave_frequency, CONTROL, SqWFreq::_8_192Hz, CONTROL_POR_VALUE |  BF::RS2 |  BF::RS1);
+