diff --git a/src/ds323x/alarms.rs b/src/ds323x/alarms.rs
index 6507275..7b7c702 100644
--- a/src/ds323x/alarms.rs
+++ b/src/ds323x/alarms.rs
@@ -18,6 +18,19 @@ pub struct DateAlarm1 {
     pub second: u8
 }
 
+/// Parameters for setting Alarm1 on a weekday
+#[derive(Debug, Clone, PartialEq)]
+pub struct WeekdayAlarm1 {
+    /// Weekday [1-7]
+    pub weekday: u8,
+    /// Hour
+    pub hour: Hours,
+    /// Minute [0-59]
+    pub minute: u8,
+    /// Second [0-59]
+    pub second: u8
+}
+
 /// Alarm1 trigger rate
 #[derive(Debug, Clone, PartialEq)]
 pub enum Alarm1Matching {
@@ -68,4 +81,22 @@ where
         self.iface.write_data(&mut data)
     }
 
+    /// Set Alarm1 for weekday.
+    ///
+    /// Will return an `Error::InvalidInputData` if any of the parameters is out of range.
+    pub fn set_alarm1_weekday(&mut self, when: WeekdayAlarm1, matching: Alarm1Matching) -> Result<(), Error<E>> {
+        if when.weekday < 1    || when.weekday > 7 ||
+           when.minute > 59 ||
+           when.second > 59 {
+            return Err(Error::InvalidInputData);
+        }
+        let match_mask = get_matching_mask_alarm1(matching);
+        let mut data = [ Register::ALARM1_SECONDS,
+                         decimal_to_packed_bcd(when.second)  | match_mask[0],
+                         decimal_to_packed_bcd(when.minute)  | match_mask[1],
+                         hours_to_register(&when.hour)?      | match_mask[2],
+                         decimal_to_packed_bcd(when.weekday) | match_mask[3] | BitFlags::WEEKDAY];
+        self.iface.write_data(&mut data)
+    }
+
 }
diff --git a/src/ds323x/mod.rs b/src/ds323x/mod.rs
index 62a7570..a2e7d98 100644
--- a/src/ds323x/mod.rs
+++ b/src/ds323x/mod.rs
@@ -1,7 +1,7 @@
 mod configuration;
 mod status;
 mod alarms;
-pub use self::alarms::{ DateAlarm1, Alarm1Matching };
+pub use self::alarms::{ DateAlarm1, WeekdayAlarm1, Alarm1Matching };
 mod datetime;
 pub use self::datetime::{ Hours, DateTime };
 use super::{ BitFlags, Error };
diff --git a/src/lib.rs b/src/lib.rs
index 9df2fe0..b15b257 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -474,6 +474,7 @@ impl BitFlags {
     const ALARM1F       : u8 = 0b0000_0001;
     const TEMP_CONV_BAT : u8 = 0b0000_0001;
     const ALARM_MATCH   : u8 = 0b1000_0000;
+    const WEEKDAY       : u8 = 0b0100_0000;
 }
 
 const DEVICE_ADDRESS   : u8 = 0b110_1000;
@@ -500,7 +501,7 @@ pub struct Ds323x<DI, IC> {
 
 pub mod interface;
 mod ds323x;
-pub use ds323x::{ Hours, DateTime, DateAlarm1, Alarm1Matching };
+pub use ds323x::{ Hours, DateTime, DateAlarm1, WeekdayAlarm1, Alarm1Matching };
 mod ds3231;
 mod ds3232;
 mod ds3234;
diff --git a/tests/alarms.rs b/tests/alarms.rs
index f5e344b..8636490 100644
--- a/tests/alarms.rs
+++ b/tests/alarms.rs
@@ -8,6 +8,7 @@ use common::{ DEVICE_ADDRESS as DEV_ADDR, Register, new_ds3231,
               new_ds3232, new_ds3234, destroy_ds3231, destroy_ds3232,
               destroy_ds3234, BitFlags as BF };
 extern crate ds323x;
+use ds323x::{ DateAlarm1, WeekdayAlarm1, Alarm1Matching as A1M, Hours, Error };
 use ds323x::{ DateAlarm1, Alarm1Matching as A1M, Hours, Error };
 
 #[macro_export]
@@ -44,6 +45,17 @@ mod alarm1 {
     set_invalid_alarm_test!(date_invalid_pm2, set_alarm1_date, DateAlarm1{ date: 1,  hour: Hours::PM(13),  minute: 1,  second: 1 },  A1M::AllMatch);
     set_invalid_alarm_test!(date_invalid_d1,  set_alarm1_date, DateAlarm1{ date: 0,  hour: Hours::H24(1),  minute: 1,  second: 1 },  A1M::AllMatch);
     set_invalid_alarm_test!(date_invalid_d2,  set_alarm1_date, DateAlarm1{ date: 32, hour: Hours::H24(1),  minute: 1,  second: 1 },  A1M::AllMatch);
+
+    set_invalid_alarm_test!(wd_invalid_s,   set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::H24(1),  minute: 1,  second: 60 }, A1M::AllMatch);
+    set_invalid_alarm_test!(wd_invalid_min, set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::H24(1),  minute: 60, second: 1 },  A1M::AllMatch);
+    set_invalid_alarm_test!(wd_invalid_h,   set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::H24(24), minute: 1,  second: 1 },  A1M::AllMatch);
+    set_invalid_alarm_test!(wd_invalid_am1, set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::AM(0),   minute: 1,  second: 1 },  A1M::AllMatch);
+    set_invalid_alarm_test!(wd_invalid_am2, set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::AM(13),  minute: 1,  second: 1 },  A1M::AllMatch);
+    set_invalid_alarm_test!(wd_invalid_pm1, set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::PM(0),   minute: 1,  second: 1 },  A1M::AllMatch);
+    set_invalid_alarm_test!(wd_invalid_pm2, set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::PM(13),  minute: 1,  second: 1 },  A1M::AllMatch);
+    set_invalid_alarm_test!(wd_invalid_d1,  set_alarm1_weekday, WeekdayAlarm1{ weekday: 0,  hour: Hours::H24(1),  minute: 1,  second: 1 },  A1M::AllMatch);
+    set_invalid_alarm_test!(wd_invalid_d2,  set_alarm1_weekday, WeekdayAlarm1{ weekday: 32, hour: Hours::H24(1),  minute: 1,  second: 1 },  A1M::AllMatch);
+}
 }
 
 macro_rules! _set_values_test {
@@ -97,3 +109,22 @@ mod alarm1_date {
     set_alarm_test!(match_ops, set_alarm1_date, DateAlarm1{ date: 1,  hour: Hours::H24(2), minute: 3, second: 4 }, A1M::OncePerSecond,
                     ALARM1_SECONDS, [AM | 4, AM | 3, AM | 2, AM | 1]);
 }
+
+mod alarm1_weekday {
+    use super::*;
+    set_alarm_test!(h24, set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::H24(2), minute: 3, second: 4 }, A1M::AllMatch,
+                    ALARM1_SECONDS, [4, 3, 2,           BF::WEEKDAY | 1]);
+    set_alarm_test!(am,  set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::AM(2),  minute: 3, second: 4 }, A1M::AllMatch,
+                    ALARM1_SECONDS, [4, 3, 0b0100_0010, BF::WEEKDAY | 1]);
+    set_alarm_test!(pm,  set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::PM(2),  minute: 3, second: 4 }, A1M::AllMatch,
+                    ALARM1_SECONDS, [4, 3, 0b0110_0010, BF::WEEKDAY | 1]);
+
+    set_alarm_test!(match_hms, set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::H24(2), minute: 3, second: 4 }, A1M::HoursMinutesAndSecondsMatch,
+                    ALARM1_SECONDS, [     4,      3,      2, AM | BF::WEEKDAY | 1]);
+    set_alarm_test!(match_ms,  set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::H24(2), minute: 3, second: 4 }, A1M::MinutesAndSecondsMatch,
+                    ALARM1_SECONDS, [     4,      3, AM | 2, AM | BF::WEEKDAY | 1]);
+    set_alarm_test!(match_s,   set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::H24(2), minute: 3, second: 4 }, A1M::SecondsMatch,
+                    ALARM1_SECONDS, [     4, AM | 3, AM | 2, AM | BF::WEEKDAY | 1]);
+    set_alarm_test!(match_ops, set_alarm1_weekday, WeekdayAlarm1{ weekday: 1,  hour: Hours::H24(2), minute: 3, second: 4 }, A1M::OncePerSecond,
+                    ALARM1_SECONDS, [AM | 4, AM | 3, AM | 2, AM | BF::WEEKDAY | 1]);
+}
diff --git a/tests/common/mod.rs b/tests/common/mod.rs
index 7ec452c..46a031a 100644
--- a/tests/common/mod.rs
+++ b/tests/common/mod.rs
@@ -52,6 +52,7 @@ impl BitFlags {
     pub const ALARM1F       : u8 = 0b0000_0001;
     pub const TEMP_CONV_BAT : u8 = 0b0000_0001;
     pub const ALARM_MATCH   : u8 = 0b1000_0000;
+    pub const WEEKDAY       : u8 = 0b0100_0000;
 }
 
 pub struct DummyOutputPin;