From d26de3893a300599f7336984d34b98d4c222e70b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc=20Poulhi=C3=A8s?= <dkm@kataplop.net>
Date: Sat, 18 Jul 2020 16:26:45 +0200
Subject: [PATCH] Initial work for interrupt driven alarms

Use INT pin from DS3231 for raising an interrupt.
---
 src/main.rs | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index b385b7d..f6dacbd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -20,7 +20,7 @@ extern crate ds323x;
 use ds323x::{Ds323x, NaiveTime, Rtcc};
 
 use tm4c123x_hal::gpio::GpioExt;
-use tm4c123x_hal::gpio::{Floating, AF2, AF3};
+use tm4c123x_hal::gpio::{InterruptMode, Floating, AF2, AF3};
 use tm4c123x_hal::i2c::I2c;
 use tm4c123x_hal::sysctl::{self, SysctlExt};
 use tm4c123x_hal::time::U32Ext;
@@ -110,6 +110,16 @@ fn main() -> ! {
     writeln!(stdout, "conf ds3231").unwrap();
     let mut rtc = Ds323x::new_ds3231(i2c_dev);
 
+    // we'll use interrupt
+    rtc.clear_alarm1_matched_flag().unwrap();
+    rtc.use_int_sqw_output_as_interrupt().unwrap();
+    rtc.enable_alarm1_interrupts().unwrap();
+
+    // GPIO for interrupt
+    // SQW pin wired to PD6
+    let mut pd6 = portd.pd6.into_pull_up_input();
+    pd6.set_interrupt_mode(InterruptMode::EdgeFalling);
+
     let time = NaiveTime::from_hms(23, 58, 45);
     rtc.set_time(&time).unwrap();