diff --git a/hp-core/src/main.rs b/hp-core/src/main.rs
index ca198f5..5e9e92b 100644
--- a/hp-core/src/main.rs
+++ b/hp-core/src/main.rs
@@ -19,6 +19,7 @@ use esp_hal::{
     gpio::lp_io::LowPowerOutput,
     load_lp_code,
     lp_core::{LpCore, LpCoreWakeupSource},
+    rtc_cntl::{Rtc, sleep::WakeFromLpCoreWakeupSource},
     main,
 };
 use esp_println::{print, println};
@@ -28,12 +29,14 @@ fn main() -> ! {
     let peripherals = esp_hal::init(esp_hal::Config::default());
 
     // configure GPIO 1 as LP output pin
-
     let lp_pin = LowPowerOutput::new(peripherals.GPIO1);
 
+    let mut rtc = Rtc::new(peripherals.LPWR);
+    let reason = WakeFromLpCoreWakeupSource::default();
+
     let mut lp_core = LpCore::new(peripherals.LP_CORE);
     lp_core.stop();
-    println!("lp core stopped");
+    println!("lp-core -> stop");
 
     // load code to LP core
     let lp_core_code =
@@ -41,12 +44,19 @@ fn main() -> ! {
 
     // start LP core
     lp_core_code.run(&mut lp_core, LpCoreWakeupSource::HpCpu, lp_pin);
-    println!("lpcore run");
+    println!("lpcore -> run");
 
+    let mut last: u32 = 0;
     let data = (0x5000_2000) as *mut u32;
     loop {
-        print!("Current {:x}           \u{000d}", unsafe {
+        let read = unsafe {
             data.read_volatile()
-        });
+        };
+        if last != read {
+            print!("Current {:x}           \u{000d}", read);
+            last = read;
+        }
+        println!("hp-core -> deep sleep");
+        rtc.sleep_light(&[&reason]);
     }
 }