diff --git a/semestralka_2/build.rs b/semestralka_2/build.rs
index 6e6dd89..bc6641f 100644
--- a/semestralka_2/build.rs
+++ b/semestralka_2/build.rs
@@ -1,5 +1,6 @@
 // build.rs
 
+use std::env;
 use std::path::PathBuf;
 
 fn main() {
@@ -25,6 +26,7 @@ fn main() {
         "stm32u5xx_hal_ramcfg.c",
         "stm32u5xx_hal_rtc.c",
         "stm32u5xx_hal_rtc_ex.c",
+        "stm32u5xx_hal_iwdg.c",
     ];
 
     let mut build = cc::Build::new();
@@ -42,6 +44,7 @@ fn main() {
         .include(&example_inc)
         .define("USE_HAL_DRIVER", None)
         .define("STM32U575xx", None)
+        .define("HAL_IWDG_MODULE_ENABLED", None)
         .flag("-mthumb")
         .flag("-march=armv8-m.main+fp.dp")
         .flag("-mfloat-abi=hard")
diff --git a/semestralka_2/src/bin/main.rs b/semestralka_2/src/bin/main.rs
index ae994b5..5047815 100644
--- a/semestralka_2/src/bin/main.rs
+++ b/semestralka_2/src/bin/main.rs
@@ -3,11 +3,15 @@
 #![no_main]
 
 use defmt::*;
+use core::ptr::addr_of_mut;
+use embassy_stm32::pac;
 use embassy_executor::Spawner;
 use embassy_futures::yield_now;
 use embassy_stm32::bind_interrupts;
 use embassy_stm32::peripherals;
 use embassy_stm32::usart::{BufferedUart, Config, BufferedInterruptHandler};
+use embassy_stm32::gpio::{Output, Level, Speed};
+use embassy_time::{Duration, Timer};
 
 use static_cell::StaticCell;
 use dma_gpio::config::{
@@ -23,13 +27,20 @@ bind_interrupts!(struct Irqs {
 unsafe extern "C" {
     fn HAL_Init();
     fn HAL_PWR_EnterSTANDBYMode();
-    fn HAL_PWREx_EnterSHUTDOWNMode();
+    fn HAL_IWDG_Init(handle: *mut ());
+    fn HAL_IWDG_Refresh(handle: *mut ());
+    fn __HAL_PWR_GET_FLAG(flag: u32) -> u32;
+    fn __HAL_PWR_CLEAR_FLAG(flag: u32);
 }
 
+const PWR_FLAG_SBF: u32 = 1 << 1;
+static mut IWDG_HANDLE: [u8; 64] = [0; 64];
+
 #[embassy_executor::main]
 async fn main(spawner: Spawner) {
     info!("boot");
     let p = embassy_stm32::init(Default::default());
+    let mut led = Output::new(p.PB0, Level::Low, Speed::Low);
     info!("init m8");
 
     // HARDWARE UART to the PC
@@ -50,18 +61,35 @@ async fn main(spawner: Spawner) {
     spawner.spawn(uart_task(uart, &PIPE_HW_TX, &PIPE_HW_RX).unwrap());
     // END OF HARDWARE UART to the PC
 
-    unsafe {
-        HAL_Init();
-        HAL_PWR_EnterSTANDBYMode();
+    let pwr = pac::PWR;
 
-        // Example 2 (unreachable if above executes): enter Shutdown
-        // HAL_PWREx_EnterSHUTDOWNMode();
+    let from_standby = pwr.sr().read().sbf();
+    if from_standby {
+        info!("Wake from Standby");
+        pwr.sr().write(|w| w.set_sbf(true));
     }
+    info!("Iwdg 1 init");
+    info!("Iwdg 1 init");
+    unsafe {
+        HAL_IWDG_Init(addr_of_mut!(IWDG_HANDLE) as *mut ());
+    }
+    info!("Iwdg 2 init");
+    info!("Iwdg 2 init");
+    info!("Iwdg 2 init");
+    info!("Iwdg 2 init");
+    info!("Iwdg 2 init");
     loop {
         info!("tick start");
-        // Timer::after(Duration::from_millis(100)).await;
+        led.set_high();
+        Timer::after(Duration::from_secs(1)).await;
         // info!("tick end");
 
+        unsafe {
+            info!("Standby...");
+            led.set_low();
+            HAL_IWDG_Refresh(addr_of_mut!(IWDG_HANDLE) as *mut ());
+            HAL_PWR_EnterSTANDBYMode();
+        }
 
         yield_now().await;
     }