2 files changed, 42 insertions, 0 deletions

diff --git a/embassy-nrf/src/wdt.rs b/embassy-nrf/src/wdt.rs
index 8760aa301..330ca98bf 100644
--- a/embassy-nrf/src/wdt.rs
+++ b/embassy-nrf/src/wdt.rs
@@ -23,6 +23,30 @@ pub struct Config {
     pub run_during_debug_halt: bool,
 }
 
+impl Config {
+    /// Create a config structure from the current configuration of the WDT
+    /// peripheral.
+    pub fn try_new(_wdt: &peripherals::WDT) -> Option<Self> {
+        let r = unsafe { &*WDT::ptr() };
+
+        #[cfg(not(feature = "_nrf9160"))]
+        let runstatus = r.runstatus.read().runstatus().bit();
+        #[cfg(feature = "_nrf9160")]
+        let runstatus = r.runstatus.read().runstatuswdt().bit();
+
+        if runstatus {
+            let config = r.config.read();
+            Some(Self {
+                timeout_ticks: r.crv.read().bits(),
+                run_during_sleep: config.sleep().bit(),
+                run_during_debug_halt: config.halt().bit(),
+            })
+        } else {
+            None
+        }
+    }
+}
+
 impl Default for Config {
     fn default() -> Self {
         Self {
diff --git a/examples/boot/application/nrf/src/bin/a.rs b/examples/boot/application/nrf/src/bin/a.rs
index 7a404a914..83191f388 100644
--- a/examples/boot/application/nrf/src/bin/a.rs
+++ b/examples/boot/application/nrf/src/bin/a.rs
@@ -8,6 +8,7 @@ use embassy_embedded_hal::adapter::BlockingAsync;
 use embassy_executor::Spawner;
 use embassy_nrf::gpio::{Input, Level, Output, OutputDrive, Pull};
 use embassy_nrf::nvmc::Nvmc;
+use embassy_nrf::wdt::{self, Watchdog};
 use panic_reset as _;
 
 static APP_B: &[u8] = include_bytes!("../../b.bin");
@@ -20,6 +21,23 @@ async fn main(_spawner: Spawner) {
     //let mut led = Output::new(p.P1_10, Level::Low, OutputDrive::Standard);
     //let mut button = Input::new(p.P1_02, Pull::Up);
 
+    // The following code block illustrates how to obtain a watchdog that is configured
+    // as per the existing watchdog. Ordinarily, we'd use the handle returned to "pet" the
+    // watchdog periodically. If we don't, and we're not going to for this example, then
+    // the watchdog will cause the device to reset as per its configured timeout in the bootloader.
+    // This helps is avoid a situation where new firmware might be bad and block our executor.
+    // If firmware is bad in this way then the bootloader will revert to any previous version.
+    let wdt_config = wdt::Config::try_new(&p.WDT).unwrap();
+    let (_wdt, [_wdt_handle]) = match Watchdog::try_new(p.WDT, wdt_config) {
+        Ok(x) => x,
+        Err(_) => {
+            // Watchdog already active with the wrong number of handles, waiting for it to timeout...
+            loop {
+                cortex_m::asm::wfe();
+            }
+        }
+    };
+
     let nvmc = Nvmc::new(p.NVMC);
     let mut nvmc = BlockingAsync::new(nvmc);