fix: avoid hang if calling now() before syscounter is enabled

If the time driver now() is called before the syscounter is enabled on nrf54,
it would hang. The fix checks if syscounter is enabled, and returns 0
if not.

2 files changed, 6 insertions, 0 deletions

diff --git a/embassy-nrf/CHANGELOG.md b/embassy-nrf/CHANGELOG.md
index 0d7bfb5f0..921835417 100644
--- a/embassy-nrf/CHANGELOG.md
+++ b/embassy-nrf/CHANGELOG.md
@@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 <!-- next-header -->
 ## Unreleased - ReleaseDate
 
+- bugfix: avoid hang if calling now() before syscounter is enabled on nrf54
+
 ## 0.9.0 - 2025-12-15
 
 - changed: apply trimming values from FICR.TRIMCNF on nrf53/54l
diff --git a/embassy-nrf/src/time_driver.rs b/embassy-nrf/src/time_driver.rs
index 35f65bd64..21d94cc30 100644
--- a/embassy-nrf/src/time_driver.rs
+++ b/embassy-nrf/src/time_driver.rs
@@ -79,6 +79,10 @@ fn calc_now(period: u32, counter: u32) -> u64 {
 #[cfg(feature = "_grtc")]
 fn syscounter() -> u64 {
     let r = rtc();
+    if !r.mode().read().syscounteren() {
+        return 0;
+    }
+
     r.syscounter(0).active().write(|w| w.set_active(true));
     loop {
         let countl: u32 = r.syscounter(0).syscounterl().read();