diff --git a/flake.nix b/flake.nix
index a45cc17..5c96c60 100644
--- a/flake.nix
+++ b/flake.nix
@@ -50,6 +50,8 @@
 	arm-none-eabi-gcc --version | head -n1
         echo "cargo build --release --target thumbv8m.main-none-eabihf"
         echo "cargo flash --release --chip STM32U575ZI"
+	echo "export DEFMT_LOG=info"
+	echo "cargo run --bin main"
 	echo "probe-rs run --chip STM32U575ZITxQ target/thumbv8m.main-none-eabihf/release/main"
       '';
     };
diff --git a/hal_rng/Cargo.lock b/hal_rng/Cargo.lock
index 0da36eb..dfd24ee 100644
--- a/hal_rng/Cargo.lock
+++ b/hal_rng/Cargo.lock
@@ -178,6 +178,15 @@ dependencies = [
  "syn 2.0.107",
 ]
 
+[[package]]
+name = "defmt"
+version = "0.3.100"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0963443817029b2024136fc4dd07a5107eb8f977eaf18fcd1fdeb11306b64ad"
+dependencies = [
+ "defmt 1.0.1",
+]
+
 [[package]]
 name = "defmt"
 version = "1.0.1"
@@ -217,7 +226,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "93d5a25c99d89c40f5676bec8cefe0614f17f0f40e916f98e345dae941807f9e"
 dependencies = [
  "critical-section",
- "defmt",
+ "defmt 1.0.1",
 ]
 
 [[package]]
@@ -235,6 +244,7 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "554e3e840696f54b4c9afcf28a0f24da431c927f4151040020416e7393d6d0d8"
 dependencies = [
+ "defmt 1.0.1",
  "embassy-futures",
  "embassy-hal-internal",
  "embassy-sync",
@@ -292,6 +302,7 @@ checksum = "95285007a91b619dc9f26ea8f55452aa6c60f7115a4edc05085cd2bd3127cd7a"
 dependencies = [
  "cortex-m",
  "critical-section",
+ "defmt 1.0.1",
  "num-traits",
 ]
 
@@ -300,6 +311,9 @@ name = "embassy-net-driver"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "524eb3c489760508f71360112bca70f6e53173e6fe48fc5f0efd0f5ab217751d"
+dependencies = [
+ "defmt 0.3.100",
+]
 
 [[package]]
 name = "embassy-net-driver-channel"
@@ -326,6 +340,7 @@ dependencies = [
  "cortex-m",
  "cortex-m-rt",
  "critical-section",
+ "defmt 1.0.1",
  "document-features",
  "embassy-embedded-hal",
  "embassy-futures",
@@ -368,6 +383,7 @@ checksum = "73974a3edbd0bd286759b3d483540f0ebef705919a5f56f4fc7709066f71689b"
 dependencies = [
  "cfg-if",
  "critical-section",
+ "defmt 1.0.1",
  "embedded-io-async",
  "futures-core",
  "futures-sink",
@@ -382,6 +398,7 @@ checksum = "f4fa65b9284d974dad7a23bb72835c4ec85c0b540d86af7fc4098c88cff51d65"
 dependencies = [
  "cfg-if",
  "critical-section",
+ "defmt 1.0.1",
  "document-features",
  "embassy-time-driver",
  "embedded-hal 0.2.7",
@@ -431,6 +448,7 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "17119855ccc2d1f7470a39756b12068454ae27a3eabb037d940b5c03d9c77b7a"
 dependencies = [
+ "defmt 1.0.1",
  "embedded-io-async",
 ]
 
@@ -441,6 +459,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "288751f8eaa44a5cf2613f13cee0ca8e06e6638cb96e897e6834702c79084b23"
 dependencies = [
  "critical-section",
+ "defmt 1.0.1",
  "embassy-sync",
  "embassy-usb-driver",
 ]
@@ -517,6 +536,9 @@ name = "embedded-io"
 version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "edd0f118536f44f5ccd48bcb8b111bdc3de888b58c74639dfb034a357d0f206d"
+dependencies = [
+ "defmt 0.3.100",
+]
 
 [[package]]
 name = "embedded-io-async"
@@ -524,6 +546,7 @@ version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3ff09972d4073aa8c299395be75161d582e7629cd663171d62af73c8d50dba3f"
 dependencies = [
+ "defmt 0.3.100",
  "embedded-io",
 ]
 
@@ -599,7 +622,7 @@ version = "0.1.0"
 dependencies = [
  "cortex-m",
  "cortex-m-rt",
- "defmt",
+ "defmt 1.0.1",
  "defmt-rtt",
  "embassy-executor",
  "embassy-futures",
@@ -721,7 +744,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fd402d00b0fb94c5aee000029204a46884b1262e0c443f166d86d2c0747e1a1a"
 dependencies = [
  "cortex-m",
- "defmt",
+ "defmt 1.0.1",
 ]
 
 [[package]]
@@ -892,6 +915,7 @@ checksum = "6fd8ec3a292a0d9fc4798416a61b21da5ae50341b2e7b8d12e662bf305366097"
 dependencies = [
  "cortex-m",
  "cortex-m-rt",
+ "defmt 0.3.100",
 ]
 
 [[package]]
diff --git a/hal_rng/Cargo.toml b/hal_rng/Cargo.toml
index 9078052..7b606c3 100644
--- a/hal_rng/Cargo.toml
+++ b/hal_rng/Cargo.toml
@@ -12,7 +12,7 @@ panic-halt = "1.0.0"
 
 embassy-executor = { version = "0.9.1", features = ["arch-cortex-m", "executor-thread"] }
 embassy-futures = "0.1.2"
-embassy-stm32 = { version = "0.4.0", features = ["unstable-pac", "stm32u575zi", "time-driver-any", "memory-x"] }
+embassy-stm32 = { version = "0.4.0", features = ["unstable-pac", "stm32u575zi", "time-driver-any", "memory-x", "defmt"] }
 embassy-sync = "0.7.2"
 embassy-time = { version = "0.5.0", features = ["tick-hz-32_768"] }
 embassy-usb = "0.5.1"
diff --git a/hal_rng/src/bin/main.rs b/hal_rng/src/bin/main.rs
index f1baf52..df31b1d 100644
--- a/hal_rng/src/bin/main.rs
+++ b/hal_rng/src/bin/main.rs
@@ -3,10 +3,11 @@
 #![no_std]
 #![no_main]
 
+use defmt::*;
 use embassy_executor::Spawner;
 use embassy_stm32::rng::Rng;
 use embassy_stm32::{bind_interrupts, peripherals, rng};
-use panic_probe as _;
+use {defmt_rtt as _, panic_probe as _};
 
 bind_interrupts!(struct Irqs {
     RNG => rng::InterruptHandler<peripherals::RNG>;
@@ -16,7 +17,11 @@ bind_interrupts!(struct Irqs {
 async fn main(_spawner: Spawner) {
     let p = embassy_stm32::init(Default::default());
 
+    info!("Hello World!");
+
     let mut rng = Rng::new(p.RNG, Irqs);
 
     let mut buf = [0u8; 16];
+    unwrap!(rng.async_fill_bytes(&mut buf).await);
+    info!("random bytes: {:02x}", buf);
 }
diff --git a/hal_rng/src/lib.rs b/hal_rng/src/lib.rs
new file mode 100644
index 0000000..0c9ac1a
--- /dev/null
+++ b/hal_rng/src/lib.rs
@@ -0,0 +1 @@
+#![no_std]