diff --git a/src/cpld.rs b/src/cpld.rs
index 0429693..3f00e5a 100644
--- a/src/cpld.rs
+++ b/src/cpld.rs
@@ -49,6 +49,11 @@ where
 
     pub(crate) fn issue_io_update(&mut self) -> Result<(), Error<E>> {
         self.io_update.set_high().map_err(|_| Error::IOUpdateError)?;
+        // I/O Update minimum pulse width: 1 SYNC_CLK cycle
+        // 1 SYNC_CLK cycle = 4 REF_CLK cycle, where f_ref_clk is at least 3.2 MHz
+        // Therefore the maximum required pulse length is 1.25 us,
+        // equivalent to 500 cycles with STM32 sysclk at 400 MHz, longer delay is provided.
+        cortex_m::asm::delay(1_000);
         self.io_update.set_low().map_err(|_| Error::IOUpdateError)
     }
 }
diff --git a/src/dds.rs b/src/dds.rs
index 550b039..1b49472 100644
--- a/src/dds.rs
+++ b/src/dds.rs
@@ -411,7 +411,7 @@ where
                        (profile_content[3] as u64);
         let phase: f64 = ((pow as f64)/(((1_u64) << 16) as f64))*360.0;
 
-        let asf: u64 = (profile_content[0] as u64) <<  8 |
+        let asf: u64 = ((profile_content[0] & 0x3F) as u64) <<  8 |
                        (profile_content[1] as u64);
         let amplitude: f64 = (asf as f64)/(((1_u64) << 14) as f64);
 
diff --git a/src/logger.rs b/src/logger.rs
index 76e1784..b277fe9 100644
--- a/src/logger.rs
+++ b/src/logger.rs
@@ -64,7 +64,7 @@ use cortex_m_log::{
 
 lazy_static! {
     static ref LOGGER: Logger<ItmSync<InterruptFree>> = Logger {
-        level: LevelFilter::Trace,
+        level: LevelFilter::Info,
         inner: unsafe {
             InterruptSync::new(
                 ItmDest::new(cortex_m::Peripherals::steal().ITM)
diff --git a/src/urukul.rs b/src/urukul.rs
index 101d6b1..9ca3cdf 100644
--- a/src/urukul.rs
+++ b/src/urukul.rs
@@ -340,18 +340,7 @@ where
     }
 
     pub fn set_channel_sys_clk(&mut self, channel: u8, f_sys_clk: f64) -> Result<(), Error<E>> {
-        loop {
-            if let Err(e) = self.dds[usize::from(channel)].set_sys_clk_frequency(f_sys_clk).map(|_| ()) {
-                if e.is_wait_retry() {
-                    cortex_m::asm::delay(400_000);
-                } else {
-                    return Err(e);
-                }
-            } else {
-                break;
-            }
-        }
-        Ok(())
+        self.dds[usize::from(channel)].set_sys_clk_frequency(f_sys_clk)
     }
 
     pub fn get_channel_sys_clk(&mut self, channel: u8) -> Result<f64, Error<E>> {