diff --git a/embassy-stm32/src/can/bxcan/registers.rs b/embassy-stm32/src/can/bxcan/registers.rs
index c5467dfe8..c295b0f50 100644
--- a/embassy-stm32/src/can/bxcan/registers.rs
+++ b/embassy-stm32/src/can/bxcan/registers.rs
@@ -299,9 +299,9 @@ impl Registers {
         mb.tdtr().write(|w| w.set_dlc(frame.header().len() as u8));
 
         mb.tdlr()
-            .write(|w| w.0 = u32::from_ne_bytes(unwrap!(frame.data()[0..4].try_into())));
+            .write(|w| w.0 = u32::from_ne_bytes(unwrap!(frame.raw_data()[0..4].try_into())));
         mb.tdhr()
-            .write(|w| w.0 = u32::from_ne_bytes(unwrap!(frame.data()[4..8].try_into())));
+            .write(|w| w.0 = u32::from_ne_bytes(unwrap!(frame.raw_data()[4..8].try_into())));
         let id: IdReg = frame.id().into();
         mb.tir().write(|w| {
             w.0 = id.0;
diff --git a/embassy-stm32/src/can/fd/peripheral.rs b/embassy-stm32/src/can/fd/peripheral.rs
index 39c4112ad..4873ee444 100644
--- a/embassy-stm32/src/can/fd/peripheral.rs
+++ b/embassy-stm32/src/can/fd/peripheral.rs
@@ -75,7 +75,7 @@ impl Registers {
         let mailbox = self.tx_buffer_element(bufidx);
         mailbox.reset();
         put_tx_header(mailbox, header);
-        put_tx_data(mailbox, &buffer[..header.len() as usize]);
+        put_tx_data(mailbox, buffer);
 
         // Set <idx as Mailbox> as ready to transmit
         self.regs.txbar().modify(|w| w.set_ar(bufidx, true));
@@ -190,7 +190,7 @@ impl Registers {
                 DataLength::Fdcan(len) => len,
                 DataLength::Classic(len) => len,
             };
-            if len as usize > ClassicData::MAX_DATA_LEN {
+            if len as usize > 8 {
                 return None;
             }
 
diff --git a/embassy-stm32/src/can/frame.rs b/embassy-stm32/src/can/frame.rs
index f621b8bd5..0fbab053b 100644
--- a/embassy-stm32/src/can/frame.rs
+++ b/embassy-stm32/src/can/frame.rs
@@ -104,15 +104,13 @@ pub trait CanHeader: Sized {
 #[derive(Debug, Copy, Clone)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct ClassicData {
-    pub(crate) bytes: [u8; Self::MAX_DATA_LEN],
+    pub(crate) bytes: [u8; 8],
 }
 
 impl ClassicData {
-    pub(crate) const MAX_DATA_LEN: usize = 8;
     /// Creates a data payload from a raw byte slice.
     ///
-    /// Returns `None` if `data` is more than 64 bytes (which is the maximum) or
-    /// cannot be represented with an FDCAN DLC.
+    /// Returns `FrameCreateError` if `data` is more than 8 bytes (which is the maximum).
     pub fn new(data: &[u8]) -> Result<Self, FrameCreateError> {
         if data.len() > 8 {
             return Err(FrameCreateError::InvalidDataLength);
@@ -211,12 +209,17 @@ impl Frame {
 
     /// Get reference to data
     pub fn data(&self) -> &[u8] {
-        &self.data.raw()
+        &self.data.raw()[..self.can_header.len as usize]
+    }
+
+    /// Get reference to underlying 8-byte raw data buffer, some bytes on the tail might be undefined.
+    pub fn raw_data(&self) -> &[u8] {
+        self.data.raw()
     }
 
     /// Get mutable reference to data
     pub fn data_mut(&mut self) -> &mut [u8] {
-        self.data.raw_mut()
+        &mut self.data.raw_mut()[..self.can_header.len as usize]
     }
 
     /// Get priority of frame
@@ -260,7 +263,7 @@ impl embedded_can::Frame for Frame {
         self.can_header.len as usize
     }
     fn data(&self) -> &[u8] {
-        &self.data.raw()
+        &self.data()
     }
 }
 
@@ -405,12 +408,12 @@ impl FdFrame {
 
     /// Get reference to data
     pub fn data(&self) -> &[u8] {
-        &self.data.raw()
+        &self.data.raw()[..self.can_header.len as usize]
     }
 
     /// Get mutable reference to data
     pub fn data_mut(&mut self) -> &mut [u8] {
-        self.data.raw_mut()
+        &mut self.data.raw_mut()[..self.can_header.len as usize]
     }
 }
 
@@ -448,7 +451,7 @@ impl embedded_can::Frame for FdFrame {
         self.can_header.len as usize
     }
     fn data(&self) -> &[u8] {
-        &self.data.raw()
+        &self.data()
     }
 }
 
diff --git a/embassy-stm32/src/opamp.rs b/embassy-stm32/src/opamp.rs
index a76389495..b368df6c3 100644
--- a/embassy-stm32/src/opamp.rs
+++ b/embassy-stm32/src/opamp.rs
@@ -422,11 +422,13 @@ impl<'d, T: Instance> OpAmp<'d, T> {
 
             T::regs().csr().modify(|w| match pair {
                 OpAmpDifferentialPair::P => {
-                    defmt::info!("p calibration. offset: {}", mid);
+                    #[cfg(feature = "defmt")]
+                    defmt::debug!("opamp p calibration. offset: {}", mid);
                     w.set_trimoffsetp(mid);
                 }
                 OpAmpDifferentialPair::N => {
-                    defmt::info!("n calibration. offset: {}", mid);
+                    #[cfg(feature = "defmt")]
+                    defmt::debug!("opamp n calibration. offset: {}", mid);
                     w.set_trimoffsetn(mid);
                 }
             });