diff --git a/src/lib.rs b/src/lib.rs
index 1f12937f..95c9d484 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,6 +7,8 @@
 
 use enumflags2::{BitFlag, BitFlags};
 
+pub mod pacext;
+
 pub use embedded_hal as hal;
 pub use embedded_hal_02 as hal_02;
 
diff --git a/src/pacext.rs b/src/pacext.rs
new file mode 100644
index 00000000..33b39106
--- /dev/null
+++ b/src/pacext.rs
@@ -0,0 +1,78 @@
+use stm32f4::{Readable, Reg, RegisterSpec, Resettable, Writable, R, W};
+
+pub mod uart;
+
+macro_rules! wrap_r {
+    (pub trait $TrR:ident {
+        $(fn $f:ident(&self $(, $n:ident: u8)?) -> $fr:path;)*
+    }) => {
+        pub trait $TrR {
+            $(fn $f(&self $(, $n: u8)?) -> $fr;)*
+        }
+        impl<REG: reg::$TrR> $TrR for R<REG> {
+            $(
+                #[inline(always)]
+                fn $f(&self $(, $n: u8)?) -> $fr {
+                    REG::$f(self $(, $n)?)
+                }
+            )*
+        }
+    };
+}
+pub(crate) use wrap_r;
+
+macro_rules! wrap_w {
+    (pub trait $TrR:ident {
+        $(fn $f:ident(&mut self $(, $n:ident: u8)?) -> $fr:path;)*
+    }) => {
+        pub trait $TrR<REG: reg::$TrR> {
+            $(fn $f(&mut self $(, $n: u8)?) -> $fr;)*
+        }
+
+        impl<REG: reg::$TrR> $TrR<REG> for W<REG> {
+            $(
+                #[inline(always)]
+                fn $f(&mut self $(, $n: u8)?) -> $fr {
+                    REG::$f(self $(, $n)?)
+                }
+            )*
+        }
+    };
+}
+pub(crate) use wrap_w;
+
+macro_rules! impl_reg {
+    ($($r:ident $(: $n:ident)?  -> &$rty:path;)*) => {
+        $(
+            #[inline(always)]
+            fn $r(&self $(, $n: usize)?) -> &$rty {
+                self.$r($($n)?)
+            }
+        )*
+    };
+}
+pub(crate) use impl_reg;
+
+macro_rules! impl_read {
+    ($($f:ident $(: $n:ident)? -> $fty:path;)*) => {
+        $(
+            #[inline(always)]
+            fn $f(r: &R<Self> $(, $n: u8)?) -> $fty {
+                r.$f($($n)?)
+            }
+        )*
+    };
+}
+pub(crate) use impl_read;
+
+macro_rules! impl_write {
+    ($($f:ident $(: $n:ident)? -> $fty:path;)*) => {
+        $(
+            #[inline(always)]
+            fn $f(w: &mut W<Self> $(, $n: u8)?) -> $fty {
+                w.$f($($n)?)
+            }
+        )*
+    };
+}
+pub(crate) use impl_write;
diff --git a/src/serial/ext.rs b/src/pacext/uart.rs
similarity index 82%
rename from src/serial/ext.rs
rename to src/pacext/uart.rs
index 848c1a68..d231e22f 100644
--- a/src/serial/ext.rs
+++ b/src/pacext/uart.rs
@@ -2,12 +2,12 @@
 
 use crate::{sealed, Sealed};
 
+use super::*;
 #[cfg(feature = "uart4")]
 use crate::pac::uart4;
 use crate::pac::usart1;
-use stm32f4::{Readable, Reg, RegisterSpec, Resettable, Writable, R, W};
 
-pub trait UartExt: Sealed {
+pub trait UartRB: Sealed {
     fn cr1(&self) -> &usart1::CR1;
     fn dr(&self) -> &usart1::DR;
     fn brr(&self) -> &usart1::BRR;
@@ -21,43 +21,6 @@ pub trait UartExt: Sealed {
     fn gtpr(&self) -> &Reg<Self::GTPRrs>;
 }
 
-macro_rules! wrap_r {
-    (pub trait $TrR:ident {
-        $(fn $f:ident(&self $(, $n:ident: u8)?) -> $fr:path;)*
-    }) => {
-        pub trait $TrR {
-            $(fn $f(&self $(, $n: u8)?) -> $fr;)*
-        }
-        impl<REG: reg::$TrR> $TrR for R<REG> {
-            $(
-                #[inline(always)]
-                fn $f(&self $(, $n: u8)?) -> $fr {
-                    REG::$f(self $(, $n)?)
-                }
-            )*
-        }
-    };
-}
-
-macro_rules! wrap_w {
-    (pub trait $TrR:ident {
-        $(fn $f:ident(&mut self $(, $n:ident: u8)?) -> $fr:path;)*
-    }) => {
-        pub trait $TrR<REG: reg::$TrR> {
-            $(fn $f(&mut self $(, $n: u8)?) -> $fr;)*
-        }
-
-        impl<REG: reg::$TrR> $TrR<REG> for W<REG> {
-            $(
-                #[inline(always)]
-                fn $f(&mut self $(, $n: u8)?) -> $fr {
-                    REG::$f(self $(, $n)?)
-                }
-            )*
-        }
-    };
-}
-
 wrap_r! {
     pub trait SrR {
         fn pe(&self) -> usart1::sr::PE_R;
@@ -190,42 +153,10 @@ mod reg {
     }
 }
 
-macro_rules! impl_reg {
-    ($($r:ident -> &$rty:path;)*) => {
-        $(
-            #[inline(always)]
-            fn $r(&self) -> &$rty {
-                self.$r()
-            }
-        )*
-    };
-}
-
-macro_rules! impl_read {
-    ($($f:ident $(: $n:ident)? -> $fty:path;)*) => {
-        $(
-            #[inline(always)]
-            fn $f(r: &R<Self> $(, $n: u8)?) -> $fty {
-                r.$f($($n)?)
-            }
-        )*
-    };
-}
-macro_rules! impl_write {
-    ($($f:ident $(: $n:ident)? -> $fty:path;)*) => {
-        $(
-            #[inline(always)]
-            fn $f(w: &mut W<Self> $(, $n: u8)?) -> $fty {
-                w.$f($($n)?)
-            }
-        )*
-    };
-}
-
 macro_rules! impl_ext {
     ($(#[$attr:meta])* $uart:ident) => {
         impl Sealed for $uart::RegisterBlock {}
-        impl UartExt for $uart::RegisterBlock {
+        impl UartRB for $uart::RegisterBlock {
             type SRrs = $uart::sr::SRrs;
             type CR2rs = $uart::cr2::CR2rs;
             type CR3rs = $uart::cr3::CR3rs;
diff --git a/src/serial.rs b/src/serial.rs
index d3b3f9a5..06256733 100644
--- a/src/serial.rs
+++ b/src/serial.rs
@@ -18,8 +18,7 @@ use core::fmt;
 use core::marker::PhantomData;
 use enumflags2::BitFlags;
 
-pub mod ext;
-use ext::UartExt;
+use crate::pacext::uart::UartRB;
 mod hal_02;
 mod hal_1;
 
diff --git a/src/serial/uart_impls.rs b/src/serial/uart_impls.rs
index 9e7cc23e..34109cf9 100644
--- a/src/serial/uart_impls.rs
+++ b/src/serial/uart_impls.rs
@@ -1,7 +1,9 @@
-use super::{config, config::IrdaMode, ext::*, CFlag, Error, Event, Flag};
+use crate::pacext::uart::{Cr3W, SrR, UartRB};
+
+use super::{config, config::IrdaMode, CFlag, Error, Event, Flag};
 use enumflags2::BitFlags;
 
-pub trait RegisterBlockImpl: UartExt {
+pub trait RegisterBlockImpl: UartRB {
     const IRDA: bool;
     fn configure_irda(&self, irda: IrdaMode, pclk_freq: u32);
     fn set_stopbits(&self, bits: config::StopBits);