From e527892d89ff14b6af4aad778945c4675423fa77 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 16:29:22 -0700
Subject: [PATCH 01/16] Start work on CRC_v1

---
 embassy-stm32/src/crc/mod.rs |  4 ++++
 embassy-stm32/src/crc/v1.rs  | 21 +++++++++++++++++++++
 embassy-stm32/src/crc/v2.rs  |  0
 embassy-stm32/src/crc/v3.rs  |  0
 embassy-stm32/src/lib.rs     |  2 ++
 5 files changed, 27 insertions(+)
 create mode 100644 embassy-stm32/src/crc/mod.rs
 create mode 100644 embassy-stm32/src/crc/v1.rs
 create mode 100644 embassy-stm32/src/crc/v2.rs
 create mode 100644 embassy-stm32/src/crc/v3.rs

diff --git a/embassy-stm32/src/crc/mod.rs b/embassy-stm32/src/crc/mod.rs
new file mode 100644
index 000000000..79e00be73
--- /dev/null
+++ b/embassy-stm32/src/crc/mod.rs
@@ -0,0 +1,4 @@
+#[cfg_attr(crc_v1, path = "v1.rs")]
+#[cfg_attr(crc_v2, path = "v2.rs")]
+#[cfg_attr(crc_v3, path = "v3.rs")]
+mod _version;
\ No newline at end of file
diff --git a/embassy-stm32/src/crc/v1.rs b/embassy-stm32/src/crc/v1.rs
new file mode 100644
index 000000000..4fc23fe39
--- /dev/null
+++ b/embassy-stm32/src/crc/v1.rs
@@ -0,0 +1,21 @@
+use crate::pac::{CRC as PAC_CRC, RCC};
+use crate::peripherals::CRC;
+use crate::rcc::sealed::RccPeripheral;
+
+pub struct Crc {
+    _peripheral: CRC
+}
+
+impl Crc{
+    pub fn new(peripheral: CRC) -> Self{
+        // enable CRC clock in RCC.
+        CRC::enable();
+        // Reset CRC to default values.
+        CRC::reset();
+        Self { _peripheral: peripheral}
+    }
+
+    pub fn reset() {
+        unsafe { PAC_CRC.cr().modify(|w| w.set_reset(true)) };
+    }
+}
\ No newline at end of file
diff --git a/embassy-stm32/src/crc/v2.rs b/embassy-stm32/src/crc/v2.rs
new file mode 100644
index 000000000..e69de29bb
diff --git a/embassy-stm32/src/crc/v3.rs b/embassy-stm32/src/crc/v3.rs
new file mode 100644
index 000000000..e69de29bb
diff --git a/embassy-stm32/src/lib.rs b/embassy-stm32/src/lib.rs
index 073e79f2f..711c29971 100644
--- a/embassy-stm32/src/lib.rs
+++ b/embassy-stm32/src/lib.rs
@@ -49,6 +49,8 @@ pub mod sdmmc;
 pub mod spi;
 #[cfg(usart)]
 pub mod usart;
+#[cfg(crc)]
+pub mod crc;
 
 #[cfg(feature = "subghz")]
 pub mod subghz;

From e18a27eea2aca005f01fdde72162b14e976f358a Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 16:46:17 -0700
Subject: [PATCH 02/16] First pass at CRC_V1

---
 embassy-stm32/src/crc/mod.rs |  2 +-
 embassy-stm32/src/crc/v1.rs  | 47 ++++++++++++++++++++++++++++++------
 embassy-stm32/src/crc/v2.rs  |  1 +
 embassy-stm32/src/crc/v3.rs  |  1 +
 embassy-stm32/src/lib.rs     |  4 +--
 5 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/embassy-stm32/src/crc/mod.rs b/embassy-stm32/src/crc/mod.rs
index 79e00be73..02fa1278b 100644
--- a/embassy-stm32/src/crc/mod.rs
+++ b/embassy-stm32/src/crc/mod.rs
@@ -1,4 +1,4 @@
 #[cfg_attr(crc_v1, path = "v1.rs")]
 #[cfg_attr(crc_v2, path = "v2.rs")]
 #[cfg_attr(crc_v3, path = "v3.rs")]
-mod _version;
\ No newline at end of file
+mod _version;
diff --git a/embassy-stm32/src/crc/v1.rs b/embassy-stm32/src/crc/v1.rs
index 4fc23fe39..52ccca660 100644
--- a/embassy-stm32/src/crc/v1.rs
+++ b/embassy-stm32/src/crc/v1.rs
@@ -1,21 +1,54 @@
-use crate::pac::{CRC as PAC_CRC, RCC};
+use crate::pac::CRC as PAC_CRC;
 use crate::peripherals::CRC;
 use crate::rcc::sealed::RccPeripheral;
 
 pub struct Crc {
-    _peripheral: CRC
+    _peripheral: CRC,
 }
 
-impl Crc{
-    pub fn new(peripheral: CRC) -> Self{
+impl Crc {
+    /// Instantiates the CRC32 peripheral and initializes it to default values.
+    pub fn new(peripheral: CRC) -> Self {
+        // Note: enable and reset come from RccPeripheral.
         // enable CRC clock in RCC.
         CRC::enable();
         // Reset CRC to default values.
         CRC::reset();
-        Self { _peripheral: peripheral}
+        let mut instance = Self {
+            _peripheral: peripheral,
+        };
+        instance.init();
+        instance
     }
 
-    pub fn reset() {
+    /// Resets the CRC unit to default value (0xFFFF_FFFF)
+    pub fn init(&mut self) {
         unsafe { PAC_CRC.cr().modify(|w| w.set_reset(true)) };
     }
-}
\ No newline at end of file
+
+    /// Feeds a word to the peripheral and returns the current CRC value
+    pub fn feed_word(&mut self, word: u32) -> u32 {
+        // write a single byte to the device, and return the result
+        unsafe {
+            PAC_CRC.dr().write_value(word);
+            PAC_CRC.dr().read()
+        }
+    }
+    /// Feed a slice of words to the peripheral and return the result.
+    pub fn feed_words(&mut self, words: &[u32]) -> u32 {
+        for word in words {
+            unsafe {
+                PAC_CRC.dr().write_value(*word);
+            }
+        }
+
+        unsafe { PAC_CRC.dr().read() }
+    }
+
+    /// Reclaims the CRC peripheral.
+    pub fn release(self) -> CRC {
+        CRC::disable();
+
+        self._peripheral
+    }
+}
diff --git a/embassy-stm32/src/crc/v2.rs b/embassy-stm32/src/crc/v2.rs
index e69de29bb..8b1378917 100644
--- a/embassy-stm32/src/crc/v2.rs
+++ b/embassy-stm32/src/crc/v2.rs
@@ -0,0 +1 @@
+
diff --git a/embassy-stm32/src/crc/v3.rs b/embassy-stm32/src/crc/v3.rs
index e69de29bb..8b1378917 100644
--- a/embassy-stm32/src/crc/v3.rs
+++ b/embassy-stm32/src/crc/v3.rs
@@ -0,0 +1 @@
+
diff --git a/embassy-stm32/src/lib.rs b/embassy-stm32/src/lib.rs
index 711c29971..424b1c994 100644
--- a/embassy-stm32/src/lib.rs
+++ b/embassy-stm32/src/lib.rs
@@ -39,6 +39,8 @@ pub mod exti;
 #[cfg(i2c)]
 pub mod i2c;
 
+#[cfg(crc)]
+pub mod crc;
 #[cfg(pwr)]
 pub mod pwr;
 #[cfg(rng)]
@@ -49,8 +51,6 @@ pub mod sdmmc;
 pub mod spi;
 #[cfg(usart)]
 pub mod usart;
-#[cfg(crc)]
-pub mod crc;
 
 #[cfg(feature = "subghz")]
 pub mod subghz;

From 4760afd9f44738603fee36f49a9e0e29bf784889 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 16:53:32 -0700
Subject: [PATCH 03/16] Update stm32-data

---
 stm32-data | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stm32-data b/stm32-data
index 8cdca8ad5..ded0ac053 160000
--- a/stm32-data
+++ b/stm32-data
@@ -1 +1 @@
-Subproject commit 8cdca8ad5b65d9a63c5198370ea337ddd03f32b1
+Subproject commit ded0ac053d88db503bc395d8dbdbf6e7550b6859

From 24dea91f5abdd4029c7c912dd01d92313da58df3 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 17:24:48 -0700
Subject: [PATCH 04/16] Fix interface changes

---
 embassy-stm32/src/crc/v1.rs | 6 +++---
 stm32-data                  | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/embassy-stm32/src/crc/v1.rs b/embassy-stm32/src/crc/v1.rs
index 52ccca660..b95df8838 100644
--- a/embassy-stm32/src/crc/v1.rs
+++ b/embassy-stm32/src/crc/v1.rs
@@ -1,4 +1,4 @@
-use crate::pac::CRC as PAC_CRC;
+use crate::pac::{CRC as PAC_CRC};
 use crate::peripherals::CRC;
 use crate::rcc::sealed::RccPeripheral;
 
@@ -23,7 +23,7 @@ impl Crc {
 
     /// Resets the CRC unit to default value (0xFFFF_FFFF)
     pub fn init(&mut self) {
-        unsafe { PAC_CRC.cr().modify(|w| w.set_reset(true)) };
+        unsafe { PAC_CRC.cr().write(|w| w.set_reset(true)) };
     }
 
     /// Feeds a word to the peripheral and returns the current CRC value
@@ -38,7 +38,7 @@ impl Crc {
     pub fn feed_words(&mut self, words: &[u32]) -> u32 {
         for word in words {
             unsafe {
-                PAC_CRC.dr().write_value(*word);
+                PAC_CRC.dr().write_value(*word)
             }
         }
 
diff --git a/stm32-data b/stm32-data
index ded0ac053..9e8e34786 160000
--- a/stm32-data
+++ b/stm32-data
@@ -1 +1 @@
-Subproject commit ded0ac053d88db503bc395d8dbdbf6e7550b6859
+Subproject commit 9e8e34786222b76a7d1bbbc1baf14cd3b33cd2d7

From c892289b2c11b0c707ef2578583a249b05f779b2 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 17:26:33 -0700
Subject: [PATCH 05/16] Actually export CRC

---
 embassy-stm32/src/crc/mod.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/embassy-stm32/src/crc/mod.rs b/embassy-stm32/src/crc/mod.rs
index 02fa1278b..d8de4bd09 100644
--- a/embassy-stm32/src/crc/mod.rs
+++ b/embassy-stm32/src/crc/mod.rs
@@ -2,3 +2,5 @@
 #[cfg_attr(crc_v2, path = "v2.rs")]
 #[cfg_attr(crc_v3, path = "v3.rs")]
 mod _version;
+
+pub use _version::Crc;

From 7899d733590ad373e0dea215d0b084f32412a816 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 17:28:58 -0700
Subject: [PATCH 06/16] Expose read so the value can be obtained without a
 write.

---
 embassy-stm32/src/crc/v1.rs | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/embassy-stm32/src/crc/v1.rs b/embassy-stm32/src/crc/v1.rs
index b95df8838..09c8eecb6 100644
--- a/embassy-stm32/src/crc/v1.rs
+++ b/embassy-stm32/src/crc/v1.rs
@@ -1,4 +1,4 @@
-use crate::pac::{CRC as PAC_CRC};
+use crate::pac::CRC as PAC_CRC;
 use crate::peripherals::CRC;
 use crate::rcc::sealed::RccPeripheral;
 
@@ -31,17 +31,18 @@ impl Crc {
         // write a single byte to the device, and return the result
         unsafe {
             PAC_CRC.dr().write_value(word);
-            PAC_CRC.dr().read()
         }
+        self.read()
     }
     /// Feed a slice of words to the peripheral and return the result.
     pub fn feed_words(&mut self, words: &[u32]) -> u32 {
         for word in words {
-            unsafe {
-                PAC_CRC.dr().write_value(*word)
-            }
+            unsafe { PAC_CRC.dr().write_value(*word) }
         }
 
+        self.read()
+    }
+    pub fn read(&self) -> u32 {
         unsafe { PAC_CRC.dr().read() }
     }
 

From afef19d813d7301631e98f432621ceaa963d253e Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 18:26:20 -0700
Subject: [PATCH 07/16] Start work towards CRC_V2

---
 embassy-stm32/src/crc/mod.rs |  9 ++--
 embassy-stm32/src/crc/v2.rs  | 86 ++++++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+), 3 deletions(-)

diff --git a/embassy-stm32/src/crc/mod.rs b/embassy-stm32/src/crc/mod.rs
index d8de4bd09..42f131af7 100644
--- a/embassy-stm32/src/crc/mod.rs
+++ b/embassy-stm32/src/crc/mod.rs
@@ -1,6 +1,9 @@
-#[cfg_attr(crc_v1, path = "v1.rs")]
-#[cfg_attr(crc_v2, path = "v2.rs")]
+use crate::peripherals::CRC;
+
+
+#[cfg_attr(crc_v2, path = "v1.rs")]
+#[cfg_attr(crc_v1, path = "v2.rs")]
 #[cfg_attr(crc_v3, path = "v3.rs")]
 mod _version;
 
-pub use _version::Crc;
+pub use _version::Crc;
\ No newline at end of file
diff --git a/embassy-stm32/src/crc/v2.rs b/embassy-stm32/src/crc/v2.rs
index 8b1378917..523bad10f 100644
--- a/embassy-stm32/src/crc/v2.rs
+++ b/embassy-stm32/src/crc/v2.rs
@@ -1 +1,87 @@
+use crate::pac::CRC as PAC_CRC;
+use crate::pac::crc::vals;
+use crate::peripherals::CRC;
+use crate::rcc::sealed::RccPeripheral;
 
+pub struct Crc {
+    _peripheral: CRC,
+    _config: CrcConfig,
+}
+
+pub enum CrcConfigError {
+    InvalidPolynomial
+}
+
+pub struct CrcConfig {
+    reverse_in: CrcInputReverseConfig,
+    reverse_out: bool,
+    poly_size: PolySize,
+    crc_init_value: u32,
+    crc_poly: u32,
+}
+
+pub enum CrcInputReverseConfig {
+    None,
+    Byte,
+    Halfword,
+    Word,
+}
+
+impl CrcConfig {
+    pub fn new(reverse_in: CrcInputReverseConfig, reverse_out: bool, poly_size: PolySize, crc_init_value: u32, crc_poly: u32) -> Result<Self, CrcConfigError> {
+        // As Per RM0091 (DocID018940 Rev 9), Even polynomials are not supported.
+        if crc_poly % 2 == 0 {
+            Err(CrcConfigError::InvalidPolynomial)
+        } else {
+            Ok(CrcConfig { reverse_in, reverse_out, poly_size, crc_init_value, crc_poly })
+        }
+    }
+}
+
+pub enum PolySize {
+    Width7,
+    Width8,
+    Width16,
+    Width32,
+}
+
+impl Crc {
+    /// Instantiates the CRC32 peripheral and initializes it to default values.
+    pub fn new(peripheral: CRC, init_value: u32, config: CrcConfig) -> Self {
+        // Note: enable and reset come from RccPeripheral.
+        // enable CRC clock in RCC.
+        CRC::enable();
+        // Reset CRC to default values.
+        CRC::reset();
+        let mut instance = Self {
+            _peripheral: peripheral,
+        };
+        instance.init();
+        instance
+    }
+
+    // Configure device settings
+    fn configure_revout(&mut self) {
+        unsafe {
+            PAC_CRC.cr().modify(|w| {w.set_rev_out(
+                match self._config.reverse_out {
+                    true => {vals::RevOut::REVERSED}
+                    false => {vals::RevOut::NORMAL}
+                }
+            )})
+        }
+    }
+
+    fn configure_revin(&mut self) {
+        unsafe {
+            PAC_CRC.cr().modify(|w| {w.set_rev_in(
+                match self._config.reverse_in {
+                    CrcInputReverseConfig::None => {vals::RevIn::NORMAL}
+                    CrcInputReverseConfig::Byte => {vals::RevIn::BYTE}
+                    CrcInputReverseConfig::Halfword => {vals::RevIn::HALFWORD}
+                    CrcInputReverseConfig::Word => {vals::RevIn::WORD}
+                }
+            )})
+        }
+    }
+}
\ No newline at end of file

From 8fac444c4e54cc13f514a23e36da737d70cf7eea Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 18:39:55 -0700
Subject: [PATCH 08/16] Flesh out v2 config writes

---
 embassy-stm32/src/crc/v2.rs | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/embassy-stm32/src/crc/v2.rs b/embassy-stm32/src/crc/v2.rs
index 523bad10f..db4a3699a 100644
--- a/embassy-stm32/src/crc/v2.rs
+++ b/embassy-stm32/src/crc/v2.rs
@@ -55,9 +55,11 @@ impl Crc {
         CRC::reset();
         let mut instance = Self {
             _peripheral: peripheral,
+            _config: config
         };
-        instance.init();
-        instance
+        unimplemented!();
+        // instance.init();
+        // instance
     }
 
     // Configure device settings
@@ -84,4 +86,28 @@ impl Crc {
             )})
         }
     }
+
+    fn configure_polysize(&mut self) {
+        unsafe {
+            PAC_CRC.cr().modify(|w| {w.set_polysize(
+                match self._config.poly_size {
+                    PolySize::Width7 => {vals::Polysize::POLYSIZE7}
+                    PolySize::Width8 => {vals::Polysize::POLYSIZE8}
+                    PolySize::Width16 => {vals::Polysize::POLYSIZE16}
+                    PolySize::Width32 => {vals::Polysize::POLYSIZE32}
+                }
+            )})
+        }
+    }
+
+    pub fn reset(&mut self) {
+        unsafe { PAC_CRC.cr().modify(|w| w.set_reset(true)); }
+    }
+
+    fn set_crc_init(&mut self, value: u32) {
+        unsafe {
+            PAC_CRC.init().write_value(value)
+        }
+    }
+
 }
\ No newline at end of file

From f9ff5336d4c78e571c755e63ef360393e29a1f51 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 18:46:19 -0700
Subject: [PATCH 09/16] Merge all of the crc_v2 configurations into a single
 modify call

---
 embassy-stm32/src/crc/v2.rs | 80 ++++++++++++++++++-------------------
 1 file changed, 38 insertions(+), 42 deletions(-)

diff --git a/embassy-stm32/src/crc/v2.rs b/embassy-stm32/src/crc/v2.rs
index db4a3699a..b21e6c633 100644
--- a/embassy-stm32/src/crc/v2.rs
+++ b/embassy-stm32/src/crc/v2.rs
@@ -55,59 +55,55 @@ impl Crc {
         CRC::reset();
         let mut instance = Self {
             _peripheral: peripheral,
-            _config: config
+            _config: config,
         };
         unimplemented!();
         // instance.init();
         // instance
     }
 
-    // Configure device settings
-    fn configure_revout(&mut self) {
-        unsafe {
-            PAC_CRC.cr().modify(|w| {w.set_rev_out(
-                match self._config.reverse_out {
-                    true => {vals::RevOut::REVERSED}
-                    false => {vals::RevOut::NORMAL}
-                }
-            )})
-        }
-    }
 
-    fn configure_revin(&mut self) {
-        unsafe {
-            PAC_CRC.cr().modify(|w| {w.set_rev_in(
-                match self._config.reverse_in {
-                    CrcInputReverseConfig::None => {vals::RevIn::NORMAL}
-                    CrcInputReverseConfig::Byte => {vals::RevIn::BYTE}
-                    CrcInputReverseConfig::Halfword => {vals::RevIn::HALFWORD}
-                    CrcInputReverseConfig::Word => {vals::RevIn::WORD}
-                }
-            )})
-        }
-    }
-
-    fn configure_polysize(&mut self) {
-        unsafe {
-            PAC_CRC.cr().modify(|w| {w.set_polysize(
-                match self._config.poly_size {
-                    PolySize::Width7 => {vals::Polysize::POLYSIZE7}
-                    PolySize::Width8 => {vals::Polysize::POLYSIZE8}
-                    PolySize::Width16 => {vals::Polysize::POLYSIZE16}
-                    PolySize::Width32 => {vals::Polysize::POLYSIZE32}
-                }
-            )})
-        }
-    }
 
     pub fn reset(&mut self) {
         unsafe { PAC_CRC.cr().modify(|w| w.set_reset(true)); }
     }
 
-    fn set_crc_init(&mut self, value: u32) {
-        unsafe {
-            PAC_CRC.init().write_value(value)
-        }
-    }
 
+    fn reconfigure(&mut self) {
+        unsafe {
+            // Init CRC value
+            PAC_CRC.init().write_value(self._config.crc_init_value);
+
+            PAC_CRC.cr().modify(|w| {
+                // configure reverse output
+                w.set_rev_out(
+                    match self._config.reverse_out {
+                        true => { vals::RevOut::REVERSED }
+                        false => { vals::RevOut::NORMAL }
+                    }
+                );
+                // configure reverse input
+                w.set_rev_in(
+                    match self._config.reverse_in {
+                        CrcInputReverseConfig::None => { vals::RevIn::NORMAL }
+                        CrcInputReverseConfig::Byte => { vals::RevIn::BYTE }
+                        CrcInputReverseConfig::Halfword => { vals::RevIn::HALFWORD }
+                        CrcInputReverseConfig::Word => { vals::RevIn::WORD }
+                    }
+                );
+                // configure the polynomial.
+                w.set_polysize(
+                    match self._config.poly_size {
+                        PolySize::Width7 => { vals::Polysize::POLYSIZE7 }
+                        PolySize::Width8 => { vals::Polysize::POLYSIZE8 }
+                        PolySize::Width16 => { vals::Polysize::POLYSIZE16 }
+                        PolySize::Width32 => { vals::Polysize::POLYSIZE32 }
+                    }
+                )
+
+            })
+        }
+
+        self.reset();
+    }
 }
\ No newline at end of file

From 642b0825a62a7d40c3496c32ac6abd8dce3e55bd Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 19:14:08 -0700
Subject: [PATCH 10/16] V3 is just an extension of V2, merge modules.

---
 embassy-stm32/src/crc/v2.rs | 144 ++++++++++++++++++++++++++----------
 embassy-stm32/src/crc/v3.rs |   1 -
 2 files changed, 106 insertions(+), 39 deletions(-)
 delete mode 100644 embassy-stm32/src/crc/v3.rs

diff --git a/embassy-stm32/src/crc/v2.rs b/embassy-stm32/src/crc/v2.rs
index b21e6c633..3336d3f75 100644
--- a/embassy-stm32/src/crc/v2.rs
+++ b/embassy-stm32/src/crc/v2.rs
@@ -1,5 +1,5 @@
-use crate::pac::CRC as PAC_CRC;
 use crate::pac::crc::vals;
+use crate::pac::CRC as PAC_CRC;
 use crate::peripherals::CRC;
 use crate::rcc::sealed::RccPeripheral;
 
@@ -9,14 +9,16 @@ pub struct Crc {
 }
 
 pub enum CrcConfigError {
-    InvalidPolynomial
+    InvalidPolynomial,
 }
 
 pub struct CrcConfig {
     reverse_in: CrcInputReverseConfig,
     reverse_out: bool,
+    #[cfg(crc_v3)]
     poly_size: PolySize,
     crc_init_value: u32,
+    #[cfg(crc_v3)]
     crc_poly: u32,
 }
 
@@ -28,16 +30,33 @@ pub enum CrcInputReverseConfig {
 }
 
 impl CrcConfig {
-    pub fn new(reverse_in: CrcInputReverseConfig, reverse_out: bool, poly_size: PolySize, crc_init_value: u32, crc_poly: u32) -> Result<Self, CrcConfigError> {
+    pub fn new(
+        reverse_in: CrcInputReverseConfig,
+        reverse_out: bool,
+        #[cfg(crc_v3)]
+        poly_size: PolySize,
+        crc_init_value: u32,
+        #[cfg(crc_v3)]
+        crc_poly: u32,
+    ) -> Result<Self, CrcConfigError> {
         // As Per RM0091 (DocID018940 Rev 9), Even polynomials are not supported.
+        #[cfg(crc_v3)]
         if crc_poly % 2 == 0 {
-            Err(CrcConfigError::InvalidPolynomial)
-        } else {
-            Ok(CrcConfig { reverse_in, reverse_out, poly_size, crc_init_value, crc_poly })
+            return Err(CrcConfigError::InvalidPolynomial);
         }
+        Ok(CrcConfig {
+            reverse_in,
+            reverse_out,
+            #[cfg(crc_v3)]
+            poly_size,
+            crc_init_value,
+            #[cfg(crc_v3)]
+            crc_poly,
+        })
     }
 }
 
+#[cfg(crc_v3)]
 pub enum PolySize {
     Width7,
     Width8,
@@ -47,7 +66,7 @@ pub enum PolySize {
 
 impl Crc {
     /// Instantiates the CRC32 peripheral and initializes it to default values.
-    pub fn new(peripheral: CRC, init_value: u32, config: CrcConfig) -> Self {
+    pub fn new(peripheral: CRC, config: CrcConfig) -> Self {
         // Note: enable and reset come from RccPeripheral.
         // enable CRC clock in RCC.
         CRC::enable();
@@ -57,53 +76,102 @@ impl Crc {
             _peripheral: peripheral,
             _config: config,
         };
-        unimplemented!();
-        // instance.init();
-        // instance
+        CRC::reset();
+        instance.reconfigure();
+        instance.reset();
+        instance
     }
 
-
-
     pub fn reset(&mut self) {
-        unsafe { PAC_CRC.cr().modify(|w| w.set_reset(true)); }
+        unsafe {
+            PAC_CRC.cr().modify(|w| w.set_reset(true));
+        }
     }
 
-
+    /// Reconfigures the CRC peripheral. Doesn't reset.
     fn reconfigure(&mut self) {
         unsafe {
             // Init CRC value
             PAC_CRC.init().write_value(self._config.crc_init_value);
+            #[cfg(crc_v3)]
+                PAC_CRC.pol().write_value(self._config.crc_poly);
 
+            // configure CR components
+            // (reverse I/O, polysize, poly)
             PAC_CRC.cr().modify(|w| {
                 // configure reverse output
-                w.set_rev_out(
-                    match self._config.reverse_out {
-                        true => { vals::RevOut::REVERSED }
-                        false => { vals::RevOut::NORMAL }
-                    }
-                );
+                w.set_rev_out(match self._config.reverse_out {
+                    true => vals::RevOut::REVERSED,
+                    false => vals::RevOut::NORMAL,
+                });
                 // configure reverse input
-                w.set_rev_in(
-                    match self._config.reverse_in {
-                        CrcInputReverseConfig::None => { vals::RevIn::NORMAL }
-                        CrcInputReverseConfig::Byte => { vals::RevIn::BYTE }
-                        CrcInputReverseConfig::Halfword => { vals::RevIn::HALFWORD }
-                        CrcInputReverseConfig::Word => { vals::RevIn::WORD }
-                    }
-                );
+                w.set_rev_in(match self._config.reverse_in {
+                    CrcInputReverseConfig::None => vals::RevIn::NORMAL,
+                    CrcInputReverseConfig::Byte => vals::RevIn::BYTE,
+                    CrcInputReverseConfig::Halfword => vals::RevIn::HALFWORD,
+                    CrcInputReverseConfig::Word => vals::RevIn::WORD,
+                });
                 // configure the polynomial.
-                w.set_polysize(
-                    match self._config.poly_size {
-                        PolySize::Width7 => { vals::Polysize::POLYSIZE7 }
-                        PolySize::Width8 => { vals::Polysize::POLYSIZE8 }
-                        PolySize::Width16 => { vals::Polysize::POLYSIZE16 }
-                        PolySize::Width32 => { vals::Polysize::POLYSIZE32 }
-                    }
-                )
-
+                #[cfg(crc_v3)]
+                    w.set_polysize(match self._config.poly_size {
+                    PolySize::Width7 => vals::Polysize::POLYSIZE7,
+                    PolySize::Width8 => vals::Polysize::POLYSIZE8,
+                    PolySize::Width16 => vals::Polysize::POLYSIZE16,
+                    PolySize::Width32 => vals::Polysize::POLYSIZE32,
+                });
             })
         }
 
         self.reset();
     }
-}
\ No newline at end of file
+
+    /// Feeds a byte into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_byte(&mut self, byte: u8) -> u32 {
+        unsafe {
+            PAC_CRC.dr8().write_value(byte as u32);
+            PAC_CRC.dr().read()
+        }
+    }
+
+    /// Feeds an slice of bytes into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_bytes(&mut self, bytes: &[u8]) -> u32 {
+        for byte in bytes {
+            unsafe { PAC_CRC.dr8().write_value(*byte as u32); }
+        }
+        unsafe {
+            PAC_CRC.dr().read()
+        }
+    }
+    /// Feeds a halfword into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_halfword(&mut self, byte: u16) -> u32 {
+        unsafe {
+            PAC_CRC.dr16().write_value(byte as u32);
+            PAC_CRC.dr().read()
+        }
+    }
+    /// Feeds an slice of halfwords into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_halfwords(&mut self, bytes: &[u16]) -> u32 {
+        for byte in bytes {
+            unsafe { PAC_CRC.dr16().write_value(*byte as u32); }
+        }
+        unsafe {
+            PAC_CRC.dr().read()
+        }
+    }
+    /// Feeds a halfword into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_word(&mut self, byte: u32) -> u32 {
+        unsafe {
+            PAC_CRC.dr().write_value(byte as u32);
+            PAC_CRC.dr().read()
+        }
+    }
+    /// Feeds an slice of halfwords into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_words(&mut self, bytes: &[u32]) -> u32 {
+        for byte in bytes {
+            unsafe { PAC_CRC.dr().write_value(*byte as u32); }
+        }
+        unsafe {
+            PAC_CRC.dr().read()
+        }
+    }
+}
diff --git a/embassy-stm32/src/crc/v3.rs b/embassy-stm32/src/crc/v3.rs
deleted file mode 100644
index 8b1378917..000000000
--- a/embassy-stm32/src/crc/v3.rs
+++ /dev/null
@@ -1 +0,0 @@
-

From e67af514e921b3b28b4c20a88554c4d7cbef7951 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 19:15:54 -0700
Subject: [PATCH 11/16] Fix v2/3 module paths

---
 embassy-stm32/src/crc/mod.rs | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/embassy-stm32/src/crc/mod.rs b/embassy-stm32/src/crc/mod.rs
index 42f131af7..597e7cf3a 100644
--- a/embassy-stm32/src/crc/mod.rs
+++ b/embassy-stm32/src/crc/mod.rs
@@ -1,9 +1,6 @@
-use crate::peripherals::CRC;
-
-
-#[cfg_attr(crc_v2, path = "v1.rs")]
-#[cfg_attr(crc_v1, path = "v2.rs")]
-#[cfg_attr(crc_v3, path = "v3.rs")]
+#[cfg_attr(crc_v2, path = "v2.rs")]
+#[cfg_attr(crc_v1, path = "v1.rs")]
+#[cfg_attr(crc_v3, path = "v2.rs")]
 mod _version;
 
 pub use _version::Crc;
\ No newline at end of file

From 7392e33ad563642453bde20c9d33120af6b7ccbb Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Sun, 26 Sep 2021 19:20:21 -0700
Subject: [PATCH 12/16] cargo fmt

---
 embassy-stm32/src/crc/mod.rs |  2 +-
 embassy-stm32/src/crc/v2.rs  | 34 ++++++++++++++++------------------
 2 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/embassy-stm32/src/crc/mod.rs b/embassy-stm32/src/crc/mod.rs
index 597e7cf3a..70c87ab53 100644
--- a/embassy-stm32/src/crc/mod.rs
+++ b/embassy-stm32/src/crc/mod.rs
@@ -3,4 +3,4 @@
 #[cfg_attr(crc_v3, path = "v2.rs")]
 mod _version;
 
-pub use _version::Crc;
\ No newline at end of file
+pub use _version::Crc;
diff --git a/embassy-stm32/src/crc/v2.rs b/embassy-stm32/src/crc/v2.rs
index 3336d3f75..7705b4285 100644
--- a/embassy-stm32/src/crc/v2.rs
+++ b/embassy-stm32/src/crc/v2.rs
@@ -33,11 +33,9 @@ impl CrcConfig {
     pub fn new(
         reverse_in: CrcInputReverseConfig,
         reverse_out: bool,
-        #[cfg(crc_v3)]
-        poly_size: PolySize,
+        #[cfg(crc_v3)] poly_size: PolySize,
         crc_init_value: u32,
-        #[cfg(crc_v3)]
-        crc_poly: u32,
+        #[cfg(crc_v3)] crc_poly: u32,
     ) -> Result<Self, CrcConfigError> {
         // As Per RM0091 (DocID018940 Rev 9), Even polynomials are not supported.
         #[cfg(crc_v3)]
@@ -94,7 +92,7 @@ impl Crc {
             // Init CRC value
             PAC_CRC.init().write_value(self._config.crc_init_value);
             #[cfg(crc_v3)]
-                PAC_CRC.pol().write_value(self._config.crc_poly);
+            PAC_CRC.pol().write_value(self._config.crc_poly);
 
             // configure CR components
             // (reverse I/O, polysize, poly)
@@ -113,7 +111,7 @@ impl Crc {
                 });
                 // configure the polynomial.
                 #[cfg(crc_v3)]
-                    w.set_polysize(match self._config.poly_size {
+                w.set_polysize(match self._config.poly_size {
                     PolySize::Width7 => vals::Polysize::POLYSIZE7,
                     PolySize::Width8 => vals::Polysize::POLYSIZE8,
                     PolySize::Width16 => vals::Polysize::POLYSIZE16,
@@ -136,11 +134,11 @@ impl Crc {
     /// Feeds an slice of bytes into the CRC peripheral. Returns the computed checksum.
     pub fn feed_bytes(&mut self, bytes: &[u8]) -> u32 {
         for byte in bytes {
-            unsafe { PAC_CRC.dr8().write_value(*byte as u32); }
-        }
-        unsafe {
-            PAC_CRC.dr().read()
+            unsafe {
+                PAC_CRC.dr8().write_value(*byte as u32);
+            }
         }
+        unsafe { PAC_CRC.dr().read() }
     }
     /// Feeds a halfword into the CRC peripheral. Returns the computed checksum.
     pub fn feed_halfword(&mut self, byte: u16) -> u32 {
@@ -152,11 +150,11 @@ impl Crc {
     /// Feeds an slice of halfwords into the CRC peripheral. Returns the computed checksum.
     pub fn feed_halfwords(&mut self, bytes: &[u16]) -> u32 {
         for byte in bytes {
-            unsafe { PAC_CRC.dr16().write_value(*byte as u32); }
-        }
-        unsafe {
-            PAC_CRC.dr().read()
+            unsafe {
+                PAC_CRC.dr16().write_value(*byte as u32);
+            }
         }
+        unsafe { PAC_CRC.dr().read() }
     }
     /// Feeds a halfword into the CRC peripheral. Returns the computed checksum.
     pub fn feed_word(&mut self, byte: u32) -> u32 {
@@ -168,10 +166,10 @@ impl Crc {
     /// Feeds an slice of halfwords into the CRC peripheral. Returns the computed checksum.
     pub fn feed_words(&mut self, bytes: &[u32]) -> u32 {
         for byte in bytes {
-            unsafe { PAC_CRC.dr().write_value(*byte as u32); }
-        }
-        unsafe {
-            PAC_CRC.dr().read()
+            unsafe {
+                PAC_CRC.dr().write_value(*byte as u32);
+            }
         }
+        unsafe { PAC_CRC.dr().read() }
     }
 }

From 43ad28b9f9b25f2b7369be33dfd1f7db5d34e330 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Mon, 27 Sep 2021 10:38:55 -0700
Subject: [PATCH 13/16] Use unborrow for CRC constructor sort feature gates fix
 repetition in CRC config names

---
 embassy-stm32/src/crc/mod.rs             |  4 +--
 embassy-stm32/src/crc/v1.rs              |  7 ++++-
 embassy-stm32/src/crc/{v2.rs => v2v3.rs} | 33 +++++++++++++-----------
 3 files changed, 26 insertions(+), 18 deletions(-)
 rename embassy-stm32/src/crc/{v2.rs => v2v3.rs} (85%)

diff --git a/embassy-stm32/src/crc/mod.rs b/embassy-stm32/src/crc/mod.rs
index 70c87ab53..2ebebc935 100644
--- a/embassy-stm32/src/crc/mod.rs
+++ b/embassy-stm32/src/crc/mod.rs
@@ -1,6 +1,6 @@
-#[cfg_attr(crc_v2, path = "v2.rs")]
 #[cfg_attr(crc_v1, path = "v1.rs")]
-#[cfg_attr(crc_v3, path = "v2.rs")]
+#[cfg_attr(crc_v2, path = "v2v3.rs")]
+#[cfg_attr(crc_v3, path = "v2v3.rs")]
 mod _version;
 
 pub use _version::Crc;
diff --git a/embassy-stm32/src/crc/v1.rs b/embassy-stm32/src/crc/v1.rs
index 09c8eecb6..8431c07f6 100644
--- a/embassy-stm32/src/crc/v1.rs
+++ b/embassy-stm32/src/crc/v1.rs
@@ -1,6 +1,9 @@
 use crate::pac::CRC as PAC_CRC;
 use crate::peripherals::CRC;
 use crate::rcc::sealed::RccPeripheral;
+use embassy_hal_common::unborrow;
+use embassy::util::Unborrow;
+
 
 pub struct Crc {
     _peripheral: CRC,
@@ -8,12 +11,14 @@ pub struct Crc {
 
 impl Crc {
     /// Instantiates the CRC32 peripheral and initializes it to default values.
-    pub fn new(peripheral: CRC) -> Self {
+    pub fn new(peripheral: impl Unborrow<Target= CRC>) -> Self {
         // Note: enable and reset come from RccPeripheral.
         // enable CRC clock in RCC.
         CRC::enable();
         // Reset CRC to default values.
         CRC::reset();
+        // Unborrow the peripheral
+        unborrow!(peripheral);
         let mut instance = Self {
             _peripheral: peripheral,
         };
diff --git a/embassy-stm32/src/crc/v2.rs b/embassy-stm32/src/crc/v2v3.rs
similarity index 85%
rename from embassy-stm32/src/crc/v2.rs
rename to embassy-stm32/src/crc/v2v3.rs
index 7705b4285..91c24215c 100644
--- a/embassy-stm32/src/crc/v2.rs
+++ b/embassy-stm32/src/crc/v2v3.rs
@@ -2,18 +2,20 @@ use crate::pac::crc::vals;
 use crate::pac::CRC as PAC_CRC;
 use crate::peripherals::CRC;
 use crate::rcc::sealed::RccPeripheral;
+use embassy_hal_common::unborrow;
+use embassy::util::Unborrow;
 
 pub struct Crc {
     _peripheral: CRC,
-    _config: CrcConfig,
+    _config: Config,
 }
 
-pub enum CrcConfigError {
+pub enum ConfigError {
     InvalidPolynomial,
 }
 
-pub struct CrcConfig {
-    reverse_in: CrcInputReverseConfig,
+pub struct Config {
+    reverse_in: InputReverseConfig,
     reverse_out: bool,
     #[cfg(crc_v3)]
     poly_size: PolySize,
@@ -22,27 +24,27 @@ pub struct CrcConfig {
     crc_poly: u32,
 }
 
-pub enum CrcInputReverseConfig {
+pub enum InputReverseConfig {
     None,
     Byte,
     Halfword,
     Word,
 }
 
-impl CrcConfig {
+impl Config {
     pub fn new(
-        reverse_in: CrcInputReverseConfig,
+        reverse_in: InputReverseConfig,
         reverse_out: bool,
         #[cfg(crc_v3)] poly_size: PolySize,
         crc_init_value: u32,
         #[cfg(crc_v3)] crc_poly: u32,
-    ) -> Result<Self, CrcConfigError> {
+    ) -> Result<Self, ConfigError> {
         // As Per RM0091 (DocID018940 Rev 9), Even polynomials are not supported.
         #[cfg(crc_v3)]
         if crc_poly % 2 == 0 {
-            return Err(CrcConfigError::InvalidPolynomial);
+            return Err(ConfigError::InvalidPolynomial);
         }
-        Ok(CrcConfig {
+        Ok(Config {
             reverse_in,
             reverse_out,
             #[cfg(crc_v3)]
@@ -64,12 +66,13 @@ pub enum PolySize {
 
 impl Crc {
     /// Instantiates the CRC32 peripheral and initializes it to default values.
-    pub fn new(peripheral: CRC, config: CrcConfig) -> Self {
+    pub fn new(peripheral: impl Unborrow<Target= CRC>, config: Config) -> Self {
         // Note: enable and reset come from RccPeripheral.
         // enable CRC clock in RCC.
         CRC::enable();
         // Reset CRC to default values.
         CRC::reset();
+        unborrow!(peripheral);
         let mut instance = Self {
             _peripheral: peripheral,
             _config: config,
@@ -104,10 +107,10 @@ impl Crc {
                 });
                 // configure reverse input
                 w.set_rev_in(match self._config.reverse_in {
-                    CrcInputReverseConfig::None => vals::RevIn::NORMAL,
-                    CrcInputReverseConfig::Byte => vals::RevIn::BYTE,
-                    CrcInputReverseConfig::Halfword => vals::RevIn::HALFWORD,
-                    CrcInputReverseConfig::Word => vals::RevIn::WORD,
+                    InputReverseConfig::None => vals::RevIn::NORMAL,
+                    InputReverseConfig::Byte => vals::RevIn::BYTE,
+                    InputReverseConfig::Halfword => vals::RevIn::HALFWORD,
+                    InputReverseConfig::Word => vals::RevIn::WORD,
                 });
                 // configure the polynomial.
                 #[cfg(crc_v3)]

From e36d4f460a74ce9cfb55975aa9a382ed53231aca Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Mon, 27 Sep 2021 10:46:09 -0700
Subject: [PATCH 14/16] Fix variable names in crc_v2/v3. removed `reclaim` in
 crc_v1. used write instead of modify. renamed `init` to `reset` in crc_v1.

---
 embassy-stm32/src/crc/v1.rs   | 10 ++--------
 embassy-stm32/src/crc/v2v3.rs | 26 +++++++++++++-------------
 2 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/embassy-stm32/src/crc/v1.rs b/embassy-stm32/src/crc/v1.rs
index 8431c07f6..fc6d6945d 100644
--- a/embassy-stm32/src/crc/v1.rs
+++ b/embassy-stm32/src/crc/v1.rs
@@ -22,12 +22,12 @@ impl Crc {
         let mut instance = Self {
             _peripheral: peripheral,
         };
-        instance.init();
+        instance.reset();
         instance
     }
 
     /// Resets the CRC unit to default value (0xFFFF_FFFF)
-    pub fn init(&mut self) {
+    pub fn reset(&mut self) {
         unsafe { PAC_CRC.cr().write(|w| w.set_reset(true)) };
     }
 
@@ -51,10 +51,4 @@ impl Crc {
         unsafe { PAC_CRC.dr().read() }
     }
 
-    /// Reclaims the CRC peripheral.
-    pub fn release(self) -> CRC {
-        CRC::disable();
-
-        self._peripheral
-    }
 }
diff --git a/embassy-stm32/src/crc/v2v3.rs b/embassy-stm32/src/crc/v2v3.rs
index 91c24215c..78334d6cf 100644
--- a/embassy-stm32/src/crc/v2v3.rs
+++ b/embassy-stm32/src/crc/v2v3.rs
@@ -99,7 +99,7 @@ impl Crc {
 
             // configure CR components
             // (reverse I/O, polysize, poly)
-            PAC_CRC.cr().modify(|w| {
+            PAC_CRC.cr().write(|w| {
                 // configure reverse output
                 w.set_rev_out(match self._config.reverse_out {
                     true => vals::RevOut::REVERSED,
@@ -144,33 +144,33 @@ impl Crc {
         unsafe { PAC_CRC.dr().read() }
     }
     /// Feeds a halfword into the CRC peripheral. Returns the computed checksum.
-    pub fn feed_halfword(&mut self, byte: u16) -> u32 {
+    pub fn feed_halfword(&mut self, halfword: u16) -> u32 {
         unsafe {
-            PAC_CRC.dr16().write_value(byte as u32);
+            PAC_CRC.dr16().write_value(halfword as u32);
             PAC_CRC.dr().read()
         }
     }
     /// Feeds an slice of halfwords into the CRC peripheral. Returns the computed checksum.
-    pub fn feed_halfwords(&mut self, bytes: &[u16]) -> u32 {
-        for byte in bytes {
+    pub fn feed_halfwords(&mut self, halfwords: &[u16]) -> u32 {
+        for halfword in halfwords {
             unsafe {
-                PAC_CRC.dr16().write_value(*byte as u32);
+                PAC_CRC.dr16().write_value(*halfword as u32);
             }
         }
         unsafe { PAC_CRC.dr().read() }
     }
-    /// Feeds a halfword into the CRC peripheral. Returns the computed checksum.
-    pub fn feed_word(&mut self, byte: u32) -> u32 {
+    /// Feeds a words into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_word(&mut self, word: u32) -> u32 {
         unsafe {
-            PAC_CRC.dr().write_value(byte as u32);
+            PAC_CRC.dr().write_value(word as u32);
             PAC_CRC.dr().read()
         }
     }
-    /// Feeds an slice of halfwords into the CRC peripheral. Returns the computed checksum.
-    pub fn feed_words(&mut self, bytes: &[u32]) -> u32 {
-        for byte in bytes {
+    /// Feeds an slice of words into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_words(&mut self, words: &[u32]) -> u32 {
+        for word in words {
             unsafe {
-                PAC_CRC.dr().write_value(*byte as u32);
+                PAC_CRC.dr().write_value(*word as u32);
             }
         }
         unsafe { PAC_CRC.dr().read() }

From a26ffeb84bf49af342526241feca83ba41fe5b53 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Mon, 27 Sep 2021 10:49:32 -0700
Subject: [PATCH 15/16] Cargo fmt

---
 embassy-stm32/src/crc/v1.rs   | 6 ++----
 embassy-stm32/src/crc/v2v3.rs | 4 ++--
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/embassy-stm32/src/crc/v1.rs b/embassy-stm32/src/crc/v1.rs
index fc6d6945d..c33eea316 100644
--- a/embassy-stm32/src/crc/v1.rs
+++ b/embassy-stm32/src/crc/v1.rs
@@ -1,9 +1,8 @@
 use crate::pac::CRC as PAC_CRC;
 use crate::peripherals::CRC;
 use crate::rcc::sealed::RccPeripheral;
-use embassy_hal_common::unborrow;
 use embassy::util::Unborrow;
-
+use embassy_hal_common::unborrow;
 
 pub struct Crc {
     _peripheral: CRC,
@@ -11,7 +10,7 @@ pub struct Crc {
 
 impl Crc {
     /// Instantiates the CRC32 peripheral and initializes it to default values.
-    pub fn new(peripheral: impl Unborrow<Target= CRC>) -> Self {
+    pub fn new(peripheral: impl Unborrow<Target = CRC>) -> Self {
         // Note: enable and reset come from RccPeripheral.
         // enable CRC clock in RCC.
         CRC::enable();
@@ -50,5 +49,4 @@ impl Crc {
     pub fn read(&self) -> u32 {
         unsafe { PAC_CRC.dr().read() }
     }
-
 }
diff --git a/embassy-stm32/src/crc/v2v3.rs b/embassy-stm32/src/crc/v2v3.rs
index 78334d6cf..1ca529568 100644
--- a/embassy-stm32/src/crc/v2v3.rs
+++ b/embassy-stm32/src/crc/v2v3.rs
@@ -2,8 +2,8 @@ use crate::pac::crc::vals;
 use crate::pac::CRC as PAC_CRC;
 use crate::peripherals::CRC;
 use crate::rcc::sealed::RccPeripheral;
-use embassy_hal_common::unborrow;
 use embassy::util::Unborrow;
+use embassy_hal_common::unborrow;
 
 pub struct Crc {
     _peripheral: CRC,
@@ -66,7 +66,7 @@ pub enum PolySize {
 
 impl Crc {
     /// Instantiates the CRC32 peripheral and initializes it to default values.
-    pub fn new(peripheral: impl Unborrow<Target= CRC>, config: Config) -> Self {
+    pub fn new(peripheral: impl Unborrow<Target = CRC>, config: Config) -> Self {
         // Note: enable and reset come from RccPeripheral.
         // enable CRC clock in RCC.
         CRC::enable();

From 07e20a74431617c4c4130dec2e70f77a439baad9 Mon Sep 17 00:00:00 2001
From: Joshua Salzedo <joshuasalzedo@gmail.com>
Date: Mon, 27 Sep 2021 11:17:31 -0700
Subject: [PATCH 16/16] Pub use version-specific CRC symbols, not just the CRC
 struct.

---
 embassy-stm32/src/crc/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/embassy-stm32/src/crc/mod.rs b/embassy-stm32/src/crc/mod.rs
index 2ebebc935..63f7ad9ba 100644
--- a/embassy-stm32/src/crc/mod.rs
+++ b/embassy-stm32/src/crc/mod.rs
@@ -3,4 +3,4 @@
 #[cfg_attr(crc_v3, path = "v2v3.rs")]
 mod _version;
 
-pub use _version::Crc;
+pub use _version::*;