diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0664851..b71828d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,6 +5,7 @@ add_library(f4ll STATIC
     src/fault.cpp
     src/memcpy_dma.cpp
     src/packet_usart.cpp
+    src/ringbuffer.cpp
     src/str_util.cpp
     src/usart_core.cpp
 )
diff --git a/inc/f4ll/ringbuffer.h b/inc/f4ll/ringbuffer.h
index acf39d1..9ba2ccc 100644
--- a/inc/f4ll/ringbuffer.h
+++ b/inc/f4ll/ringbuffer.h
@@ -72,10 +72,11 @@ public:
     virtual size_type unused() const = 0;
 };
 
-template <iringbuffer::size_type SZ> class ringbuffer : public iringbuffer
+//
+class ringbuffer_ext : public iringbuffer
 {
 public:
-    ringbuffer() = default;
+    ringbuffer_ext(uint8_t *bptr, size_type bsize);
 
     size_type put(uint8_t const *data, size_type len) override;
     void commit() override;
@@ -89,7 +90,8 @@ public:
     size_type unused() const override;
 
 private:
-    uint8_t m_buffer[SZ];        //!< Data bufer
+    uint8_t *m_buffer;           //!< Data bufer
+    size_type const m_bsize;     //!< Data buffer size
     size_type m_head = 0;        //!< Write position
     size_type m_head_shadow = 0; //!< Shadowed write position for collecting data
                                  //!< before committing it
@@ -99,120 +101,20 @@ private:
 };
 
 //
-template <iringbuffer::size_type SZ> iringbuffer::size_type ringbuffer<SZ>::put(uint8_t const *data, size_type len)
+template <iringbuffer::size_type SZ> class ringbuffer : public ringbuffer_ext
 {
-    size_type chunk1 = 0;
-    size_type chunk2 = 0;
+public:
+    ringbuffer();
 
-    if (!data || !len) {
-        return 0;
-    }
-
-    size_type max_len = unused();
-    len = len < max_len ? len : max_len;
-
-    chunk1 = sizeof(m_buffer) - m_head_shadow;
-    if (chunk1 >= len) {
-        chunk1 = len;
-    } else {
-        chunk2 = len - chunk1;
-    }
-
-    std::memcpy(m_buffer + m_head_shadow, data, chunk1);
-    m_head_shadow += chunk1;
-    if (m_head_shadow == sizeof(m_buffer)) {
-        m_head_shadow = 0;
-    }
-
-    if (chunk2) {
-        std::memcpy(m_buffer, data + chunk1, chunk2);
-        m_head_shadow += chunk2;
-        if (m_head_shadow == sizeof(m_buffer)) {
-            m_head_shadow = 0;
-        }
-    }
-
-    return len;
-}
-
-template <iringbuffer::size_type SZ> void ringbuffer<SZ>::commit()
-{
-    m_head = m_head_shadow;
+private:
+    uint8_t m_buffer[SZ];
 };
 
-template <iringbuffer::size_type SZ> bool ringbuffer<SZ>::get_chunk(size_type len_requested, uint8_t const *&data, size_type &len) const
+//
+template <iringbuffer::size_type SZ>
+ringbuffer<SZ>::ringbuffer()
+    : ringbuffer_ext(m_buffer, SZ)
 {
-    if (!len_requested) {
-        return false;
-    }
-
-    size_type head = m_head;
-    size_type tail = m_tail;
-    size_type chunk_size = head >= tail ? head - tail : sizeof(m_buffer) - tail;
-
-    if (!chunk_size) {
-        len = 0;
-        return false;
-    }
-
-    if (chunk_size > len_requested) {
-        chunk_size = len_requested;
-    }
-    data = m_buffer + tail;
-    len = chunk_size;
-
-    tail += chunk_size;
-    if (tail == sizeof(m_buffer)) {
-        tail = 0;
-    }
-
-    return tail != head;
-}
-
-template <iringbuffer::size_type SZ> void ringbuffer<SZ>::consumed(size_type len)
-{
-    if (!len) {
-        return;
-    }
-    m_tail += len;
-    if (m_tail == sizeof(m_buffer)) {
-        m_tail = 0;
-    }
-}
-
-template <iringbuffer::size_type SZ> iringbuffer::size_type ringbuffer<SZ>::uncommited() const
-{
-    return marker_diff(m_head_shadow, m_head);
-}
-
-template <iringbuffer::size_type SZ> iringbuffer::size_type ringbuffer<SZ>::commited() const
-{
-    return marker_diff(m_head, m_tail);
-}
-
-template <iringbuffer::size_type SZ> void ringbuffer<SZ>::discard()
-{
-    m_head_shadow = m_head;
-}
-
-template <iringbuffer::size_type SZ> iringbuffer::size_type ringbuffer<SZ>::size() const
-{
-    return SZ;
-}
-
-template <iringbuffer::size_type SZ> iringbuffer::size_type ringbuffer<SZ>::used() const
-{
-    return marker_diff(m_head_shadow, m_tail);
-}
-
-template <iringbuffer::size_type SZ> iringbuffer::size_type ringbuffer<SZ>::unused() const
-{
-    return SZ - used() - 1;
-}
-
-template <iringbuffer::size_type SZ> iringbuffer::size_type ringbuffer<SZ>::marker_diff(size_type m1, size_type m2) const
-{
-    return (m1 >= m2) ? (m1 - m2) : (SZ - m2 + m1);
 }
 
 } // namespace f1ll
\ No newline at end of file
diff --git a/src/ringbuffer.cpp b/src/ringbuffer.cpp
new file mode 100644
index 0000000..5354f95
--- /dev/null
+++ b/src/ringbuffer.cpp
@@ -0,0 +1,128 @@
+#include <f4ll/ringbuffer.h>
+
+namespace f4ll {
+
+ringbuffer_ext::ringbuffer_ext(uint8_t *bptr, size_type bsize)
+    : m_buffer(bptr),
+      m_bsize(bsize)
+{
+}
+
+iringbuffer::size_type ringbuffer_ext::put(uint8_t const *data, size_type len)
+{
+    size_type chunk1 = 0;
+    size_type chunk2 = 0;
+
+    if (!data || !len) {
+        return 0;
+    }
+
+    size_type max_len = unused();
+    len = len < max_len ? len : max_len;
+
+    chunk1 = m_bsize - m_head_shadow;
+    if (chunk1 >= len) {
+        chunk1 = len;
+    } else {
+        chunk2 = len - chunk1;
+    }
+
+    std::memcpy(m_buffer + m_head_shadow, data, chunk1);
+    m_head_shadow += chunk1;
+    if (m_head_shadow == m_bsize) {
+        m_head_shadow = 0;
+    }
+
+    if (chunk2) {
+        std::memcpy(m_buffer, data + chunk1, chunk2);
+        m_head_shadow += chunk2;
+        if (m_head_shadow == m_bsize) {
+            m_head_shadow = 0;
+        }
+    }
+
+    return len;
+}
+
+void ringbuffer_ext::commit()
+{
+    m_head = m_head_shadow;
+}
+
+bool ringbuffer_ext::get_chunk(size_type len_requested, uint8_t const *&data, size_type &len) const
+{
+    if (!len_requested) {
+        return false;
+    }
+
+    size_type head = m_head;
+    size_type tail = m_tail;
+    size_type chunk_size = head >= tail ? head - tail : m_bsize - tail;
+
+    if (!chunk_size) {
+        len = 0;
+        return tail != head;
+    }
+
+    if (chunk_size > len_requested) {
+        chunk_size = len_requested;
+    }
+    data = m_buffer + tail;
+    len = chunk_size;
+
+    tail += chunk_size;
+    if (tail == m_bsize) {
+        tail = 0;
+    }
+
+    return tail != head;
+}
+
+void ringbuffer_ext::consumed(size_type len)
+{
+    if (!len) {
+        return;
+    }
+    m_tail += len;
+    if (m_tail == m_bsize) {
+        m_tail = 0;
+    }
+}
+
+iringbuffer::size_type ringbuffer_ext::uncommited() const
+{
+    return marker_diff(m_head_shadow, m_head);
+}
+
+iringbuffer::size_type ringbuffer_ext::commited() const
+{
+    return marker_diff(m_head, m_tail);
+}
+
+void ringbuffer_ext::discard()
+{
+    m_head_shadow = m_head;
+}
+
+iringbuffer::size_type ringbuffer_ext::size() const
+{
+    return m_bsize;
+}
+
+iringbuffer::size_type ringbuffer_ext::used() const
+{
+    return marker_diff(m_head_shadow, m_tail);
+}
+
+iringbuffer::size_type ringbuffer_ext::unused() const
+{
+    return m_bsize - used() - 1;
+}
+
+iringbuffer::size_type ringbuffer_ext::marker_diff(size_type m1, size_type m2) const
+{
+    return (m1 >= m2) ? (m1 - m2) : (m_bsize - m2 + m1);
+}
+
+//
+}
\ No newline at end of file