diff --git a/inc/f4ll/console_handler.h b/inc/f4ll/console_handler.h
index 9ab5e4a..14e15a6 100644
--- a/inc/f4ll/console_handler.h
+++ b/inc/f4ll/console_handler.h
@@ -8,8 +8,10 @@
 #pragma once
 
 #include <f4ll/initialized_singleton.h>
-#include <f4ll/packet_usart.h>
 #include <f4ll/ringbuffer.h>
+#include <f4ll/usart_core.h>
+
+#include <platform/dma_ll.h>
 
 namespace f4ll {
 
@@ -40,16 +42,16 @@ private:
     void setup_receive(void);
 
     // LL_UsartCore pure virtual function implementations
-    virtual void receiver_idle(void) override;
-    virtual void transmission_complete(void) override;
-    virtual void framing_error(void) override;
-    virtual void overrun(void) override;
-    virtual void rx_dma_transfer_complete(void) override;
-    virtual void rx_dma_half_transfer(void) override;
-    virtual void rx_dma_error(dma_helper::dma_error_type reason) override;
-    virtual void tx_dma_transfer_complete(void) override;
-    virtual void tx_dma_half_transfer(void) override;
-    virtual void tx_dma_error(dma_helper::dma_error_type reason) override;
+    void receiver_idle(void) override;
+    void transmission_complete(void) override;
+    void framing_error(void) override;
+    void overrun(void) override;
+    void rx_dma_transfer_complete(void) override;
+    void rx_dma_half_transfer(void) override;
+    void rx_dma_error(dma_helper::dma_error_type reason) override;
+    void tx_dma_transfer_complete(void) override;
+    void tx_dma_half_transfer(void) override;
+    void tx_dma_error(dma_helper::dma_error_type reason) override;
 
     ringbuffer_ext m_tx_buffer;
     size_type m_bytes_sent = 0;
diff --git a/inc/f4ll/crc_handler.h b/inc/f4ll/crc_handler.h
index 8fb6b27..fbc7037 100644
--- a/inc/f4ll/crc_handler.h
+++ b/inc/f4ll/crc_handler.h
@@ -6,10 +6,12 @@
  */
 #pragma once
 
+#include <cstdint>
+
+#include <platform/dma_ll.h>
+
 #include <f4ll/dma_helper.h>
 #include <f4ll/initialized_singleton.h>
-#include <inttypes.h>
-#include <platform/dma_ll.h>
 
 namespace f4ll {
 
diff --git a/inc/f4ll/dma_helper.h b/inc/f4ll/dma_helper.h
index 0b8719e..4f52f1e 100644
--- a/inc/f4ll/dma_helper.h
+++ b/inc/f4ll/dma_helper.h
@@ -7,7 +7,8 @@
 
 #pragma once
 
-#include <inttypes.h>
+#include <cstdint>
+
 #include <platform/dma_ll.h>
 
 namespace f4ll {
diff --git a/inc/f4ll/fault.h b/inc/f4ll/fault.h
index 8bb1f2e..42293c4 100644
--- a/inc/f4ll/fault.h
+++ b/inc/f4ll/fault.h
@@ -5,6 +5,8 @@
 #define FAULT_REASON_BUS_FAULT 3
 #define FAULT_REASON_USAGE_FAULT 4
 
+#include <cstdint>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/inc/f4ll/irq_lock.h b/inc/f4ll/irq_lock.h
index b36ef75..6d4b356 100644
--- a/inc/f4ll/irq_lock.h
+++ b/inc/f4ll/irq_lock.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <inttypes.h>
+#include <cstdint>
 #include <stm32f4xx.h>
 
 namespace f4ll {
diff --git a/inc/f4ll/memcpy_dma.h b/inc/f4ll/memcpy_dma.h
index 4fcd299..ab728d1 100644
--- a/inc/f4ll/memcpy_dma.h
+++ b/inc/f4ll/memcpy_dma.h
@@ -6,6 +6,8 @@
  */
 #pragma once
 
+#include <cstdint>
+
 #include <f4ll/dma_helper.h>
 #include <f4ll/initialized_singleton.h>
 
diff --git a/inc/f4ll/packet_usart.h b/inc/f4ll/packet_usart.h
index 1bb9a96..0fd425c 100644
--- a/inc/f4ll/packet_usart.h
+++ b/inc/f4ll/packet_usart.h
@@ -95,7 +95,7 @@ private:
     virtual void tx_dma_half_transfer(void) override;
     virtual void tx_dma_error(dma_helper::dma_error_type reason) override;
 
-    struct Buffer
+    struct buffer
     {
         packet pkt;
         // transfer area ends here
@@ -115,8 +115,8 @@ private:
     crc_handler::slot<2> m_crc_slot;
     ihs_usart_callback *m_user_callback = nullptr;
     uintptr_t m_user_callback_param = 0;
-    Buffer m_tx_buffer;
-    Buffer m_rx_buffers[2];
+    buffer m_tx_buffer;
+    buffer m_rx_buffers[2];
 };
 
 }
diff --git a/inc/f4ll/ringbuffer.h b/inc/f4ll/ringbuffer.h
index 82f1891..c2dc08d 100644
--- a/inc/f4ll/ringbuffer.h
+++ b/inc/f4ll/ringbuffer.h
@@ -9,7 +9,6 @@
 
 #include <cstddef>
 #include <cstdint>
-#include <cstring>
 
 namespace f4ll {
 
@@ -131,4 +130,4 @@ ringbuffer<SZ>::ringbuffer()
 {
 }
 
-} // namespace f1ll
\ No newline at end of file
+} // namespace f1ll
diff --git a/inc/f4ll/singleton.h b/inc/f4ll/singleton.h
new file mode 100644
index 0000000..b4278a8
--- /dev/null
+++ b/inc/f4ll/singleton.h
@@ -0,0 +1,23 @@
+#pragma once
+
+namespace f4ll {
+
+template <typename T> class singleton
+{
+public:
+    static T &instance()
+    {
+        static T instance;
+        return instance;
+    }
+
+protected:
+    singleton() = default;
+    singleton(const singleton &) = delete;
+    singleton &operator=(const singleton &) = delete;
+    static T *m_instance;
+};
+
+template <typename T> T *singleton<T>::m_instance = nullptr;
+
+} //  namespace f1ll {
diff --git a/src/console_handler.cpp b/src/console_handler.cpp
index 2ddd37d..e1955f1 100644
--- a/src/console_handler.cpp
+++ b/src/console_handler.cpp
@@ -5,9 +5,7 @@
  *      Author: abody
  */
 
-#include <cstddef>
 #include <f4ll/console_handler.h>
-#include <f4ll/irq_lock.h>
 #include <f4ll/str_util.h>
 
 #include <cstring>
diff --git a/src/fault.cpp b/src/fault.cpp
index 83ae3c2..d26d544 100644
--- a/src/fault.cpp
+++ b/src/fault.cpp
@@ -5,8 +5,6 @@
  *      Author: abody
  *      -c "tpiu config internal <logfile_full_path> uart off <cpufreq>"
  */
-#include <inttypes.h>
-// #include <core_cm4.h>
 #include <f4ll/fault.h>
 #include <f4ll/str_util.h>
 #include <stm32f4xx.h>
diff --git a/src/packet_usart.cpp b/src/packet_usart.cpp
index 046d5ea..a1945b6 100644
--- a/src/packet_usart.cpp
+++ b/src/packet_usart.cpp
@@ -183,7 +183,7 @@ void packet_usart::crc_succeeded(uintptr_t callback_param, uint32_t crc, uint8_t
 {
     (void)task;
 
-    Buffer &buf(m_rx_buffers[static_cast<int>(callback_param)]);
+    buffer &buf(m_rx_buffers[static_cast<int>(callback_param)]);
 
     buf.busy = 1;
     if (*(uint32_t *)(buf.pkt.payload + round_up_to_4((uint16_t)buf.pkt.header.payload_length)) != crc) {
@@ -201,7 +201,7 @@ void packet_usart::crc_failed(uintptr_t callback_param, uint32_t crc, uint8_t ta
     (void)crc;
     (void)task;
 
-    Buffer &buf(m_rx_buffers[static_cast<int>(callback_param)]);
+    buffer &buf(m_rx_buffers[static_cast<int>(callback_param)]);
     buf.busy = buf.error = true;
     buf.error_info = 0;
     ++m_stats.payload_errror;
diff --git a/src/ringbuffer.cpp b/src/ringbuffer.cpp
index c5a46e3..ae81ac2 100644
--- a/src/ringbuffer.cpp
+++ b/src/ringbuffer.cpp
@@ -1,5 +1,7 @@
 #include <f4ll/ringbuffer.h>
 
+#include <cstring>
+
 namespace f4ll {
 
 ringbuffer_ext::ringbuffer_ext(uint8_t *bptr, size_type bsize)
@@ -147,4 +149,4 @@ iringbuffer::size_type ringbuffer_ext::marker_diff(size_type m1, size_type m2) c
 }
 
 //
-}
\ No newline at end of file
+}
diff --git a/src/str_util.cpp b/src/str_util.cpp
index 54b95df..9b6ef95 100644
--- a/src/str_util.cpp
+++ b/src/str_util.cpp
@@ -1,7 +1,5 @@
 #include <f4ll/str_util.h>
 
-#include <cstdint>
-
 //////////////////////////////////////////////////////////////////////////////
 size_t strcpy_ex(char *dst, char const *src)
 {