diff --git a/.travis.yml b/.travis.yml
index abb43697..0ac07cee 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -68,9 +68,9 @@ after_success:
 
 before_install:
   - sudo apt-get update -qq
-  - wget https://cmake.org/files/v3.11/cmake-3.11.4-Linux-x86_64.sh
+  - wget https://cmake.org/files/v3.14/cmake-3.14.2-Linux-x86_64.sh
   - mkdir /opt/cmake
-  - sh cmake-3.11.4-Linux-x86_64.sh --prefix=/opt/cmake --skip-license
+  - sh cmake-3.14.2-Linux-x86_64.sh --prefix=/opt/cmake --skip-license
   - wget https://launchpad.net/%7Eboost-latest/+archive/ubuntu/ppa/+files/libboost1.55-dev_1.55.0-1ppa1%7Esaucy1_amd64.deb
   - sudo dpkg --install libboost1.55-dev_1.55.0-1ppa1~saucy1_amd64.deb
   # - openssl aes-256-cbc -K $encrypted_eb6359394db6_key -iv $encrypted_eb6359394db6_iv -in config/travisci_rsa.enc -out config/travisci_rsa -d
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3c3cbaa4..db2d6d17 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.10)
+cmake_minimum_required(VERSION 3.14)
 # Prevent in source build, add this options before project keyword
 set(CMAKE_DISABLE_SOURCE_CHANGES ON)
 set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)
@@ -7,15 +7,21 @@ project(lib_bluetoe CXX)
 add_library(bluetoe_iface INTERFACE)
 add_library(bluetoe::iface ALIAS bluetoe_iface)
 target_include_directories(bluetoe_iface INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
+target_compile_features(bluetoe_iface INTERFACE cxx_std_11)
+
 
 add_subdirectory(bluetoe/link_layer)
+add_subdirectory(bluetoe/scheduled_radio)
+add_subdirectory(bluetoe/hci)
 add_subdirectory(bluetoe/utility)
 add_subdirectory(bluetoe/sm)
 add_subdirectory(bluetoe/services)
 
 if (CMAKE_CROSSCOMPILING)
     add_subdirectory(bluetoe/bindings/nrf51)
-endif ()
+endif()
+
+add_subdirectory(bluetoe/bindings/hci)
 
 if (NOT CMAKE_CROSSCOMPILING)
     enable_testing()
diff --git a/bluetoe/bindings/hci/CMakeLists.txt b/bluetoe/bindings/hci/CMakeLists.txt
new file mode 100644
index 00000000..b66e4662
--- /dev/null
+++ b/bluetoe/bindings/hci/CMakeLists.txt
@@ -0,0 +1,13 @@
+add_library(bluetoe_bindings_hci_libusb STATIC libusb.cpp)
+add_library(bluetoe::bindings::hci_libusb ALIAS bluetoe_bindings_hci_libusb)
+
+target_include_directories(bluetoe_bindings_hci_libusb
+    INTERFACE
+        include_libusb)
+
+target_link_libraries(bluetoe_bindings_hci_libusb
+    PUBLIC
+        bluetoe::hci
+        bluetoe::utility
+        bluetoe::linklayer
+)
diff --git a/bluetoe/bindings/hci/include_libusb/bluetoe/device.hpp b/bluetoe/bindings/hci/include_libusb/bluetoe/device.hpp
new file mode 100644
index 00000000..3cc5eea5
--- /dev/null
+++ b/bluetoe/bindings/hci/include_libusb/bluetoe/device.hpp
@@ -0,0 +1,14 @@
+#ifndef BLUETOE_BINDINGS_HCI_DEVICE_HPP
+#define BLUETOE_BINDINGS_HCI_DEVICE_HPP
+
+#include <bluetoe/link_layer.hpp>
+#include <bluetoe/libsub.hpp>
+
+namespace bluetoe
+{
+    template < class Server, typename ... Options >
+    using device = bluetoe::hci::link_layer< Server, hci_details::libsub_transport, Options... >;
+}
+
+#endif
+
diff --git a/bluetoe/bindings/hci/include_libusb/bluetoe/libsub.hpp b/bluetoe/bindings/hci/include_libusb/bluetoe/libsub.hpp
new file mode 100644
index 00000000..8721cc31
--- /dev/null
+++ b/bluetoe/bindings/hci/include_libusb/bluetoe/libsub.hpp
@@ -0,0 +1,14 @@
+#ifndef BLUETOE_BINDINGS_HCI_LIBUSB_HPP
+#define BLUETOE_BINDINGS_HCI_LIBUSB_HPP
+
+namespace bluetoe {
+
+    namespace hci_details {
+        template < typename LinkLayer >
+        class libsub_transport {
+
+        };
+    }
+}
+
+#endif
diff --git a/bluetoe/bindings/hci/libusb.cpp b/bluetoe/bindings/hci/libusb.cpp
new file mode 100644
index 00000000..e69de29b
diff --git a/bluetoe/bindings/nrf51/CMakeLists.txt b/bluetoe/bindings/nrf51/CMakeLists.txt
index 242934f6..1c76e66e 100644
--- a/bluetoe/bindings/nrf51/CMakeLists.txt
+++ b/bluetoe/bindings/nrf51/CMakeLists.txt
@@ -2,8 +2,21 @@ add_library(bluetoe_bindings_nrf51 STATIC
             nrf51.cpp)
 add_library(bluetoe::bindings::nrf51 ALIAS bluetoe_bindings_nrf51)
 
+# Currently nrf52 is equal to nrf51, which is wrong if one looks at the details
+add_library(bluetoe::bindings::nrf52 ALIAS bluetoe_bindings_nrf51)
+
 target_include_directories(bluetoe_bindings_nrf51 PUBLIC include)
 
-target_link_libraries(bluetoe_bindings_nrf51 PUBLIC bluetoe::utility bluetoe::sm bluetoe::iface bluetoe::linklayer PRIVATE toolchain::${BINDING})
+target_link_libraries(bluetoe_bindings_nrf51
+    PUBLIC
+        bluetoe::utility
+        bluetoe::sm
+        bluetoe::iface
+        bluetoe::linklayer
+        bluetoe::scheduled_radio
+    PRIVATE
+        toolchain::${BINDING}
+)
+
 target_compile_features(bluetoe_bindings_nrf51 PRIVATE cxx_std_11)
 target_compile_options(bluetoe_bindings_nrf51 PRIVATE -Wall -pedantic -Wextra -Wfatal-errors -Wno-parentheses)
diff --git a/bluetoe/hci/CMakeLists.txt b/bluetoe/hci/CMakeLists.txt
new file mode 100644
index 00000000..1e1ff61c
--- /dev/null
+++ b/bluetoe/hci/CMakeLists.txt
@@ -0,0 +1,7 @@
+cmake_policy(SET CMP0079 NEW)
+
+add_library(bluetoe_hci INTERFACE)
+add_library(bluetoe::hci ALIAS bluetoe_hci)
+
+target_include_directories(bluetoe_hci INTERFACE include)
+target_link_libraries(bluetoe_hci INTERFACE bluetoe::sm bluetoe::iface)
diff --git a/bluetoe/hci/include/bluetoe/link_layer.hpp b/bluetoe/hci/include/bluetoe/link_layer.hpp
new file mode 100644
index 00000000..da3a6677
--- /dev/null
+++ b/bluetoe/hci/include/bluetoe/link_layer.hpp
@@ -0,0 +1,64 @@
+#ifndef BLUETOE_HCI_LINK_LAYER_HPP
+#define BLUETOE_HCI_LINK_LAYER_HPP
+
+#include <bluetoe/address.hpp>
+
+namespace bluetoe {
+namespace hci {
+
+    /**
+     * @brief link layer implementation based on HCI
+     */
+    template <
+        class Server,
+        template < typename >
+        class Transport,
+        typename ... Options
+    >
+    class link_layer : Transport< link_layer< Server, Transport, Options... > >
+    {
+    public:
+        /**
+         * @brief this function passes the CPU to the link layer implementation
+         *
+         * This function should return on certain events to alow user code to do
+         * usefull things. Details depend on the ScheduleRadio implemention.
+         */
+        void run( Server& );
+
+        /**
+         * @brief initiating the change of communication parameters of an established connection
+         *
+         * If it was not possible to initiate the connection parameter update, the function returns false.
+         * @todo Add parameter that identifies the connection.
+         */
+        bool connection_parameter_update_request( std::uint16_t interval_min, std::uint16_t interval_max, std::uint16_t latency, std::uint16_t timeout );
+
+        /**
+         * @brief terminates the give connection
+         *
+         * @todo Add parameter that identifies the connection.
+         */
+        void disconnect();
+
+        /**
+         * @brief fills the given buffer with l2cap advertising payload
+         */
+        std::size_t fill_l2cap_advertising_data( std::uint8_t* buffer, std::size_t buffer_size ) const;
+
+        /**
+         * @brief returns the own local device address
+         */
+        const bluetoe::link_layer::device_address& local_address() const;
+    private:
+    };
+
+    // implementation
+    template < class Server, template < typename > class Transport, typename ... Options >
+    void link_layer< Server, Transport, Options... >::run( Server& )
+    {
+    }
+}
+}
+
+#endif
diff --git a/bluetoe/link_layer/CMakeLists.txt b/bluetoe/link_layer/CMakeLists.txt
index b40e40b2..73652128 100644
--- a/bluetoe/link_layer/CMakeLists.txt
+++ b/bluetoe/link_layer/CMakeLists.txt
@@ -6,6 +6,5 @@ add_library(bluetoe_linklayer STATIC
 add_library(bluetoe::linklayer ALIAS bluetoe_linklayer)
 
 target_include_directories(bluetoe_linklayer PUBLIC include)
-target_link_libraries(bluetoe_linklayer PRIVATE bluetoe::sm bluetoe::iface)
 target_compile_features(bluetoe_linklayer PRIVATE cxx_std_11)
 target_compile_options(bluetoe_linklayer PRIVATE -Wall -pedantic -Wextra -Wfatal-errors)
diff --git a/bluetoe/scheduled_radio/CMakeLists.txt b/bluetoe/scheduled_radio/CMakeLists.txt
new file mode 100644
index 00000000..0c3b827e
--- /dev/null
+++ b/bluetoe/scheduled_radio/CMakeLists.txt
@@ -0,0 +1,5 @@
+add_library(bluetoe_scheduled_radio INTERFACE)
+add_library(bluetoe::scheduled_radio ALIAS bluetoe_scheduled_radio)
+
+target_include_directories(bluetoe_scheduled_radio INTERFACE include)
+target_compile_features(bluetoe_linklayer PRIVATE cxx_std_11)
diff --git a/bluetoe/link_layer/include/bluetoe/advertising.hpp b/bluetoe/scheduled_radio/include/bluetoe/advertising.hpp
similarity index 99%
rename from bluetoe/link_layer/include/bluetoe/advertising.hpp
rename to bluetoe/scheduled_radio/include/bluetoe/advertising.hpp
index 12641c93..649759cc 100644
--- a/bluetoe/link_layer/include/bluetoe/advertising.hpp
+++ b/bluetoe/scheduled_radio/include/bluetoe/advertising.hpp
@@ -2,10 +2,10 @@
 #define BLUETOE_LINK_LAYER_ADVERTISING_HPP
 
 #include <bluetoe/meta_tools.hpp>
-#include "address.hpp"
-#include "buffer.hpp"
-#include "delta_time.hpp"
-#include "ll_meta_types.hpp"
+#include <bluetoe/address.hpp>
+#include <bluetoe/buffer.hpp>
+#include <bluetoe/delta_time.hpp>
+#include <bluetoe/ll_meta_types.hpp>
 
 /**
  * @file bluetoe/link_layer/advertising.hpp
diff --git a/bluetoe/link_layer/include/bluetoe/link_layer.hpp b/bluetoe/scheduled_radio/include/bluetoe/link_layer.hpp
similarity index 99%
rename from bluetoe/link_layer/include/bluetoe/link_layer.hpp
rename to bluetoe/scheduled_radio/include/bluetoe/link_layer.hpp
index 7045454a..46477c73 100644
--- a/bluetoe/link_layer/include/bluetoe/link_layer.hpp
+++ b/bluetoe/scheduled_radio/include/bluetoe/link_layer.hpp
@@ -1,17 +1,17 @@
 #ifndef BLUETOE_LINK_LAYER_LINK_LAYER_HPP
 #define BLUETOE_LINK_LAYER_LINK_LAYER_HPP
 
-#include "buffer.hpp"
-#include "delta_time.hpp"
-#include "ll_options.hpp"
-#include "address.hpp"
-#include "channel_map.hpp"
-#include "notification_queue.hpp"
-#include "connection_callbacks.hpp"
-#include "connection_event_callback.hpp"
-#include "l2cap_signaling_channel.hpp"
-#include "white_list.hpp"
-#include "advertising.hpp"
+#include <bluetoe/buffer.hpp>
+#include <bluetoe/delta_time.hpp>
+#include <bluetoe/ll_options.hpp>
+#include <bluetoe/address.hpp>
+#include <bluetoe/channel_map.hpp>
+#include <bluetoe/notification_queue.hpp>
+#include <bluetoe/connection_callbacks.hpp>
+#include <bluetoe/connection_event_callback.hpp>
+#include <bluetoe/l2cap_signaling_channel.hpp>
+#include <bluetoe/white_list.hpp>
+#include <bluetoe/advertising.hpp>
 #include <bluetoe/meta_types.hpp>
 #include <bluetoe/attribute.hpp>
 #include <bluetoe/meta_tools.hpp>
diff --git a/bluetoe/link_layer/include/bluetoe/ll_data_pdu_buffer.hpp b/bluetoe/scheduled_radio/include/bluetoe/ll_data_pdu_buffer.hpp
similarity index 100%
rename from bluetoe/link_layer/include/bluetoe/ll_data_pdu_buffer.hpp
rename to bluetoe/scheduled_radio/include/bluetoe/ll_data_pdu_buffer.hpp
diff --git a/bluetoe/link_layer/include/bluetoe/ring_buffer.hpp b/bluetoe/scheduled_radio/include/bluetoe/ring_buffer.hpp
similarity index 99%
rename from bluetoe/link_layer/include/bluetoe/ring_buffer.hpp
rename to bluetoe/scheduled_radio/include/bluetoe/ring_buffer.hpp
index eb525957..9d0a61b0 100644
--- a/bluetoe/link_layer/include/bluetoe/ring_buffer.hpp
+++ b/bluetoe/scheduled_radio/include/bluetoe/ring_buffer.hpp
@@ -5,7 +5,7 @@
 #include <cassert>
 #include <cstdlib>
 
-#include "buffer.hpp"
+#include <bluetoe/buffer.hpp>
 
 namespace bluetoe {
 namespace link_layer {
diff --git a/bluetoe/link_layer/scheduled_radio.hpp b/bluetoe/scheduled_radio/scheduled_radio.hpp
similarity index 100%
rename from bluetoe/link_layer/scheduled_radio.hpp
rename to bluetoe/scheduled_radio/scheduled_radio.hpp
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 2f94bc20..94518fea 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -1,55 +1,96 @@
-cmake_minimum_required(VERSION 3.10)
+cmake_minimum_required(VERSION 3.14)
+
 # Prevent in source build, add this options before project keyword
 set(CMAKE_DISABLE_SOURCE_CHANGES ON)
 set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)
+
 project(bluetoe_examples CXX C)
 
-if (NOT CMAKE_CROSSCOMPILING)
-    message(ERROR " examples can only be cross compiled to arm cortex-m, missing -Dtoolchain_file on cmake invocation?")
-    return()
-endif()
 if (NOT BINDING)
-    message(ERROR " A binding must be defined. Use -DBINDING=nrf51. Current available bindings are nrf51, nrf52")
-    return()
+    message(FATAL_ERROR " A binding must be defined. Use -DBINDING=nrf51. Current available bindings are nrf51, nrf52")
+endif()
+
+set(supported_bindings nrf51 nrf52 hci_libusb)
+set(cross_compile_bindings nrf51 nrf52)
+
+list(FIND supported_bindings "${BINDING}" binding_pos)
+
+if (${binding_pos} EQUAL -1)
+    message(FATAL_ERROR " not supported binding: ${BINDING}. Please choose one out of ${supported_bindings}")
+endif()
+
+if (NOT CMAKE_CROSSCOMPILING)
+    list(FIND cross_compile_bindings "${BINDING}" cross_binding_pos)
+
+    if (NOT ${cross_binding_pos} EQUAL -1)
+        message(FATAL_ERROR " examples can only be cross compiled to arm cortex-m, missing -Dtoolchain_file on cmake invocation?")
+    endif()
 endif()
 
-# include hardware specific compile options and definitions that must be apllied to the whole project
-include(${BINDING}_toolchain_support/platform.cmake)
 #set global compile options that are hardware independent, these will be used to build the applications (examples)
 #and will also be used to build bluetoe library
 # add global compile options
 add_compile_options(-ffunction-sections -fdata-sections)
-#toolchain support targets, these are C and asm only, dont add cpp flags yet
-add_subdirectory(${BINDING}_toolchain_support)
+
+if (CMAKE_CROSSCOMPILING)
+    # include hardware specific compile options and definitions that must be apllied to the whole project
+    include(${BINDING}_toolchain_support/platform.cmake)
+
+    #toolchain support targets, these are C and asm only, dont add cpp flags yet
+    add_subdirectory(${BINDING}_toolchain_support)
+endif()
+
 #add global options to cpp targets
 add_compile_options(-ftemplate-backtrace-limit=0 -fvisibility-inlines-hidden -fno-rtti -fno-exceptions)
+
 #bluetoe library
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/.. ${CMAKE_CURRENT_BINARY_DIR}/bluetoe)
-function(add_bluetoe_example target_name)
-    add_executable(${target_name} ${target_name}.cpp runtime.cpp)
-    set_target_properties(${target_name} PROPERTIES OUTPUT_NAME ${target_name}.elf)
-    add_dependencies(${target_name} linker_script)
-    target_compile_options(${target_name} PRIVATE  )
-    target_link_libraries(${target_name} PRIVATE bluetoe::iface
-                                         bluetoe::bindings::nrf51
-                                         startup::${BINDING}
-                                         toolchain::${BINDING}
-                            -lm -lstdc++ -lsupc++
-                            -T${CMAKE_CURRENT_BINARY_DIR}/${BINDING}_toolchain_support/linker_script.ld
-                            -Wl,--gc-sections -Wl,--warn-common
-                            -Wl,-Map,${CMAKE_CURRENT_BINARY_DIR}/${target_name}.map -nostdlib
-                            )
-    add_custom_target(${target_name}.artifacts ALL
-            COMMAND ${CMAKE_OBJCOPY} -S -O ihex ${target_name}.elf ${target_name}.hex
-            COMMAND ${CMAKE_OBJCOPY} -S -O binary --only-section=.text ${target_name}.elf ${target_name}.bin
-            COMMAND ${CMAKE_OBJDUMP} -hS ${target_name}.elf > ${target_name}.lss
-            COMMAND ${CMAKE_SIZE} ${target_name}.elf
-            )
-    add_dependencies(${target_name}.artifacts ${target_name})
-    add_custom_target(${target_name}.flash
-            COMMAND nrfjprog --chiperase --program ${target_name}.hex)
-    add_dependencies(${target_name}.flash ${target_name}.artifacts)
-endfunction()
+
+# Some hardware abstractions, required by the examples
+add_subdirectory(hal)
+
+if (CMAKE_CROSSCOMPILING)
+    function(add_bluetoe_example target_name)
+        add_executable(${target_name} ${target_name}.cpp runtime.cpp)
+        set_target_properties(${target_name} PROPERTIES OUTPUT_NAME ${target_name}.elf)
+        add_dependencies(${target_name} linker_script)
+        target_compile_options(${target_name} PRIVATE  )
+        target_link_libraries(${target_name} PRIVATE bluetoe::iface
+                                             bluetoe::bindings::${BINDING}
+                                             startup::${BINDING}
+                                             toolchain::${BINDING}
+                                             example_hal
+                                -lm -lstdc++ -lsupc++
+                                -T${CMAKE_CURRENT_BINARY_DIR}/${BINDING}_toolchain_support/linker_script.ld
+                                -Wl,--gc-sections -Wl,--warn-common
+                                -Wl,-Map,${CMAKE_CURRENT_BINARY_DIR}/${target_name}.map -nostdlib
+                                )
+        add_custom_target(${target_name}.artifacts ALL
+                COMMAND ${CMAKE_OBJCOPY} -S -O ihex ${target_name}.elf ${target_name}.hex
+                COMMAND ${CMAKE_OBJCOPY} -S -O binary --only-section=.text ${target_name}.elf ${target_name}.bin
+                COMMAND ${CMAKE_OBJDUMP} -hS ${target_name}.elf > ${target_name}.lss
+                COMMAND ${CMAKE_SIZE} ${target_name}.elf
+                )
+        add_dependencies(${target_name}.artifacts ${target_name})
+        add_custom_target(${target_name}.flash
+                COMMAND nrfjprog --chiperase --program ${target_name}.hex)
+        add_dependencies(${target_name}.flash ${target_name}.artifacts)
+    endfunction()
+else()
+
+    # When not building for embedded hardware, things become more simple
+    function(add_bluetoe_example target_name)
+        add_executable(${target_name} ${target_name}.cpp)
+
+        target_link_libraries(${target_name}
+            PRIVATE
+                bluetoe::bindings::${BINDING}
+                example_hal
+        )
+    endfunction()
+
+endif()
+
 add_bluetoe_example(blinky)
 add_bluetoe_example(thermometer)
 add_bluetoe_example(cycling_speed_and_cadence)
diff --git a/examples/blinky.cpp b/examples/blinky.cpp
index 69aa3ee4..04c868fe 100644
--- a/examples/blinky.cpp
+++ b/examples/blinky.cpp
@@ -1,17 +1,13 @@
 #include <bluetoe/server.hpp>
 #include <bluetoe/device.hpp>
-#include <nrf.h>
+#include "hal/io.hpp"
 
 using namespace bluetoe;
 
-static constexpr int io_pin = 21;
-
 static std::uint8_t io_pin_write_handler( bool state )
 {
     // the GPIO pin according to the received value: 0 = off, 1 = on
-    NRF_GPIO->OUT = state
-        ? NRF_GPIO->OUT | ( 1 << io_pin )
-        : NRF_GPIO->OUT & ~( 1 << io_pin );
+    set_led( state );
 
     return error_codes::success;
 }
@@ -31,10 +27,7 @@ device< blinky_server > gatt_srv;
 
 int main()
 {
-    // Init GPIO pin
-    NRF_GPIO->PIN_CNF[ io_pin ] =
-        ( GPIO_PIN_CNF_DRIVE_S0H1 << GPIO_PIN_CNF_DRIVE_Pos ) |
-        ( GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos );
+    init_led();
 
     for ( ;; )
         gatt_srv.run( gatt );
diff --git a/examples/hal/CMakeLists.txt b/examples/hal/CMakeLists.txt
new file mode 100644
index 00000000..79ae09cf
--- /dev/null
+++ b/examples/hal/CMakeLists.txt
@@ -0,0 +1,13 @@
+cmake_policy(SET CMP0079 NEW)
+
+
+if (CMAKE_CROSSCOMPILING)
+    add_library(example_hal STATIC ${BINDING}_io.cpp)
+
+    # to get the required include path
+    target_link_libraries(example_hal PRIVATE toolchain::${BINDING})
+else()
+    add_library(example_hal STATIC io.cpp)
+endif()
+
+target_include_directories(example_hal PUBLIC ..)
\ No newline at end of file
diff --git a/examples/hal/io.cpp b/examples/hal/io.cpp
new file mode 100644
index 00000000..751a030c
--- /dev/null
+++ b/examples/hal/io.cpp
@@ -0,0 +1,13 @@
+#include "hal/io.hpp"
+#include <iostream>
+
+void init_led()
+{
+    std::cout << "init_led()" << std::endl;
+}
+
+void set_led( bool state )
+{
+    std::cout << "LED: " << ( state ? "on" : "off" ) << std::endl;
+}
+
diff --git a/examples/hal/io.hpp b/examples/hal/io.hpp
new file mode 100644
index 00000000..d0ab21d4
--- /dev/null
+++ b/examples/hal/io.hpp
@@ -0,0 +1,10 @@
+#ifndef BLUETOE_EXAMPLES_HAL_IO_HPP
+#define BLUETOE_EXAMPLES_HAL_IO_HPP
+
+/**
+ * @TODO this needs some more work (but not to much!!!)
+ */
+void init_led();
+void set_led( bool state );
+
+#endif
diff --git a/examples/hal/nrf51_io.cpp b/examples/hal/nrf51_io.cpp
new file mode 100644
index 00000000..6bf3e9b0
--- /dev/null
+++ b/examples/hal/nrf51_io.cpp
@@ -0,0 +1,19 @@
+#include <hal/io.hpp>
+#include <nrf.h>
+
+static constexpr int io_pin = 21;
+
+void init_led()
+{
+    // Init GPIO pin
+    NRF_GPIO->PIN_CNF[ io_pin ] =
+        ( GPIO_PIN_CNF_DRIVE_S0H1 << GPIO_PIN_CNF_DRIVE_Pos ) |
+        ( GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos );
+}
+
+void set_led( bool state )
+{
+    NRF_GPIO->OUT = state
+        ? NRF_GPIO->OUT | ( 1 << io_pin )
+        : NRF_GPIO->OUT & ~( 1 << io_pin );
+}
diff --git a/examples/hal/nrf52_io.cpp b/examples/hal/nrf52_io.cpp
new file mode 100644
index 00000000..dd58f0d7
--- /dev/null
+++ b/examples/hal/nrf52_io.cpp
@@ -0,0 +1 @@
+#include "nrf51.cpp"
\ No newline at end of file
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 7d26d8d9..4f038f24 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -13,7 +13,15 @@ function(add_and_register_test test_runner)
     add_executable(${test_runner} ${test_runner}.cpp)
 
     target_include_directories(${test_runner} PRIVATE ${Boost_INCLUDE_DIR})
-    target_link_libraries(${test_runner} PRIVATE bluetoe::iface bluetoe::linklayer bluetoe::sm bluetoe::utility test::tools)
+    target_link_libraries(${test_runner}
+        PRIVATE
+            bluetoe::iface
+            bluetoe::linklayer
+            bluetoe::sm
+            bluetoe::utility
+            test::tools
+            ${ARGN}
+    )
     target_compile_features(${test_runner} PRIVATE cxx_std_11)
 
     if (BLUETOE_EXCLUDE_SLOW_TESTS)
@@ -44,3 +52,4 @@ add_subdirectory(att)
 add_subdirectory(link_layer)
 add_subdirectory(services)
 add_subdirectory(security_manager)
+add_subdirectory(scheduled_radio)
diff --git a/tests/link_layer/CMakeLists.txt b/tests/link_layer/CMakeLists.txt
index 18e78d17..a9f717d1 100644
--- a/tests/link_layer/CMakeLists.txt
+++ b/tests/link_layer/CMakeLists.txt
@@ -1,17 +1,6 @@
-add_and_register_test(ll_advertising_tests)
 add_and_register_test(address_tests)
 add_and_register_test(channel_map_tests)
 add_and_register_test(delta_time_tests)
-add_and_register_test(ll_data_pdu_buffer_tests)
-add_and_register_test(ll_connection_tests)
-add_and_register_test(ll_connecting_tests)
-add_and_register_test(ll_control_tests)
-add_and_register_test(ll_data_tests)
-add_and_register_test(ring_buffer_tests)
 add_and_register_test(notification_queue_tests)
-add_and_register_test(connection_callbacks_tests)
 add_and_register_test(signaling_channel_tests)
 add_and_register_test(white_list_tests)
-add_and_register_test(connection_parameter_update_procedure_tests)
-add_and_register_test(test_radio_tests)
-add_and_register_test(advertiser_tests)
diff --git a/tests/scheduled_radio/CMakeLists.txt b/tests/scheduled_radio/CMakeLists.txt
new file mode 100644
index 00000000..48adb7f7
--- /dev/null
+++ b/tests/scheduled_radio/CMakeLists.txt
@@ -0,0 +1,15 @@
+function(add_and_register_ll_test name)
+    add_and_register_test(${name} bluetoe::scheduled_radio)
+endfunction()
+
+add_and_register_ll_test(ll_advertising_tests)
+add_and_register_ll_test(ll_data_pdu_buffer_tests)
+add_and_register_ll_test(ll_connection_tests)
+add_and_register_ll_test(ll_connecting_tests)
+add_and_register_ll_test(ll_control_tests)
+add_and_register_ll_test(ll_data_tests)
+add_and_register_ll_test(ring_buffer_tests)
+add_and_register_ll_test(connection_callbacks_tests)
+add_and_register_ll_test(connection_parameter_update_procedure_tests)
+add_and_register_ll_test(test_radio_tests)
+add_and_register_ll_test(advertiser_tests)
diff --git a/tests/link_layer/advertiser_tests.cpp b/tests/scheduled_radio/advertiser_tests.cpp
similarity index 100%
rename from tests/link_layer/advertiser_tests.cpp
rename to tests/scheduled_radio/advertiser_tests.cpp
diff --git a/tests/link_layer/connected.hpp b/tests/scheduled_radio/connected.hpp
similarity index 100%
rename from tests/link_layer/connected.hpp
rename to tests/scheduled_radio/connected.hpp
diff --git a/tests/link_layer/connection_callbacks_tests.cpp b/tests/scheduled_radio/connection_callbacks_tests.cpp
similarity index 100%
rename from tests/link_layer/connection_callbacks_tests.cpp
rename to tests/scheduled_radio/connection_callbacks_tests.cpp
diff --git a/tests/link_layer/connection_parameter_update_procedure_tests.cpp b/tests/scheduled_radio/connection_parameter_update_procedure_tests.cpp
similarity index 100%
rename from tests/link_layer/connection_parameter_update_procedure_tests.cpp
rename to tests/scheduled_radio/connection_parameter_update_procedure_tests.cpp
diff --git a/tests/link_layer/ll_advertising_tests.cpp b/tests/scheduled_radio/ll_advertising_tests.cpp
similarity index 100%
rename from tests/link_layer/ll_advertising_tests.cpp
rename to tests/scheduled_radio/ll_advertising_tests.cpp
diff --git a/tests/link_layer/ll_connecting_tests.cpp b/tests/scheduled_radio/ll_connecting_tests.cpp
similarity index 100%
rename from tests/link_layer/ll_connecting_tests.cpp
rename to tests/scheduled_radio/ll_connecting_tests.cpp
diff --git a/tests/link_layer/ll_connection_tests.cpp b/tests/scheduled_radio/ll_connection_tests.cpp
similarity index 100%
rename from tests/link_layer/ll_connection_tests.cpp
rename to tests/scheduled_radio/ll_connection_tests.cpp
diff --git a/tests/link_layer/ll_control_tests.cpp b/tests/scheduled_radio/ll_control_tests.cpp
similarity index 100%
rename from tests/link_layer/ll_control_tests.cpp
rename to tests/scheduled_radio/ll_control_tests.cpp
diff --git a/tests/link_layer/ll_data_pdu_buffer_tests.cpp b/tests/scheduled_radio/ll_data_pdu_buffer_tests.cpp
similarity index 100%
rename from tests/link_layer/ll_data_pdu_buffer_tests.cpp
rename to tests/scheduled_radio/ll_data_pdu_buffer_tests.cpp
diff --git a/tests/link_layer/ll_data_tests.cpp b/tests/scheduled_radio/ll_data_tests.cpp
similarity index 100%
rename from tests/link_layer/ll_data_tests.cpp
rename to tests/scheduled_radio/ll_data_tests.cpp
diff --git a/tests/link_layer/ring_buffer_tests.cpp b/tests/scheduled_radio/ring_buffer_tests.cpp
similarity index 100%
rename from tests/link_layer/ring_buffer_tests.cpp
rename to tests/scheduled_radio/ring_buffer_tests.cpp
diff --git a/tests/link_layer/test_radio_tests.cpp b/tests/scheduled_radio/test_radio_tests.cpp
similarity index 100%
rename from tests/link_layer/test_radio_tests.cpp
rename to tests/scheduled_radio/test_radio_tests.cpp
diff --git a/tests/test_tools/CMakeLists.txt b/tests/test_tools/CMakeLists.txt
index 9f81531b..b486074b 100644
--- a/tests/test_tools/CMakeLists.txt
+++ b/tests/test_tools/CMakeLists.txt
@@ -11,7 +11,7 @@ add_library(test::tools ALIAS test_tools)
 
 target_include_directories(test_tools PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_include_directories(test_tools PRIVATE ${Boost_INCLUDE_DIR})
-target_link_libraries(test_tools PRIVATE bluetoe::linklayer)
+target_link_libraries(test_tools PRIVATE bluetoe::linklayer bluetoe::scheduled_radio)
 target_compile_features(test_tools PRIVATE cxx_std_11)
 target_compile_definitions(test_tools PRIVATE "")