diff --git a/source/test/src/_initialize_hardware.c b/source/firmware/arch/stm32f4xx/_initialize_hardware.c
similarity index 100%
rename from source/test/src/_initialize_hardware.c
rename to source/firmware/arch/stm32f4xx/_initialize_hardware.c
diff --git a/source/test/src/_write.c b/source/firmware/arch/stm32f4xx/_write.c
similarity index 100%
rename from source/test/src/_write.c
rename to source/firmware/arch/stm32f4xx/_write.c
diff --git a/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/include/stm32f4-discovery.h b/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/include/stm32f4-discovery.h
index 01260a3..e290263 100755
--- a/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/include/stm32f4-discovery.h
+++ b/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/include/stm32f4-discovery.h
@@ -9,16 +9,18 @@
 #include <stddef.h>
 #include <stdint.h>
 #if 0
-#include "../../../../../kernel/include/sys_tick.h"
-#include "../../../driver/include/stm32_sys_tick.h"
 #include "../../../driver/include/stm32f4_pwm.h"
 #include "../../../driver/include/stm32f4_uart.h"
 #include "pwm.h"
-#include "timer.h"
 #include "uart.h"
 #include "ringbuffer.h"
 #endif
 #include "stm32f4xx.h"
+
+#include "timer.h"
+#include "stm32_sys_tick.h"
+#include "sys_tick.h"
+
 #include "gpio.h"
 #include "stm32f4_gpio.h"
 #include "driver.h"
@@ -41,27 +43,27 @@ static const struct gpio __gpio_d12 = {
 		&gpio_fp
 };
 
-const struct driver gpio_d12 = {
+static const struct driver gpio_d12 = {
 		DRIVER_TYPE_GPIO,
 		&__gpio_d12,
 };
 
 
-#if 0
 // SYSTEM TICK
 static const enum stm32_sys_tick_time_base stm23_sys_tick_time_base =
 		STM32_SYS_TICK_TIME_BASE_MS;
+
 static const struct stm32_sys_tick stm32_sys_tick = {
-		&stm23_sys_tick_time_base,
-		NULL,
-		NULL
+		.tick_time_base = &stm23_sys_tick_time_base,
+		.sys_tick_cb = NULL,
+		.sys_tick_cb_param = NULL,
 };
 
 static const struct loki_timer timer_1 = {
-		(void*)&stm32_sys_tick,
-		&timer_fp
+		.arch_dep_device = (void*)&stm32_sys_tick,
+		.fp = &timer_fp
 };
-#endif
+
 #if 0
 // PWM CHANNEL 4
 /* apb1 clock = 84MHz */
diff --git a/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/stm32f4-discovery.c b/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/stm32f4-discovery.c
index 9c0e390..15908f6 100755
--- a/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/stm32f4-discovery.c
+++ b/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/stm32f4-discovery.c
@@ -7,10 +7,12 @@
 
 #include "board.h"
 
-void board_init(void) {
+void board_init(void)
+{
+#if 0
 	NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0);
 	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);
 	SysTick_CLKSourceConfig(RCC_SYSCLKSource_PLLCLK);
-
+#endif
 	sys_tick_init(&timer_1);
 }
diff --git a/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/stm32f4-discovery.mk b/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/stm32f4-discovery.mk
index 5ee2e64..52f3b9c 100755
--- a/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/stm32f4-discovery.mk
+++ b/source/firmware/arch/stm32f4xx/board/stm32f4-discovery/stm32f4-discovery.mk
@@ -1,4 +1,2 @@
-CHECK_FOLDER += source/firmware/arch/stm32f4xx/board/stm32f4-discovery
-SUB_FOLDER += source/firmware/arch/stm32f4xx/board/stm32f4-discovery
+SRC_DIR += source/firmware/arch/stm32f4xx/board/stm32f4-discovery
 INCLUDES += source/firmware/arch/stm32f4xx/board/stm32f4-discovery/include
-DOC_SRC += source/firmware/arch/stm32f4xx/board/stm32f4-discovery
\ No newline at end of file
diff --git a/source/firmware/arch/stm32f4xx/driver/include/stm32_sys_tick.h b/source/firmware/arch/stm32f4xx/driver/include/stm32_sys_tick.h
new file mode 100644
index 0000000..a1864fc
--- /dev/null
+++ b/source/firmware/arch/stm32f4xx/driver/include/stm32_sys_tick.h
@@ -0,0 +1,47 @@
+//! \file stm32_sys_tick.h
+//! \author tkl
+//! \date Feb 15, 2012
+//! \brief Header file of the stm32f10x architecture dependent sys tick timer implementation.
+#ifndef STM32_SYS_TICK_H_
+#define STM32_SYS_TICK_H_
+
+typedef void* (*stm32_sys_tick_cb_t)(void*);	//!< callback for the external interrupt
+
+//! \brief Type of sys tick base time.
+enum stm32_sys_tick_time_base {
+	STM32_SYS_TICK_TIME_BASE_NONE = 0,	//!< Not init
+	STM32_SYS_TICK_TIME_BASE_US,		//!< Tick time = 1 us.
+	STM32_SYS_TICK_TIME_BASE_MS			//!< Tick time = 1 ms.
+};
+
+//! \brief The sys tick device.
+struct stm32_sys_tick {
+	const enum stm32_sys_tick_time_base *tick_time_base;	//!< time base for the system tick
+	stm32_sys_tick_cb_t sys_tick_cb;					//!< callback for the sys tick interrupt
+	void *sys_tick_cb_param;							//!< parameter for the callback
+};
+
+//! \brief Open a sys tick timer.
+//! \param sys_tick The sys tick to open. Must be of type const stm32_sys_tick_t*.
+//! \return -1 in error case.
+int stm32_sys_tick_open(const void *sys_tick);
+
+//! \brief Close a sys tick timer.
+//! \param sys_tick The sys tick to close. Must be of type const stm32_sys_tick_t*.
+//! \return -1 in error case.
+int stm32_sys_tick_close(const void *sys_tick);
+
+//! \brief Set the call back for a sys tick timer.
+//! \param sys_tick The sys tick to open. Mus be of type const stm32_sys_tick_t*.
+//! \param callback The function pointer of the call back function.
+//! \param param The parameter for the call back function.
+//! \return -1 in error case.
+int stm32_sys_tick_set_cb(const void *sys_tick, const void *callback, const void *param);
+
+static const struct timer_fp timer_fp = {
+		stm32_sys_tick_open,
+		stm32_sys_tick_close,
+		stm32_sys_tick_set_cb
+};
+
+#endif /* STM32_SYS_TICK_H_ */
diff --git a/source/firmware/arch/stm32f4xx/driver/stm32_sys_tick._c b/source/firmware/arch/stm32f4xx/driver/stm32_sys_tick.c
similarity index 98%
rename from source/firmware/arch/stm32f4xx/driver/stm32_sys_tick._c
rename to source/firmware/arch/stm32f4xx/driver/stm32_sys_tick.c
index 209a097..4d00ec7 100755
--- a/source/firmware/arch/stm32f4xx/driver/stm32_sys_tick._c
+++ b/source/firmware/arch/stm32f4xx/driver/stm32_sys_tick.c
@@ -8,6 +8,7 @@
 
 #include "stm32f4xx.h"
 
+#include "timer.h"
 #include "stm32_sys_tick.h"
 #include "stm32f4xx_isr.h"
 
diff --git a/source/test/src/stm32f4xx_hal_msp.c b/source/firmware/arch/stm32f4xx/stm32f4xx_hal_msp.c
similarity index 100%
rename from source/test/src/stm32f4xx_hal_msp.c
rename to source/firmware/arch/stm32f4xx/stm32f4xx_hal_msp.c
diff --git a/source/firmware/kernel/driver/timer.c b/source/firmware/kernel/driver/timer.c
index 28f4583..c0ec760 100755
--- a/source/firmware/kernel/driver/timer.c
+++ b/source/firmware/kernel/driver/timer.c
@@ -2,9 +2,10 @@
 //! \author tkl
 //! \date Jul 5, 2012
 //! \brief Source file of the architecture independent timer implementation.
+#include "include/timer.h"
+
 #include <stddef.h>
 
-#include "timer.h"
 
 int timer_open(const struct loki_timer *device)
 {
diff --git a/source/firmware/kernel/include/sys_tick.h b/source/firmware/kernel/include/sys_tick.h
index 2a6d94f..31e15bf 100644
--- a/source/firmware/kernel/include/sys_tick.h
+++ b/source/firmware/kernel/include/sys_tick.h
@@ -8,6 +8,6 @@
 #ifndef SYS_TICK_H_
 #define SYS_TICK_H_
 
-//void sys_tick_init(const struct loki_timer *hw_timer);
+void sys_tick_init(const struct loki_timer *hw_timer);
 
 #endif /* SYS_TICK_H_ */
diff --git a/source/firmware/kernel/sys_tick.c b/source/firmware/kernel/sys_tick.c
index c3ec040..e5f7bc2 100644
--- a/source/firmware/kernel/sys_tick.c
+++ b/source/firmware/kernel/sys_tick.c
@@ -4,13 +4,12 @@
  *  Created on: Sep 25, 2015
  *      Author: tkl
  */
-#include "include/sys_tick.h"
-
 #include <stddef.h>
 #include <stdbool.h>
 
-#include "irq.h"
 #include "timer.h"
+#include "sys_tick.h"
+#include "irq.h"
 #include "stack.h"
 #include "queue.h"
 #include "thread.h"
diff --git a/source/test/src/BlinkLed.c b/source/test/src/BlinkLed.c
deleted file mode 100644
index dae01d7..0000000
--- a/source/test/src/BlinkLed.c
+++ /dev/null
@@ -1,29 +0,0 @@
-//
-// This file is part of the GNU ARM Eclipse distribution.
-// Copyright (c) 2014 Liviu Ionescu.
-//
-
-#include "BlinkLed.h"
-
-// ----------------------------------------------------------------------------
-
-void
-blink_led_init()
-{
-  // Enable GPIO Peripheral clock
-  RCC->AHB1ENR |= BLINK_RCC_MASKx(BLINK_PORT_NUMBER);
-
-  GPIO_InitTypeDef GPIO_InitStructure;
-
-  // Configure pin in output push/pull mode
-  GPIO_InitStructure.Pin = BLINK_PIN_MASK(BLINK_PIN_NUMBER);
-  GPIO_InitStructure.Mode = GPIO_MODE_OUTPUT_PP;
-  GPIO_InitStructure.Speed = GPIO_SPEED_FAST;
-  GPIO_InitStructure.Pull = GPIO_PULLUP;
-  HAL_GPIO_Init(BLINK_GPIOx(BLINK_PORT_NUMBER), &GPIO_InitStructure);
-
-  // Start with led turned off
-  blink_led_off();
-}
-
-// ----------------------------------------------------------------------------
diff --git a/source/test/src/Timer.c b/source/test/src/Timer.c
deleted file mode 100644
index 109f9be..0000000
--- a/source/test/src/Timer.c
+++ /dev/null
@@ -1,64 +0,0 @@
-//
-// This file is part of the GNU ARM Eclipse distribution.
-// Copyright (c) 2014 Liviu Ionescu.
-//
-
-#include "Timer.h"
-#include "cortexm/ExceptionHandlers.h"
-
-// ----------------------------------------------------------------------------
-
-#if defined(USE_HAL_DRIVER)
-void HAL_IncTick(void);
-#endif
-
-// Forward declarations.
-
-void
-timer_tick (void);
-
-// ----------------------------------------------------------------------------
-
-volatile timer_ticks_t timer_delayCount;
-
-// ----------------------------------------------------------------------------
-
-void
-timer_start (void)
-{
-  // Use SysTick as reference for the delay loops.
-  SysTick_Config (SystemCoreClock / TIMER_FREQUENCY_HZ);
-}
-
-void
-timer_sleep (timer_ticks_t ticks)
-{
-  timer_delayCount = ticks;
-
-  // Busy wait until the SysTick decrements the counter to zero.
-  while (timer_delayCount != 0u)
-    ;
-}
-
-void
-timer_tick (void)
-{
-  // Decrement to zero the counter used by the delay routine.
-  if (timer_delayCount != 0u)
-    {
-      --timer_delayCount;
-    }
-}
-
-// ----- SysTick_Handler() ----------------------------------------------------
-
-void
-SysTick_Handler (void)
-{
-#if defined(USE_HAL_DRIVER)
-  HAL_IncTick();
-#endif
-  timer_tick ();
-}
-
-// ----------------------------------------------------------------------------
diff --git a/source/test/src/include/BlinkLed.h b/source/test/src/include/BlinkLed.h
deleted file mode 100644
index b82bc88..0000000
--- a/source/test/src/include/BlinkLed.h
+++ /dev/null
@@ -1,84 +0,0 @@
-//
-// This file is part of the GNU ARM Eclipse distribution.
-// Copyright (c) 2014 Liviu Ionescu.
-//
-
-#ifndef BLINKLED_H_
-#define BLINKLED_H_
-
-#include "stm32f4xx.h"
-#include "stm32f4xx_hal.h"
-
-// ----- LED definitions ------------------------------------------------------
-
-// Adjust these definitions for your own board.
-
-#if defined(BOARD_OLIMEX_STM32_E407)
-
-// STM32-E407 definitions (the GREEN led, C13, active low)
-
-// Port numbers: 0=A, 1=B, 2=C, 3=D, 4=E, 5=F, 6=G, ...
-#define BLINK_PORT_NUMBER               (2)
-#define BLINK_PIN_NUMBER                (13)
-#define BLINK_ACTIVE_LOW                (1)
-
-#else
-
-// STM32F4DISCOVERY definitions (the GREEN led, D12, active high)
-// (SEGGER J-Link device name: STM32F407VG).
-
-#define BLINK_PORT_NUMBER               (3)
-#define BLINK_PIN_NUMBER                (12)
-#define BLINK_ACTIVE_LOW                (0)
-
-#endif
-
-#define BLINK_GPIOx(_N)                 ((GPIO_TypeDef *)(GPIOA_BASE + (GPIOB_BASE-GPIOA_BASE)*(_N)))
-#define BLINK_PIN_MASK(_N)              (1 << (_N))
-#define BLINK_RCC_MASKx(_N)             (RCC_AHB1ENR_GPIOAEN << (_N))
-
-// ----------------------------------------------------------------------------
-
-extern
-void
-blink_led_init(void);
-
-// ----------------------------------------------------------------------------
-
-inline void
-blink_led_on(void);
-
-inline void
-blink_led_off(void);
-
-// ----------------------------------------------------------------------------
-
-inline void
-__attribute__((always_inline))
-blink_led_on(void)
-{
-#if (BLINK_ACTIVE_LOW)
-    HAL_GPIO_WritePin(BLINK_GPIOx(BLINK_PORT_NUMBER),
-        BLINK_PIN_MASK(BLINK_PIN_NUMBER), GPIO_PIN_RESET);
-#else
-    HAL_GPIO_WritePin(BLINK_GPIOx(BLINK_PORT_NUMBER),
-        BLINK_PIN_MASK(BLINK_PIN_NUMBER), GPIO_PIN_SET);
-#endif
-}
-
-inline void
-__attribute__((always_inline))
-blink_led_off(void)
-{
-#if (BLINK_ACTIVE_LOW)
-    HAL_GPIO_WritePin(BLINK_GPIOx(BLINK_PORT_NUMBER),
-        BLINK_PIN_MASK(BLINK_PIN_NUMBER), GPIO_PIN_SET);
-#else
-    HAL_GPIO_WritePin(BLINK_GPIOx(BLINK_PORT_NUMBER),
-        BLINK_PIN_MASK(BLINK_PIN_NUMBER), GPIO_PIN_RESET);
-#endif
-}
-
-// ----------------------------------------------------------------------------
-
-#endif // BLINKLED_H_
diff --git a/source/test/src/include/Timer.h b/source/test/src/include/Timer.h
deleted file mode 100644
index 9ff2085..0000000
--- a/source/test/src/include/Timer.h
+++ /dev/null
@@ -1,27 +0,0 @@
-//
-// This file is part of the GNU ARM Eclipse distribution.
-// Copyright (c) 2014 Liviu Ionescu.
-//
-
-#ifndef TIMER_H_
-#define TIMER_H_
-
-#include "cmsis_device.h"
-
-// ----------------------------------------------------------------------------
-
-#define TIMER_FREQUENCY_HZ (1000u)
-
-typedef uint32_t timer_ticks_t;
-
-extern volatile timer_ticks_t timer_delayCount;
-
-extern void
-timer_start (void);
-
-extern void
-timer_sleep (timer_ticks_t ticks);
-
-// ----------------------------------------------------------------------------
-
-#endif // TIMER_H_
diff --git a/source/test/src/include/include.mk b/source/test/src/include/include.mk
deleted file mode 100644
index 4c58a42..0000000
--- a/source/test/src/include/include.mk
+++ /dev/null
@@ -1 +0,0 @@
-INCLUDES += include
diff --git a/source/test/src/main.c b/source/test/src/main.c
index 1cf1eba..d959f86 100644
--- a/source/test/src/main.c
+++ b/source/test/src/main.c
@@ -3,20 +3,16 @@
 // Copyright (c) 2014 Liviu Ionescu.
 //
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include "diag/Trace.h"
-
-#include "Timer.h"
-#include "BlinkLed.h"
 
+#include "stack.h"
+#include "queue.h"
+#include "kernel.h"
 #include "board.h"
 #include "driver.h"
 
-// Keep the LED on for 2/3 of a second.
-#define BLINK_ON_TICKS  (TIMER_FREQUENCY_HZ * 3 / 4)
-#define BLINK_OFF_TICKS (TIMER_FREQUENCY_HZ - BLINK_ON_TICKS)
-
 // Sample pragmas to cope with warnings. Please note the related line at
 // the end of this function, used to pop the compiler diagnostics status.
 #pragma GCC diagnostic push
@@ -24,25 +20,30 @@
 #pragma GCC diagnostic ignored "-Wmissing-declarations"
 #pragma GCC diagnostic ignored "-Wreturn-type"
 
-int main(int argc, char* argv[])
+#define TH_STACK_SIZE  256
+stack_t th_stack[TH_STACK_SIZE];
+struct thread_context th_ctx;
+static void th_func(void *arg)
 {
-	trace_puts("Hello ARM World!");
-	trace_printf("System clock: %u Hz\n", SystemCoreClock);
-	timer_start();
-//	blink_led_init();
-	uint32_t seconds = 0;
 	drv_open(&gpio_d12);
-	drv_write(&gpio_d12, "1", 1);
+	drv_write(&gpio_d12, "0", 1);
 	while(1) {
-//		blink_led_on();
+		sleep_ms(1000);
 		drv_write(&gpio_d12, "1", 1);
-		timer_sleep(seconds == 0 ? TIMER_FREQUENCY_HZ : BLINK_ON_TICKS);
-//		blink_led_off();
+		sleep_ms(1000);
 		drv_write(&gpio_d12, "0", 1);
-		timer_sleep(BLINK_OFF_TICKS);
-		++seconds;
-		trace_printf("Second %u\n", seconds);
 	}
 }
 
+
+int main(int argc, char* argv[])
+{
+	board_init();
+	thread_create(&th_ctx, th_stack, TH_STACK_SIZE, th_func, NULL, THREAD_PRIO_LOW);
+
+	schedule_start();
+
+	return 0;
+}
+
 #pragma GCC diagnostic pop