STM32 undefined HAL symbol

Hi All,

I just started learning ARM and I got a STM32L0 Nucleo board with Keils uVision5 as the environment. I used STM32Cube to generate the start-up code and got a blinky example and a button external interrupt example working.

I'm trying to get a Timer Interrupt example working by following this tutorial:
lostwire.wordpress.com/.../

But I run into some definition problem, error as:

CubeProjectOne Configuration\CubeProjectOne Configuration.axf: Error: L6218E: Undefined symbol HAL_TIM_Base_Init (referred from main.o).
CubeProjectOne Configuration\CubeProjectOne Configuration.axf: Error: L6218E: Undefined symbol HAL_TIM_Base_Start_IT (referred from main.o).

I checked that HAL_TIM_Base_Init and HAL_TIM_Base_Start_IT are located in stm32l0xx_hal_tim.h line 1152, 1153 as:

HAL_StatusTypeDef HAL_TIM_Base_Init(TIM_HandleTypeDef *htim);
HAL_StatusTypeDef HAL_TIM_Base_DeInit(TIM_HandleTypeDef *htim);

But in stm32l0xx_hal_tim.h line 47 (47 #include "stm32l0xx_hal_def.h") there's a red cross and when I hover over it, it says "error in include chain stm32l0xx_hal_rcc_ex.h: unknown type name 'HAL_StatusTypeDef." that repeated for a whole bunch of different header files.

Then in file "stm32l0xx_hal_def.h", which is where HAL_StatusTypeDef is located, it has the same error "error in include chain stm32l0xx_hal_rcc_ex.h: unknown type name 'HAL_StatusTypeDef." at line 48 (48 #include "stm32l0xx.h").

I'm not sure if it's a linker problem, multiple definition or what, but I really can't figure out why.

Please see my main code as attached.

Thanks!

/* Includes ------------------------------------------------------------------*/
#include "stm32l0xx.h"
#include "stm32l0xx_hal.h"
#include "stm32l0xx_hal_tim.h"                // For TIM_HandleTypeDef


/* USER CODE BEGIN PV */
volatile uint32_t blink_period = 500;
TIM_HandleTypeDef TIM_Handle;

/* Set Up Timer --------------------------------------------------------------*/
void Timer_SetUp (void)
{
        // 1. Enable Timer
        __TIM2_CLK_ENABLE();

        // 2. set up to toggle at 500 ms
        TIM_Handle.Init.Prescaler = 15;
        TIM_Handle.Init.CounterMode = TIM_COUNTERMODE_UP;
        TIM_Handle.Init.Period = 62499;

        // 3. Specify HW timer to be used
        TIM_Handle.Instance = TIM2;

        // 4. Initialise and start interrupt
        HAL_TIM_Base_Init(&TIM_Handle);     // Init timer
        HAL_TIM_Base_Start_IT(&TIM_Handle); // start timer interrupts

        // 5. Unmask timer
        HAL_NVIC_SetPriority(TIM2_IRQn, 0, 1);
        HAL_NVIC_EnableIRQ(TIM2_IRQn);

}


/* Timer handler -------------------------------------------------------------*/
void TIM4_IRQHandler(void)
{
    __HAL_TIM_CLEAR_FLAG(&T2_Handle, TIM_FLAG_UPDATE);
    /*Some code here */

}

/** System Clock Configuration
*/
void SystemClock_Config(void)
{

  RCC_OscInitTypeDef RCC_OscInitStruct;
  RCC_ClkInitTypeDef RCC_ClkInitStruct;

  __PWR_CLK_ENABLE();

  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
  RCC_OscInitStruct.MSIState = RCC_MSI_ON;
  RCC_OscInitStruct.MSICalibrationValue = 0;
  RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_5;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  HAL_RCC_OscConfig(&RCC_OscInitStruct);

  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
  HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0);

  HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);

  HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

}