IO operation methods

LCD RAM functions. More...

Functions
HAL_StatusTypeDef	HAL_LCD_Write (LCD_HandleTypeDef *hlcd, uint32_t RAMRegisterIndex, uint32_t RAMRegisterMask, uint32_t Data)
	Write a word in the specific LCD RAM. More...
HAL_StatusTypeDef	HAL_LCD_Clear (LCD_HandleTypeDef *hlcd)
	Clear the LCD RAM registers. More...
HAL_StatusTypeDef	HAL_LCD_UpdateDisplayRequest (LCD_HandleTypeDef *hlcd)
	Enable the Update Display Request. More...

Detailed Description

LCD RAM functions.

 ===============================================================================
                      ##### IO operation functions #####
 ===============================================================================
 [..] Using its double buffer memory the LCD controller ensures the coherency of the
 displayed information without having to use interrupts to control LCD_RAM
 modification.
 The application software can access the first buffer level (LCD_RAM) through
 the APB interface. Once it has modified the LCD_RAM using the HAL_LCD_Write() API,
 it sets the UDR flag in the LCD_SR register using the HAL_LCD_UpdateDisplayRequest() API.
 This UDR flag (update display request) requests the updated information to be
 moved into the second buffer level (LCD_DISPLAY).
 This operation is done synchronously with the frame (at the beginning of the
 next frame), until the update is completed, the LCD_RAM is write protected and
 the UDR flag stays high.
 Once the update is completed another flag (UDD - Update Display Done) is set and
 generates an interrupt if the UDDIE bit in the LCD_FCR register is set.
 The time it takes to update LCD_DISPLAY is, in the worst case, one odd and one
 even frame.
 The update will not occur (UDR = 1 and UDD = 0) until the display is
 enabled (LCDEN = 1).

Function Documentation

HAL_LCD_Clear()

HAL_StatusTypeDef HAL_LCD_Clear

(

LCD_HandleTypeDef *

hlcd

)

Clear the LCD RAM registers.

Parameters

hlcd	LCD handle

Return values

None

< Wait Until the LCD is ready

Definition at line 425 of file stm32l4xx_hal_lcd.c.

{
  uint32_t tickstart;
  uint32_t counter;
  HAL_StatusTypeDef status = HAL_ERROR;
  HAL_LCD_StateTypeDef state = hlcd->State;
  
  if ((state == HAL_LCD_STATE_READY) || (state == HAL_LCD_STATE_BUSY))
  {
    /* Process Locked */
    __HAL_LOCK(hlcd);

    hlcd->State = HAL_LCD_STATE_BUSY;

    /* Get timeout */
    tickstart = HAL_GetTick();

    while (__HAL_LCD_GET_FLAG(hlcd, LCD_FLAG_UDR) != RESET)
    {
      if ((HAL_GetTick() - tickstart) > LCD_TIMEOUT_VALUE)
      {
        hlcd->ErrorCode = HAL_LCD_ERROR_UDR;

        /* Process Unlocked */
        __HAL_UNLOCK(hlcd);

        return HAL_TIMEOUT;
      }
    }
    /* Clear the LCD_RAM registers */
    for (counter = LCD_RAM_REGISTER0; counter <= LCD_RAM_REGISTER15; counter++)
    {
      hlcd->Instance->RAM[counter] = 0;
    }

    /* Update the LCD display */
    status = HAL_LCD_UpdateDisplayRequest(hlcd);
  }
  return status;
}

HAL_LCD_UpdateDisplayRequest()

HAL_StatusTypeDef HAL_LCD_UpdateDisplayRequest

(

LCD_HandleTypeDef *

hlcd

)

Enable the Update Display Request.

Parameters

hlcd	LCD handle

Note

Each time software modifies the LCD_RAM it must set the UDR bit to transfer the updated data to the second level buffer. The UDR bit stays set until the end of the update and during this time the LCD_RAM is write protected.

When the display is disabled, the update is performed for all LCD_DISPLAY locations. When the display is enabled, the update is performed only for locations for which commons are active (depending on DUTY). For example if DUTY = 1/2, only the LCD_DISPLAY of COM0 and COM1 will be updated.

Return values

None

< Wait Until the LCD display is done

Definition at line 481 of file stm32l4xx_hal_lcd.c.

{
  uint32_t tickstart;

  /* Clear the Update Display Done flag before starting the update display request */
  __HAL_LCD_CLEAR_FLAG(hlcd, LCD_FLAG_UDD);

  /* Enable the display request */
  hlcd->Instance->SR |= LCD_SR_UDR;

  /* Get timeout */
  tickstart = HAL_GetTick();

  while (__HAL_LCD_GET_FLAG(hlcd, LCD_FLAG_UDD) == RESET)
  {
    if ((HAL_GetTick() - tickstart) > LCD_TIMEOUT_VALUE)
    {
      hlcd->ErrorCode = HAL_LCD_ERROR_UDD;

      /* Process Unlocked */
      __HAL_UNLOCK(hlcd);

      return HAL_TIMEOUT;
    }
  }

  hlcd->State = HAL_LCD_STATE_READY;

  /* Process Unlocked */
  __HAL_UNLOCK(hlcd);

  return HAL_OK;
}

HAL_LCD_Write()

HAL_StatusTypeDef HAL_LCD_Write	(	LCD_HandleTypeDef *	hlcd,
		uint32_t	RAMRegisterIndex,
		uint32_t	RAMRegisterMask,
		uint32_t	Data
	)

Write a word in the specific LCD RAM.

Parameters

hlcd	LCD handle
RAMRegisterIndex	specifies the LCD RAM Register. This parameter can be one of the following values: LCD_RAM_REGISTER0: LCD RAM Register 0 LCD_RAM_REGISTER1: LCD RAM Register 1 LCD_RAM_REGISTER2: LCD RAM Register 2 LCD_RAM_REGISTER3: LCD RAM Register 3 LCD_RAM_REGISTER4: LCD RAM Register 4 LCD_RAM_REGISTER5: LCD RAM Register 5 LCD_RAM_REGISTER6: LCD RAM Register 6 LCD_RAM_REGISTER7: LCD RAM Register 7 LCD_RAM_REGISTER8: LCD RAM Register 8 LCD_RAM_REGISTER9: LCD RAM Register 9 LCD_RAM_REGISTER10: LCD RAM Register 10 LCD_RAM_REGISTER11: LCD RAM Register 11 LCD_RAM_REGISTER12: LCD RAM Register 12 LCD_RAM_REGISTER13: LCD RAM Register 13 LCD_RAM_REGISTER14: LCD RAM Register 14 LCD_RAM_REGISTER15: LCD RAM Register 15
RAMRegisterMask	specifies the LCD RAM Register Data Mask.
Data	specifies LCD Data Value to be written.

Return values

None

< Wait Until the LCD is ready

Definition at line 375 of file stm32l4xx_hal_lcd.c.

{
  uint32_t tickstart;
  HAL_LCD_StateTypeDef state = hlcd->State;
  
  if ((state == HAL_LCD_STATE_READY) || (state == HAL_LCD_STATE_BUSY))
  {
    /* Check the parameters */
    assert_param(IS_LCD_RAM_REGISTER(RAMRegisterIndex));

    if (hlcd->State == HAL_LCD_STATE_READY)
    {
      /* Process Locked */
      __HAL_LOCK(hlcd);
      hlcd->State = HAL_LCD_STATE_BUSY;

      /* Get timeout */
      tickstart = HAL_GetTick();

      while (__HAL_LCD_GET_FLAG(hlcd, LCD_FLAG_UDR) != RESET)
      {
        if ((HAL_GetTick() - tickstart) > LCD_TIMEOUT_VALUE)
        {
          hlcd->ErrorCode = HAL_LCD_ERROR_UDR;

          /* Process Unlocked */
          __HAL_UNLOCK(hlcd);

          return HAL_TIMEOUT;
        }
      }
    }

    /* Copy the new Data bytes to LCD RAM register */
    MODIFY_REG(hlcd->Instance->RAM[RAMRegisterIndex], ~(RAMRegisterMask), Data);

    return HAL_OK;
  }
  else
  {
    return HAL_ERROR;
  }
}