STM32F4 t6963 interfacing usage about u8g2 HOT 19 CLOSED

    case U8X8_MSG_GPIO_D1:				// D1 or SPI data pin: Output level in arg_int
		HAL_GPIO_WritePin(DATA_PORT, D0_Pin, arg_int);

 /* USER CODE BEGIN 2 */
  u8g2_Setup_t6963_240x64_f(&u8g2, U8G2_R0,u8x8_byte_8bit_8080mode, u8x8_stm32_gpio_and_delay);

  u8g2_InitDisplay(&u8g2);
  u8g2_SetPowerSave(&u8g2, 0);
	// clear VRAM
	for (int y=0;y<LCD_ys;y++)
		for (int x=0;x<LCD_xs>>3;x++)
			VRAM[y][x]=col0;

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
	while (1)
	{
		u8g2_ClearBuffer(&u8g2);

		u8g2_SetDrawColor(&u8g2,1);
		u8g2_DrawCircle(&u8g2, 20, 20, 20, U8G2_DRAW_ALL);
		u8g2_SetFont(&u8g2, u8g2_font_ncenB14_tr);
		u8g2_DrawStr(&u8g2, 0, 15, "Tarkan");

		for(int i = 0; i < 200; i++)
		{
			u8g2_DrawPixel(&u8g2, i, i);
		}
		u8g2_SendBuffer(&u8g2);

  __HAL_RCC_GPIOE_CLK_ENABLE();
   GPIO_InitStruct.Pin = GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5
                          |GPIO_PIN_6|GPIO_PIN_7|GPIO_PIN_8|GPIO_PIN_9
                          |GPIO_PIN_10|GPIO_PIN_11|GPIO_PIN_12|GPIO_PIN_0
                          |GPIO_PIN_1;

  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_MEDIUM;
  HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);

uint8_t u8x8_stm32_gpio_and_delay(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
{
	switch(msg)
	{
	case U8X8_MSG_GPIO_AND_DELAY_INIT:
		/* Insert codes for initialization */
		break;
	case U8X8_MSG_DELAY_10MICRO:
		for (uint16_t n = 0; n < 320; n++)
		{
			__NOP();
		}
		break;
	case U8X8_MSG_DELAY_NANO:
		delay_ns(arg_int);

		break;
	case U8X8_MSG_DELAY_100NANO:
		for(int i = 0; i < 100; i++)
		{
			delay_ns(1);
		}
		break;
	case U8X8_MSG_DELAY_MILLI:
		/* ms Delay */
		HAL_Delay(arg_int);
		break;
	case U8X8_MSG_GPIO_E:
		/* Insert codes for SS pin control */
		HAL_GPIO_WritePin(GPIOE, WR_Pin, arg_int);
		break;
	case U8X8_MSG_GPIO_CS:
		/* Insert codes for SS pin control */
		HAL_GPIO_WritePin(GPIOE, CE_Pin, arg_int);
		break;
	case U8X8_MSG_GPIO_DC:
		/* Insert codes for DC pin control */
		HAL_GPIO_WritePin(GPIOE, CD_Pin, arg_int);
		break;
	case U8X8_MSG_GPIO_RESET:
		/* Insert codes for RST pin control */
		HAL_GPIO_WritePin(GPIOE, GPIO_PIN_4, arg_int);
		break;

	case U8X8_MSG_GPIO_D0:				// D0 or SPI clock pin: Output level in arg_int
		HAL_GPIO_WritePin(GPIOE, D0_Pin, arg_int);
		break;
	case U8X8_MSG_GPIO_D1:				// D1 or SPI data pin: Output level in arg_int
		HAL_GPIO_WritePin(GPIOE, D1_Pin, arg_int);
		break;
	case U8X8_MSG_GPIO_D2:				// D2 pin: Output level in arg_int
		HAL_GPIO_WritePin(GPIOE, D2_Pin, arg_int);

		break;
	case U8X8_MSG_GPIO_D3:				// D3 pin: Output level in arg_int
		HAL_GPIO_WritePin(GPIOE, D3_Pin, arg_int);

		break;
	case U8X8_MSG_GPIO_D4:				// D4 pin: Output level in arg_int
		HAL_GPIO_WritePin(GPIOE, D4_Pin, arg_int);

		break;
	case U8X8_MSG_GPIO_D5:				// D5 pin: Output level in arg_int
		HAL_GPIO_WritePin(GPIOE, D5_Pin, arg_int);

		break;
	case U8X8_MSG_GPIO_D6:				// D6 pin: Output level in arg_int
		HAL_GPIO_WritePin(GPIOE, D6_Pin, arg_int);

		break;
	case U8X8_MSG_GPIO_D7:				// D7 pin: Output level in arg_int
		HAL_GPIO_WritePin(GPIOE, D7_Pin, arg_int);
		break;

	default:
		u8x8_SetGPIOResult(u8x8, 1);			// default return value
		break;
	}

	return 1;
}``