/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2025 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */

#define DISPLAY_RS  ((uint16_t) (0x1U << 7))
#define DISPLAY_RW  ((uint16_t) (0x1U << 10))
#define DISPLAY_ENA ((uint16_t) (0x1U << 11))

#define UPDATE_STATUS GPIOD->ODR = ((GPIOE->ODR & DISPLAY_ENA) << 1) | ((GPIOE->ODR & DISPLAY_RS) << 6)
#define DISPLAY_CHAR_DELAY 1  // character
#define DISPLAY_COMM_DELAY 60 // command

#define DISPLAY_INSTRUCT_BYTE(byte)                         \
	do {                                                    \
		GPIOE->ODR = ((((uint16_t)(byte)) << 8) & 0xF000);  \
		UPDATE_STATUS;                                      \
		HAL_Delay(DISPLAY_COMM_DELAY);                           \
		GPIOE->BSRR = DISPLAY_ENA;                          \
		UPDATE_STATUS;                                      \
		HAL_Delay(DISPLAY_COMM_DELAY);                           \
		GPIOE->BSRR = (DISPLAY_ENA << 16);                  \
		UPDATE_STATUS;                                      \
		HAL_Delay(DISPLAY_COMM_DELAY);                           \
		                                                    \
		GPIOE->ODR = ((((uint16_t)(byte)) << 12) & 0xF000); \
		UPDATE_STATUS;                                      \
		HAL_Delay(DISPLAY_COMM_DELAY);                           \
		GPIOE->BSRR = DISPLAY_ENA;                          \
		UPDATE_STATUS;                                      \
		HAL_Delay(DISPLAY_COMM_DELAY);                           \
		GPIOE->BSRR = (DISPLAY_ENA << 16);                  \
		UPDATE_STATUS;                                      \
		HAL_Delay(DISPLAY_COMM_DELAY);                           \
	} while (0)

#define DISPLAY_DATA_BYTE(byte)                                            \
	do {                                                                   \
		GPIOE->ODR = (((((uint16_t)(byte)) << 8) & 0xF000) | DISPLAY_RS);  \
		UPDATE_STATUS;                                                     \
		HAL_Delay(DISPLAY_CHAR_DELAY);                                          \
		GPIOE->BSRR = DISPLAY_ENA;                                         \
		UPDATE_STATUS;                                                     \
		HAL_Delay(DISPLAY_CHAR_DELAY);                                          \
		GPIOE->BSRR = (DISPLAY_ENA << 16);                                 \
		UPDATE_STATUS;                                                     \
		HAL_Delay(DISPLAY_CHAR_DELAY);                                          \
		                                                                   \
		GPIOE->ODR = (((((uint16_t)(byte)) << 12) & 0xF000) | DISPLAY_RS); \
		UPDATE_STATUS;                                                     \
		HAL_Delay(DISPLAY_CHAR_DELAY);                                          \
		GPIOE->BSRR = DISPLAY_ENA;                                         \
		UPDATE_STATUS;                                                     \
		HAL_Delay(DISPLAY_CHAR_DELAY);                                          \
		GPIOE->BSRR = (DISPLAY_ENA << 16);                                 \
		UPDATE_STATUS;                                                     \
		HAL_Delay(DISPLAY_CHAR_DELAY);                                          \
	} while (0)

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{

  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  /* USER CODE BEGIN 2 */
  DISPLAY_INSTRUCT_BYTE(0x01);

  GPIOD->ODR = 0xF000;
  HAL_Delay(1000);

  //HAL_GPIO_WritePin(GPIOD, GPIO_PIN_15, GPIO_PIN_SET);

  uint8_t display_status = 0x0;
  int attempts_left;

  while (1) {
	  GPIOE->MODER &= 0x00FFFFFFU;
	  attempts_left = 10;

	  do {
		  if (GPIOE->MODER & 0xFF000000U) {
			  // port didn't switch mode
			  GPIOD->ODR = 0x4000U;
			  while (1) {}
		  } else {
			  GPIOD->ODR = 0x0U;
		  }

		  GPIOE->BSRR = DISPLAY_RW | (DISPLAY_RS << 16);
		  GPIOE->BSRR = DISPLAY_ENA;
		  HAL_Delay(20);
		  display_status = (GPIOE->IDR & 0xF000) >> 8;
		  GPIOE->BSRR = (DISPLAY_ENA << 16);
		  HAL_Delay(20);


		  GPIOE->BSRR = DISPLAY_ENA;
		  HAL_Delay(20);
		  display_status |= (GPIOE->IDR & 0xF000) >> 12;
		  GPIOE->BSRR = (DISPLAY_ENA << 16);
		  HAL_Delay(20);


		  GPIOD->ODR = ((display_status & 0xF0) << 8);

		  HAL_Delay(50);
	  } while (((display_status & 0x80) || ((display_status & 0x7F) != 0)) && attempts_left--);

	  if (!((display_status & 0x80) || ((display_status & 0x7F) != 0)))
		  break;

	  GPIOD->ODR = 0x0U;
	  GPIOE->ODR = 0x0U;
	  GPIOE->BSRR = DISPLAY_ENA;
	  HAL_Delay(20);
	  GPIOE->BSRR = (DISPLAY_ENA << 16);
	  HAL_Delay(20);

	  GPIOE->BSRR = DISPLAY_ENA;
	  HAL_Delay(20);
	  GPIOE->BSRR = (DISPLAY_ENA << 16);
	  HAL_Delay(20);

	  GPIOE->MODER |= 0x55000000U;

	  GPIOE->BSRR = DISPLAY_ENA;
	  HAL_Delay(20);
	  GPIOE->BSRR = (DISPLAY_ENA << 16);
	  HAL_Delay(20);

	  DISPLAY_INSTRUCT_BYTE(0x01);

	  HAL_Delay(500);
  }

  GPIOD->ODR = 0x0U;

  GPIOE->ODR = 0x0U;

  /*
  GPIOE->BSRR = DISPLAY_ENA;
  HAL_Delay(1);
  GPIOE->BSRR = (DISPLAY_ENA << 16);
  HAL_Delay(1);

  GPIOE->BSRR = DISPLAY_ENA;
  HAL_Delay(1);
  GPIOE->BSRR = (DISPLAY_ENA << 16);
  HAL_Delay(1);
  */

  GPIOE->MODER |= 0x55000000U;



  // init display
  /*
  GPIOE->BSRR = DISPLAY_ENA;
  HAL_Delay(1);
  GPIOE->BSRR = (DISPLAY_ENA << 16);
  HAL_Delay(1);
  */


  // reset (supposedly)
  DISPLAY_INSTRUCT_BYTE(0x01);

  // switch to 4-bit 2-line mode
  DISPLAY_INSTRUCT_BYTE(0x28);

  // write characters
  char a[] = "Well, hi there!";
  for (int i = 0; i < sizeof(a)-1; i++) {
	  DISPLAY_DATA_BYTE(a[i]);
  }

  // next line
  DISPLAY_INSTRUCT_BYTE(0xC0);

  // write more characters
  char b[] = "I'm doing it!";
  for (int i = 0; i < sizeof(b)-1; i++) {
	  DISPLAY_DATA_BYTE(b[i]);
  }

  GPIOE->ODR = 0x0U;
  UPDATE_STATUS;

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Configure the main internal regulator output voltage
  */
  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief GPIO Initialization Function
  * @param None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOE_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOE, GPIO_PIN_7|GPIO_PIN_10|GPIO_PIN_11|GPIO_PIN_12
                          |GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOD, GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15, GPIO_PIN_RESET);

  /*Configure GPIO pins : PE7 PE10 PE11 PE12
                           PE13 PE14 PE15 */
  GPIO_InitStruct.Pin = GPIO_PIN_7|GPIO_PIN_10|GPIO_PIN_11|GPIO_PIN_12
                          |GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);

  /*Configure GPIO pins : PD12 PD13 PD14 PD15 */
  GPIO_InitStruct.Pin = GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */