add code

+/* USER CODE BEGIN Header */
+/**
+  ******************************************************************************
+  * @file           : main.c
+  * @brief          : Main program body
+  ******************************************************************************
+  * @attention
+  *
+  * <h2><center>&copy; Copyright (c) 2020 STMicroelectronics.
+  * All rights reserved.</center></h2>
+  *
+  * This software component is licensed by ST under BSD 3-Clause license,
+  * the "License"; You may not use this file except in compliance with the
+  * License. You may obtain a copy of the License at:
+  *                        opensource.org/licenses/BSD-3-Clause
+  *
+  ******************************************************************************
+  */
+/* USER CODE END Header */
+/* Includes ------------------------------------------------------------------*/
+#include "main.h"
+#include "tim.h"
+#include "usart.h"
+#include "gpio.h"
+
+/* Private includes ----------------------------------------------------------*/
+/* USER CODE BEGIN Includes */
+#include <math.h>
+#include <stdbool.h>
+/* USER CODE END Includes */
+
+/* Private typedef -----------------------------------------------------------*/
+/* USER CODE BEGIN PTD */
+
+/* USER CODE END PTD */
+
+/* Private define ------------------------------------------------------------*/
+/* USER CODE BEGIN PD */
+/* USER CODE END PD */
+
+/* Private macro -------------------------------------------------------------*/
+/* USER CODE BEGIN PM */
+
+/* USER CODE END PM */
+
+/* Private variables ---------------------------------------------------------*/
+
+/* USER CODE BEGIN PV */
+uint8_t rx2_data = 0;
+
+uint32_t desired_speed = 3000;
+uint32_t MOTER_PWM[4] = {0};
+uint32_t Kp = 1;
+uint32_t encoder_cnt[4] = {0};
+uint32_t encoder_speed[4] = {0};
+int32_t error_speed[4] = {0};
+int32_t PID_speed[4] = {0};
+uint32_t old_PID_speed[4] = {3000, 3000, 3000, 3000};
+
+/***********lidar************/
+//response data
+bool scan_start = false;
+uint8_t rx3_start[7] = {0};
+uint8_t rx3_data[5] = {0};
+uint8_t Q = 0;
+bool S = false;
+uint16_t angle;
+uint16_t d;
+uint16_t distance[360] = {0};
+int16_t avg_DIFF = 0;
+
+//protocal
+uint8_t scan_command[2] = {0xA5,0x20};
+uint8_t stop_command[2] = {0xA5,0x25};
+uint8_t soft_reboot[2] = {0xA5,0x40};
+uint8_t scan_express[2] = {0xA5,0x82};
+uint8_t scan_force[2] = {0xA5,0x21};
+uint8_t device_info[2] = {0xA5,0x50};
+uint8_t health_status[2] = {0xA5,0x52};
+uint8_t sample_rate[2] = {0xA5,0x59};
+uint8_t scan_response[7] = {0xa5, 0x5a, 0x5, 0x0, 0x0, 0x40, 0x81};
+/* USER CODE END PV */
+
+/* Private function prototypes -----------------------------------------------*/
+void SystemClock_Config(void);
+static void MX_NVIC_Init(void);
+/* USER CODE BEGIN PFP */
+
+/* USER CODE END PFP */
+
+/* Private user code ---------------------------------------------------------*/
+/* USER CODE BEGIN 0 */
+bool array_element_of_index_equal(uint8_t a[], uint8_t b[], uint8_t size) {
+   uint8_t i;
+   for(i=0; i<size; i++){
+      if( a[i] != b[i] )
+         return false;
+   }
+   return true;
+}
+int16_t array_avg_compare(uint16_t distance[]){
+
+   uint32_t sum_R = 0;
+   uint32_t sum_L = 0;
+   uint8_t len_L = 0;
+   uint8_t len_R = 0;
+   uint16_t avg_R = 0;
+   uint16_t avg_L = 0;
+   int16_t avg_diff = 0;
+
+   for(int i=0; i<90; i++){
+      sum_R += distance[i];
+      if(distance[i]!=0){
+         len_R++;
+      }
+   }
+   avg_R = sum_R/len_R;
+
+   for(int i=270; i<360; i++){
+      sum_L += distance[i];
+      if(distance[i]!=0){
+         len_L++;
+      }
+   }
+   avg_L = sum_L/len_L;
+
+   avg_diff = avg_R - avg_L;
+
+   return avg_diff;
+}
+void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)	//Timer interrupt every 20ms
+{
+	if(htim->Instance == TIM6){
+
+		//HAL_GPIO_WritePin(GPIOC,GPIO_PIN_13,GPIO_PIN_SET);
+		encoder_cnt[0] = TIM2->CNT;
+		TIM2->CNT=0;
+
+		encoder_cnt[1] = TIM3->CNT;
+		TIM3->CNT=0;
+
+		encoder_cnt[2] = TIM4->CNT;
+		TIM4->CNT=0;
+
+		encoder_cnt[3] = TIM5->CNT;
+		TIM5->CNT=0;
+
+		encoder_speed[0] = 164.18 * exp(0.0112*encoder_cnt[0]);
+		encoder_speed[1] = 164.18 * exp(0.0112*encoder_cnt[1]);
+		encoder_speed[2] = 164.18 * exp(0.0112*encoder_cnt[2]);
+		encoder_speed[3] = 164.18 * exp(0.0112*encoder_cnt[3]);
+
+		error_speed[0] = desired_speed - encoder_speed[0];
+		error_speed[1] = desired_speed - encoder_speed[1];
+		error_speed[2] = desired_speed - encoder_speed[2];
+		error_speed[3] = desired_speed - encoder_speed[3];
+
+		PID_speed[0] = old_PID_speed[0] + Kp*error_speed[0];
+		PID_speed[1] = old_PID_speed[1] + Kp*error_speed[1];
+		PID_speed[2] = old_PID_speed[2] + Kp*error_speed[2];
+		PID_speed[3] = old_PID_speed[3] + Kp*error_speed[3];
+
+		old_PID_speed[0] = PID_speed[0];
+		old_PID_speed[1] = PID_speed[1];
+		old_PID_speed[2] = PID_speed[2];
+		old_PID_speed[3] = PID_speed[3];
+	}
+}
+
+/* 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();
+  MX_TIM1_Init();
+  MX_TIM2_Init();
+  MX_TIM3_Init();
+  MX_TIM4_Init();
+  MX_TIM6_Init();
+  MX_USART2_UART_Init();
+  MX_USART3_UART_Init();
+  MX_TIM5_Init();
+
+  /* Initialize interrupts */
+  MX_NVIC_Init();
+  /* USER CODE BEGIN 2 */
+
+  HAL_Delay(3000);
+
+  //Initialize for motor PWM
+  HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);
+  HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_2);
+  HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_3);
+  HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_4);
+
+  //Initialize for motor direction
+  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, SET);
+  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_13, RESET);
+
+  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_14, SET);
+  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_15, RESET);
+
+  HAL_GPIO_WritePin(GPIOD, GPIO_PIN_8, SET);
+  HAL_GPIO_WritePin(GPIOD, GPIO_PIN_9, RESET);
+
+  HAL_GPIO_WritePin(GPIOD, GPIO_PIN_10, SET);
+  HAL_GPIO_WritePin(GPIOD, GPIO_PIN_11, RESET);
+
+  //Initialize for encoder count value
+  TIM2->CNT = 0;
+  TIM3->CNT = 0;
+  TIM4->CNT = 0;
+  TIM5->CNT = 0;
+
+  //Initialize for Encoder
+  HAL_TIM_Encoder_Start(&htim2, TIM_CHANNEL_ALL);
+  HAL_TIM_Encoder_Start(&htim3, TIM_CHANNEL_ALL);
+  HAL_TIM_Encoder_Start(&htim4, TIM_CHANNEL_ALL);
+  HAL_TIM_Encoder_Start(&htim5, TIM_CHANNEL_ALL);
+
+  //Initialize for timer interrupt initialization for Encoder (50ms)
+  HAL_TIM_Base_Start_IT(&htim6);
+
+  //LIDAR_scan_start
+  //HAL_UART_Transmit(&huart3, &scan_command, 2, 100);
+
+  //robotArm to Cart
+  HAL_UART_Receive_IT(&huart2,&rx2_data,1);
+
+
+  /* USER CODE END 2 */
+
+  /* Infinite loop */
+  /* USER CODE BEGIN WHILE */
+
+  while(1){
+
+	if(rx2_data == 1){
+		 HAL_GPIO_WritePin(GPIOC,GPIO_PIN_13, GPIO_PIN_RESET);
+		 HAL_GPIO_WritePin(GPIOE, GPIO_PIN_4, RESET);
+		 HAL_GPIO_WritePin(GPIOE, GPIO_PIN_5, SET);
+		 //go left
+		 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, SET);
+		 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_13, RESET);
+
+		 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_14, RESET);
+		 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_15, SET);
+
+		 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_8, RESET);
+		 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_9, SET);
+
+		 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_10, SET);
+		 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_11, RESET);
+		 /*
+		 TIM1->CCR1 = 6000;
+		 TIM1->CCR2 = 4500;
+		 TIM1->CCR3 = 8000;
+		 TIM1->CCR4 = 9999;
+		 */
+		 TIM1->CCR1 = 8000;
+		 TIM1->CCR2 = 9999;
+		 TIM1->CCR3 = 6000;
+		 TIM1->CCR4 = 4500;
+
+		 HAL_Delay(100);
+
+		 rx2_data = 5;
+		 //HAL_Delay(2000);
+
+
+
+
+	}else if(rx2_data == 2){
+		 HAL_GPIO_WritePin(GPIOC,GPIO_PIN_13, GPIO_PIN_SET);
+		 HAL_GPIO_WritePin(GPIOE, GPIO_PIN_4, SET);
+		 HAL_GPIO_WritePin(GPIOE, GPIO_PIN_5, RESET);
+		 //go right
+		 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, RESET);
+		 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_13, SET);
+
+		 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_14, SET);
+		 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_15, RESET);
+
+		 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_8, SET);
+		 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_9, RESET);
+
+		 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_10, RESET);
+		 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_11, SET);
+
+		 TIM1->CCR1 = 8000;
+		 TIM1->CCR2 = 9999;
+		 TIM1->CCR3 = 6000;
+		 TIM1->CCR4 = 4500;
+
+		 HAL_Delay(100);
+
+		 rx2_data = 5;
+		 //HAL_Delay(2000);
+
+	}else if(rx2_data == 5){
+		//stop
+
+		TIM1->CCR1 = 0;
+		TIM1->CCR2 = 0;
+		TIM1->CCR3 = 0;
+		TIM1->CCR4 = 0;
+
+	}else if(rx2_data == 3){
+		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, SET);
+		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_13, RESET);
+
+		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_14, SET);
+		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_15, RESET);
+
+		HAL_GPIO_WritePin(GPIOD, GPIO_PIN_8, SET);
+		HAL_GPIO_WritePin(GPIOD, GPIO_PIN_9, RESET);
+
+		HAL_GPIO_WritePin(GPIOD, GPIO_PIN_10, SET);
+		HAL_GPIO_WritePin(GPIOD, GPIO_PIN_11, RESET);
+		TIM1->CCR1 = 3000;
+		TIM1->CCR2 = 3000;
+		TIM1->CCR3 = 3000;
+		TIM1->CCR4 = 3000;
+
+
+
+	}else if(rx2_data == 6){
+
+		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, SET);
+		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_13, RESET);
+
+		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_14, SET);
+		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_15, RESET);
+
+		HAL_GPIO_WritePin(GPIOD, GPIO_PIN_8, SET);
+		HAL_GPIO_WritePin(GPIOD, GPIO_PIN_9, RESET);
+
+		HAL_GPIO_WritePin(GPIOD, GPIO_PIN_10, SET);
+		HAL_GPIO_WritePin(GPIOD, GPIO_PIN_11, RESET);
+
+		TIM1->CCR1 = 4000;
+		TIM1->CCR2 = 4000;
+		TIM1->CCR3 = 4000;
+		TIM1->CCR4 = 4000;
+
+		HAL_Delay(2000);
+
+		rx2_data = 5;
+
+	}
+
+/*
+	}else if(rx2_data == 11){
+
+			 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, RESET);
+			 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_13, SET);
+
+			 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_14, SET);
+			 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_15, RESET);
+
+			 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_8, SET);
+			 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_9, RESET);
+
+			 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_10, RESET);
+			 HAL_GPIO_WritePin(GPIOD, GPIO_PIN_11, SET);
+
+			 TIM1->CCR1 = 3000;
+			 TIM1->CCR2 = 9999;
+			 TIM1->CCR3 = 8000;
+			 TIM1->CCR4 = 3000;
+
+			 HAL_Delay(100);
+
+			 rx2_data = 5;
+			 //HAL_Delay(2000);
+
+		}*/
+	// rx2_data = 0;
+  }
+
+
+    /* 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_HSE;
+  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
+  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
+  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
+  RCC_OscInitStruct.PLL.PLLM = 4;
+  RCC_OscInitStruct.PLL.PLLN = 168;
+  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
+  RCC_OscInitStruct.PLL.PLLQ = 7;
+  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_PLLCLK;
+  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
+  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
+  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
+
+  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
+  {
+    Error_Handler();
+  }
+}
+
+/**
+  * @brief NVIC Configuration.
+  * @retval None
+  */
+static void MX_NVIC_Init(void)
+{
+  /* USART2_IRQn interrupt configuration */
+  HAL_NVIC_SetPriority(USART2_IRQn, 0, 0);
+  HAL_NVIC_EnableIRQ(USART2_IRQn);
+  /* TIM6_DAC_IRQn interrupt configuration */
+  HAL_NVIC_SetPriority(TIM6_DAC_IRQn, 0, 0);
+  HAL_NVIC_EnableIRQ(TIM6_DAC_IRQn);
+}
+
+/* USER CODE BEGIN 4 */
+void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
+{
+  if(huart->Instance==USART2){
+     HAL_UART_Receive_IT(&huart2,&rx2_data,1);
+  }
+}
+/* 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 */
+
+  /* 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,
+     tex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
+  /* USER CODE END 6 */
+}
+#endif /* USE_FULL_ASSERT */
+
+/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/