replace method in python

s="ababa"
print(s)
s1=s.replace('a','b')
print(s1)

output:
ababa
bbbbb

example 2:


s="ababa"
print(s)
print("address of ::",id(s))
s1=s.replace('a','b')
print(s1)
print("address of ::",id(s1))

output:

ababa
address of :: 1358579616712
bbbbb
address of :: 1358567155280


example 3:

string data type is immutable but create the new object



s="ababa"
print(s)
print("address of ::",id(s))
s=s.replace('a','b')
print(s)
print("address of ::",id(s))

output:
ababa
address of :: 1358579616712
bbbbb
address of :: 1358579722816

"sizeof" function in c language

#include <stdio.h>
#include <stdlib.h>

int main()
{
   int a =0;
   char c="b";
   float d=1.10;
   long e=12345678;
   double f=1234567812345;
   long double g=123456789;
   printf("int==%d\nchar==%d\nfloat====%d",sizeof(a),sizeof(c),sizeof(d));
   printf("\nlong==%d",sizeof(e));
   printf("\ndouble==%d",sizeof(f));
   printf("\nlong double==%d",sizeof(g));
    return 0;
}

output:

int==4
char==1
float====4
long==4
double==8

long double==12

note :i am using code block ide ...so my values are like this ....if your using any other compiler then values will be changed as per the compiler

MM32 INSTALLATION ON KEIL

IC PACKAGES

• BQFPH - Bumpered Quad Flat Pack with Heat spreader:   This form of quad flat package utilises the pin protectors at the corners, it also has heat spreaders to enable larger levels of power to be dissipated.
• CQFP - Ceramic Quad Flat Pack:   This is a high quality version of the quad flat pack using ceramic for the package.
• FQFP - Fine pitched Quad Flat Pack:   A quad flat pack with, as the name indicates, a fine pitch for the pins.
• HQFP - Heat sinked Quad Flat Pack:   With many integrated circuits, especially those with high pins counts which have a high level of circuitry may dissipate high levels of heat. This heat may need to be removed. To achieve this a number of the pins, often in the centre of opposing sides are replaced with a thicker pin which is soldered to a large pad on the PCB with a large area of copper connected to it. This will remove a significant amount of heat.
• LQFP - Low profile Quad Flat Pack:   The Low Profile Quad Flat Pack is based upon the metric QFP, MQFP, but it is are thinner with a body thickness or height of 1.4mm. This helps solve problems where component height may be a problem. It has a standard lead-frame footprint - 2.0mm lead footprint. Lead counts for the LQFP range from 32 to 256. Body sizes range from 5 x 5mm to 28 x 28mm. Lead pitches available for LQFP package are 0.3, 0.4, 0.5, & 0.65mm.
• MQFP - Metric Quad Flat Pack:   A quad flat package where the measurements and in particular the pin spacing is defined in metric dimensions. Standard QFPs normally use Imperial measurements and have pin spacing etc defined in terms of convenient Imperial dimensions.
• PQFP - Plastic Quad Flat Pack:   A quad flat pack where the package material is plastic. Some QFPs can use ceramic.
• TQFP - Thin Quad Flat Pack:   The Thin Quad Flat Pack, TQFP is a form of low profile quad flat pack. Having a body thickness of 1.0mm and have a standard lead-frame footprint with 2.0mm lead footprint. The TQFP package material used is plastic.

WHILE loop in python

EXAMPLE 1:
while 1:
    print("Hello")

output:
Hello
Hello
Hello
Hello
Hello
Hello
Hello
Hello
Hello
Hello
Hello
......

EXAMPLE 2:

x=0
while 1:
    print(x)

    x+=1

output:
1
2
3
4
5
.....

FOR loop in python

in loops concept For loop plays major role

range is inbuilt function which is having 3 integers values
range(start,stop,step)
start---from where to start the iteration
stop---upto which value(max value) to execute
step---how much increment is looking for each iteration


example 1:

for x in range(1,10):
    print(x)

out put:
1
2
3
4
5
6
7
8
9



example 2:

for x in range(1,10):

    print("*")

output:
*
*
*
*
*
*
*
*
*

nested for loop

for x in range(1,5):
    for y in range (1,5):

          print("*")

output:
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*

example 4:
for x in range(2, 30, 3):
  print(x)

output:
2
5
8
11
14
17
20
23
26
29

example 5:
adj = ["red", "big", "tasty"]
fruits = ["apple", "banana", "cherry"]

for x in adj:
  for y in fruits:

    print(x, y)

output:
red apple
red banana
red cherry
big apple
big banana
big cherry
tasty apple
tasty banana
tasty cherry

example 6:
sentence = ["the", "quick", "brown", "fox", "jumped", "over", "the", "lazy", "dog"]

for i in sentence:
    print(i)
    i=+1

output:
the
quick
brown
fox
jumped
over
the
lazy
dog

stm32f103c8t6 with uart communication

main lines to add:
uint8_t bufftx[10]="Hello\n\r";
while (1)
  {
    /* USER CODE END WHILE */
HAL_UART_Transmit(&huart2, bufftx, 10,100);
HAL_Delay(1000);
    /* USER CODE BEGIN 3 */

  }



/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2019 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"

/* 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 */

/* USER CODE END PD */

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

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
UART_HandleTypeDef huart1;
UART_HandleTypeDef huart2;

/* USER CODE BEGIN PV */
uint8_t bufftx[10]="Hello\n\r";

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART1_UART_Init(void);
static void MX_USART2_UART_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();
  MX_USART1_UART_Init();
  MX_USART2_UART_Init();
  /* USER CODE BEGIN 2 */

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
HAL_UART_Transmit(&huart2, bufftx, 10,100);
HAL_Delay(1000);
    /* 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};

  /** Initializes the CPU, AHB and APB busses clocks
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI_DIV2;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL16;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
  /** Initializes the CPU, AHB and APB busses 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_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief USART1 Initialization Function
  * @param None
  * @retval None
  */
static void MX_USART1_UART_Init(void)
{

  /* USER CODE BEGIN USART1_Init 0 */

  /* USER CODE END USART1_Init 0 */

  /* USER CODE BEGIN USART1_Init 1 */

  /* USER CODE END USART1_Init 1 */
  huart1.Instance = USART1;
  huart1.Init.BaudRate = 115200;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART1_Init 2 */

  /* USER CODE END USART1_Init 2 */

}

/**
  * @brief USART2 Initialization Function
  * @param None
  * @retval None
  */
static void MX_USART2_UART_Init(void)
{

  /* USER CODE BEGIN USART2_Init 0 */

  /* USER CODE END USART2_Init 0 */

  /* USER CODE BEGIN USART2_Init 1 */

  /* USER CODE END USART2_Init 1 */
  huart2.Instance = USART2;
  huart2.Init.BaudRate = 9600;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART2_Init 2 */

  /* USER CODE END USART2_Init 2 */

}

/**
  * @brief GPIO Initialization Function
  * @param None
  * @retval None
  */
static void MX_GPIO_Init(void)
{

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

}

/* 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 */

  /* 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****/

output :

stm32 with lora(rfm95) stmcube connections

difference between 8-bit micro controller and 16-bit micro controller

Microcontrollers are like small computers that can carry out small programs and are often used for automation and robotics. The most popular to those who are just starting out are 8 bit and 16 bit microcontrollers. The main difference between 8 bit and 16 bit microcontrollers is the width of the data pipe. As you may have already deduced, an 8 bit microcontroller has an 8 bit data pipe while a 16 bit microcontroller has a 16 bit data pipe.

This fundamental difference between 8 bit and 16 bit microcontrollers is felt during mathematical operations. A 16 bit number gives you a lot more precision than 8 bit numbers. Although relatively rare, using an 8 bit microcontroller may not suffice the required accuracy of the application. 16 bit microcontrollers are also more efficient in processing math operations on numbers that are longer than 8 bits. A 16 bit microcontroller can automatically operate on two 16 bit numbers, like the common definition of an integer. But when you are using an 8 bit microcontroller, the process is not as straightforward. The functions implemented to operate on such numbers will take additional cycles. Depending on how processing intensive your application is and on how many calculations you do, this may affect the performance of the circuit.

Another key difference between 8 bit and 16 bit microcontrollers is in their timers. 8 bit microcontrollers can only use 8 bits, resulting in a final range of 0x00 – 0xFF (0-255) every cycle. In contrast, 16 bit microcontrollers, with its 16 bit data width, has a range of 0x0000 – 0xFFFF (0-65535) for every cycle. A longer timer maximum value can surely come in handy in certain applications and circuits.

Initially, the price of 16 bit microcontrollers was way above that of 8 bit microcontrollers. But as time progressed and designs improved, the price of 8 bit and 16 bit microcontrollers has reduced quite a lot. 8 bit microcontrollers can be purchased dirt cheap. While 16 bit microcontroller cost more, prices tend to vary a lot depending on the features that are included in the microcontroller.

Summary:

16 bit microcontrollers have twice as long data pipe than the 8 bit microcontroller

16 bit microcontrollers are more accurate at math than

16 bit microcontrollers are more efficient than 8 bit microcontrollers in math operation greater than 8 bits

16 bit microcontrollers have longer timers than 8 bit microcontrollers

16 bit microcontrollers are slightly more expensive than 8 bit microcontrollers

STM32F103C8T6 WITH KEIL LED BLINK

STM32F103C8T6 WITH KEIL LED BLINK :

How to code stm32xx using keil using STM cube Mx
main code changes
HAL_GPIO_TogglePin(GPIOC,GPIO_PIN_14);
 HAL_Delay(1000);



/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2019 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"

/* 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 */

/* 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 */

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
HAL_GPIO_TogglePin(GPIOC,GPIO_PIN_14);
HAL_Delay(1000);
    /* 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};

  /** Initializes the CPU, AHB and APB busses clocks
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
  /** Initializes the CPU, AHB and APB busses 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_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

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

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

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOC, GPIO_PIN_14, GPIO_PIN_RESET);

  /*Configure GPIO pin : PC14 */
  GPIO_InitStruct.Pin = GPIO_PIN_14;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

}

/* 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 */

  /* 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****/

Two led blink code:

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2019 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"

/* 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 */

/* 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 */

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
HAL_GPIO_TogglePin(GPIOC,GPIO_PIN_13);
HAL_Delay(1000);
HAL_GPIO_TogglePin(GPIOC,GPIO_PIN_14);
HAL_Delay(1000);
    /* 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};

  /** Initializes the CPU, AHB and APB busses clocks
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
  /** Initializes the CPU, AHB and APB busses 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_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

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

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

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

  /*Configure GPIO pins : PC13 PC14 */
  GPIO_InitStruct.Pin = GPIO_PIN_13|GPIO_PIN_14;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

}

/* 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 */

  /* 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****/

Rfm95 with arduino uno working with serial communication

Rfm95 with arduino uno working with serial communication:

connection with arduino uno

ARDUINO UNO	RFM 95
Gnd	Gnd
3.3v	3.3v
D5	reset
D2	DIO 0
D3	DIO1
D13(SCK)	SCK
D12(MISO)	MISO
D11(MOSI)	MOSI
D10(SS)	NSS

NOTE:

LEVEL SHIFTER FOR BETTER OUTPUT

sender side code:

#include <SPI.h>

#include <RH_RF95.h>

RH_RF95 rf95;

int led = 9;

void setup() 

{

  pinMode(led, OUTPUT);     

  Serial.begin(9600);

  while (!Serial) ; // Wait for serial port to be available

  if (!rf95.init())

    Serial.println("init failed");  

}

void loop()

{

  if (rf95.available())

  {// Should be a message for us now   

    uint8_t buf[RH_RF95_MAX_MESSAGE_LEN];

    uint8_t len = sizeof(buf);

    if (rf95.recv(buf, &len))

    {

      digitalWrite(led, HIGH);

     // RH_RF95::printBuffer("request: ", buf, len);

      Serial.print("got request: ");

      Serial.println((char*)buf);

      sender_fn();

    }

    else

    {

      Serial.println("recv failed");

    }

  }

  delay(100);

}

void sender_fn()

{

  /***************************************/

      // Send a reply

  /***************************************/

    char data[32]="";

   int availableBytes = Serial.available();

    if(availableBytes>0)

   {

       for(int i=0; i<availableBytes; i++)

       {     

           data[i]=Serial.read();

       } 

          rf95.send(data, sizeof(data));

          rf95.waitPacketSent();

           Serial.print("Sent::");

           Serial.print(data);

           digitalWrite(led, LOW);

        

   }

  }

Receiver side code:

// rf95_client.pde

#include <SPI.h>
#include <RH_RF95.h>

int led = 9;
RH_RF95 rf95;
void setup()
{
  pinMode(led, OUTPUT); 
  Serial.begin(9600);
  while (!Serial) ; // Wait for serial port to be available
  if (!rf95.init())
    Serial.println("init failed");
}

void loop()
{
  rfm95_uart();
}

void rfm95_uart()
{
   uint8_t buf[RH_RF95_MAX_MESSAGE_LEN];
     uint8_t len = sizeof(buf);
      if (rf95.waitAvailableTimeout(3000))
      {
         //Serial.print(rf95.recv(buf, &len));
           if (rf95.recv(buf, &len)>0)
           {
             Serial.print("got reply: ");
            Serial.println((char*)buf); 
          }
 
          else
          {
             Serial.println("recv failed");
          }
        }
        else
        {
          rfm95_uart_sndr();
            //Serial.println(".");
            //Serial.println("No reply, is rf95_server running?");
       }
  delay(10);
}

void rfm95_uart_sndr()
{
   //Serial.println("Sending to rf95_server::");
   char data[32]="";
   int availableBytes = Serial.available();
    //Serial.print(availableBytes);
   if(availableBytes>0)
   {
       for(int i=0; i<availableBytes; i++)
       {   
           data[i]=Serial.read();
       }
          rf95.send(data, sizeof(data));
          rf95.waitPacketSent();
           Serial.print("Sent::");
           Serial.print(data);
           digitalWrite(led, LOW);
   }

}

output :

for the code download the below link:

https://drive.google.com/file/d/1Hx0noPMxfg8zQdcvZqobS8y8dE7NbxSX/view?usp=sharing