Реализация ModBus rtu на stm32f103

/* USER CODE BEGIN 0 */
static uint32_t lock_nesting_count = 0;
 
void __critical_enter(void)
{
    __disable_irq();//запрещает глобальные прерывания
    ++lock_nesting_count;
}
void __critical_exit(void)
{/* Разблокировать прерывания только тогда, когда мы выходим из самого внешнего вложенного вызова. */
    --lock_nesting_count;
    if (lock_nesting_count == 0)
    {
        __enable_irq();//разрешает глобальные прерывания
    }
}
/* 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_TIM4_Init();
  /* USER CODE BEGIN 2 */
  HAL_Delay(2000);
  xMBPortTimersInit( 20 );
  vMBPortTimersEnable();
  //vMBPortTimersDisable();
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
  }

#include <assert.h>
#include <inttypes.h>
#include "stm32f1xx_hal.h"
 
#define INLINE                      inline
#define PR_BEGIN_EXTERN_C           extern "C" {
#define PR_END_EXTERN_C             }
//=======================================================================
void __critical_enter(void);
void __critical_exit(void);
 
#define ENTER_CRITICAL_SECTION( )   ( __critical_enter( ) )//( __disable_irq() )
#define EXIT_CRITICAL_SECTION( )    ( __critical_exit( ) )//( __enable_irq() )
 
void prvvUARTTxReadyISR(void);
void prvvUARTRxISR(void);
...

#include "port.h"
#include "stm32f1xx_hal.h"
 
/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"
 
/* ----------------------- static functions ---------------------------------*/
static void prvvTIMERExpiredISR( void );
extern TIM_HandleTypeDef htim4;
uint16_t timeout = 0;
volatile uint16_t counter = 0;
/* ----------------------- Start implementation -----------------------------*/
BOOL
xMBPortTimersInit( USHORT usTim1Timerout50us )
{
    timeout = usTim1Timerout50us;
    return TRUE;
}
 
 
inline void
vMBPortTimersEnable(  )
{
    /* Enable the timer with the timeout passed to xMBPortTimersInit( ) */
    HAL_GPIO_TogglePin(GPIOA, GPIO_PIN_10);
    counter=0;
    HAL_TIM_Base_Start_IT(&htim4);
}
 
inline void
vMBPortTimersDisable(  )
{
    /* Disable any pending timers. */
    HAL_GPIO_TogglePin(GPIOA, GPIO_PIN_10);
    HAL_TIM_Base_Stop_IT(&htim4);
}
 
/* Create an ISR which is called whenever the timer has expired. This function
 * must then call pxMBPortCBTimerExpired( ) to notify the protocol stack that
 * the timer has expired.
 */
static void prvvTIMERExpiredISR( void )
{
    ( void )pxMBPortCBTimerExpired(  );
}
 
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  if((++counter)>=timeout)
  {
    prvvTIMERExpiredISR();
  }
}