After CANopen starts PDO timing transmission, the heartbeat frame time is wrong, PDO is delayed, and CANopen time axis is disordered

CANopen In the case of , A simple way to use a lot is to use a 1ms Timer interrupt , Then rewrite... With global variables sertimer and getElapsedTime function , Then add... To the interrupt service function timerForCan

//Set the next alarm //
void setTimer(TIMEVAL value)
{
    
        NextTime=(TimeCNT+value)%TIMER_MAX_COUNT;
}

// Get the elapsed time since the last occured alarm //
TIMEVAL getElapsedTime(void)
{
    
        int ret=0;
        ret = TimeCNT> last_time_set ? TimeCNT - last_time_set : TimeCNT + TIMER_MAX_COUNT - last_time_set;
        last_time_set = TimeCNT;
        return ret;
}

But there is a fatal problem with this approach , The time calculated in this way , When there are only heartbeat frames, there is no problem , Join in PDO Regularly send , Will be chaos , for example 1s Heartbeat frame 300msPDO timing , The phenomenon is 1s Heartbeat frame retention , stay 1s After heartbeat frame 300ms There will be one more heartbeat frame , and PDO Timed transmission does not appear ！！！！！！, In this case, it should be changed to last_time_set = TimeCNT; Put it in timerForCan Before ！！！！

```c
//Set the next alarm //
void setTimer(TIMEVAL value)
{
    
        NextTime=(TimeCNT+value)%TIMER_MAX_COUNT;
}

// Get the elapsed time since the last occured alarm //
TIMEVAL getElapsedTime(void)
{
    
        int ret=0;
        ret = TimeCNT> last_time_set ? TimeCNT - last_time_set : TimeCNT + TIMER_MAX_COUNT - last_time_set;
        //last_time_set = TimeCNT; The culprit 
        return ret;
}
 In addition, there will be a 1 Millisecond timer , Every time 1 Call the following function in milliseconds .
void timerForCan(void)
{
    
        TimeCNT++;
        if (TimeCNT>=TIMER_MAX_COUNT)
        {
    
                TimeCNT=0;
        }
        if (TimeCNT==NextTime)
        {
    
                TimeDispatch();
        }
}
//1ms Interrupt service function 
void TIM7_IRQHandler(void)
{
    
	if(TIM7->SR&0X0001)// interrupt 
	{
    
		
	}
	TIM7->SR&=~(1<<0);// Clears the interrupt flag bit  
	last_time_set = TimeCNT;
	timerForCan();
}