HAL_UART_Receive_IT (&huart3, Rx_data, 4) ?

[antonius]

Dear Members,

I have this code :

HAL_UART_Receive_IT (&huart3, Rx_data, 4);

I tested from RealTerm, it worked but I need to click "send" 4 times,

How can I make it only one click for the whole string ?

In STM32 side :

char Rx_data[10];
 char buf2 [] = "1234";
 char buf3 [] = "5678";
.
.
.
i = strcmp (Rx_data,buf2);
		 if (i==0)
		 {
      printf("char match RELAY 1 OFF \n");
			HAL_GPIO_WritePin(GPIOD, GPIO_PIN_14,GPIO_PIN_SET);  // RELAY OFF
				//HAL_UART_Receive_IT(&huart3, Rx_data, 4); 
			
     }
		 i = strcmp (Rx_data,buf3);
		 if (i==0)
		 {
      printf("char match RELAY 1 ON\n");
			HAL_GPIO_WritePin(GPIOD, GPIO_PIN_14,GPIO_PIN_RESET);  // RELAY ON
			 	//HAL_UART_Receive_IT(&huart3, Rx_data, 4);
     }			 

Any ideas how ?

Cheers

[antonius]

The code I use in PC , I developed with delphi,

procedure TForm1.Button3Click(Sender: TObject);
var
  BytesWritten: DWORD;
 
begin
     {SEND COM}
     //Relay ON
    s :='5678';
    s := s + #13;
    WriteFile(ComFile, s[1], Length(s), BytesWritten, nil);
 
end;

Which part is not correct ? STM32 side or PC side ?

Thanks

[Tesla DeLorean]

Not going to be able to diagnose from random disconnected fragments of code.

When the buffer gets filled you will get a callback, HAL_UART_Receive_IT(&huart3, Rx_data, 4) returns immediately. it will not zero terminate the buffer as a string, you will need to insure that if using string functions.

Perhaps create a polled loop we you see all 4 or 5 characters, one at a time.

[antonius]

Hi Clive, thanks for the reply,

...............

create a polled loop we you see all 4 or 5 characters, one at a time

..........

will it be nearly the same on how to decode GPS message, we spoke before ?

[Tesla DeLorean]

Well you could use that as a template.

You might want to check out the UART interrupt examples for your platform.

Generally the issue with requesting 4 characters is that if you get over or under you might not stay synchronized

[antonius]

Thanks for the reply,

I did this experiment :

if (Verbose)
  {
    puts("Decode UART3");
    printf("%s\n",s);
  }
	printf("Check the line synchronization\n");
	
		f=0;
	while(1)
	{
		 field[f++] = s;
		   while((*s != 0x0D) && (*s != 0x0A))
				 s++; //Line 173 sim900.h
		  if ((*s == 0x0D) || (*s == 0x0A) || (f == (FIELD_MAX - 1)))
      {
				*s = 0;
				field[f] = NULL;
				break;
      }
 
    *s++ = 0;	 // Line 183 sim900.h
	}	
	
	if (Verbose)
  {
    printf("Fields %02d\n",f);
 
    for(i=0; i<f; i++)
      printf("#%02d : %s\n",i,field[i]);
  }
	if ((strcmp(&field[0][3],"1234") == 0) && (f > 5)) // is it 1234 ?
    {
			//Turn on port
			printf("1234 Received \n");
		}	
 

I gave input 1234+CR from RealTerm,

and got output :

                                                    Decode UART3
               
                                                                 (
            
                                                                    Check the li
ne synchronization
                                                             
                   Fields 01
                                                   
                             #00 : (
                                          
                                      Decode UART3
                             
                                                   (
                          
                                                      Check the line synchroniza
tion
                                                                           
     Fields 01
                                                                 
               #00 : (
                                                        
                        Decode UART3
                                           
                                     (
                                        
                                        Check the line synchronization
         
                                                                       Fields 01
 
                                                                               
 #00 : (
                                                                      
                 

almost get it, which part should I fix ? thanks