TVI Electronics, LLC

vivat wrote: ↑

Fri May 06, 2011 6:08 pm

Also, please make sure that you get these bingo bonus codes now in any place. The damage can be caused by sharp objects, excessive bending of the flex cable or excessive insertion of the flex cable's conductor into its receptacle during assembly. Some failure modes are not obvious to the naked eye.

The space character is the separator. I wouldn't use scanf.

Collect characters in a buffer until a space is received, then process the string. Replace the comma with a null character, remember where the comma is and you have two separate strings that can be converted to an integer using atoi(). Then restart collecting characters again.

Or something along the lines of this:

Code: Select all

// 
// Wait for a response from the touchscreen and store the x and y coordinates in the integers pointed to by x and y 
// 
void wait_for_response(int *x, int *y) 
{ 
 char x_buffer[8],y_buffer[8],*p; 
 char no_chars; // number of characters received, to prevent buffer overflows 
 char done; 

 // Start receiving response strings 
 p=x_buffer; 
 no_chars=0; 
 done=0; 
 do 
  { 
  ch=getchar(); // assuming blocking until something is received 

  if (ch==',')  // when a comma is received the x field is complete 
   { 
   *p=0; // terminate string 
   p=y_buffer; // switch pointer to y_buffer 
   no_chars=0; 
   } 
  else if (ch==' ') // when a space is received, the y_field is complete 
   { 
   *p=0; // terminate string 
   done=1; 
   } 
  else { // In all other cases store the character in the buffer 
       if (i<8) // Make sure we don't go past end of buffer 
        { 
        *p++=ch; 
        i+=1; 
        }        
       } 
  } while (!done); 

 *x=atoi(x_buffer); 
 *y=atoi(y_buffer); 
}

Of course this codesnippet just blocks the whole processor until the touchscreen sends a complete message. In practice you could place this code inside the UART ISR, except for the atoi() of course. Or make all variables static, and when getchar() indicates there's no character bail out of the function. Also, a bit of extra error checking should be added.