µVISION DEBUGGER: HOW TO CONNECT TWO PORT PINS

Information in this article applies to:

• µVision Version 2 and Later

QUESTION

I need to simulate a connection between two port pins. Is this possible to do in the µVision simulator?

ANSWER

Yes. You must create a signal function that copies the output port pin to the input port pin. In general, the steps to do this are:

1. Use the wwatch function to wait for the Output PORTx VTReg to get written.
2. Read the pin value from the Output PORTx VTReg.
3. Write the pin value to the Input PORTx VTReg.

The following example connects the Output Pin (PORT1.7) to the Input Pin (PORT2.1). The application must configure P1.7 as an output and P2.1 as an input:

/* define port_loopback function */
signal void port_loopback (void) {
  printf("loopback signal function is started\n");
  while (1) {
    wwatch (PORT1);         /* wait for PORT1 (VTR) access      */
    if (PORT1 & 0x80) {     /* set PORT2.1 depending on PORT1.7 */
      PORT2 |= 0x02;
    } else {
      PORT2 &= ~0x02;
    }
  }
}

/* start port_loopback function */
port_loopback()

SEE ALSO

• µVision DEBUGGER: USING THE PORTX VTREGS
• µVision DEBUGGER: USING THE WWATCH BUILT-IN FUNCTION
• µVision DEBUGGER: CREATING INPUT SIGNAL PATTERNS
• µVision DEBUGGER: DIFFERENCE BETWEEN SFR AND VTREG

Last Reviewed: Wednesday, October 12, 2005