Impulse Patterns

The following Signal Function generates a signal impulse pattern as it is typical in many embedded systems. In this case it is the input of a DTMF receiver as they are common in telecom applications.

//
// Generate Input Signal Pattern from a DTMF Receiver
//
signal void SendDtmf (unsigned char digit)  {
  if (digit == 0)  digit = 10;
  PORT2 = (PORT2 & 0x07) | (digit << 4);
  swatch (0.06);
  PORT2 |= 0x8;
}

signal void Send (void)  {
  SendDtmf (12);    // send digit 12 = '*'
  swatch (0.12);
  SendDtmf (7);     // send digit 7
  swatch (0.12);
  SendDtmf (2);     // send digit 2
  swatch (0.12);
  SendDtmf (11);    // send digit 11 = '#'
}

The above Signal Function generates the following input pattern on Port 2.