19. Is the instruction "CPL Pi" a valid instruction? 20. Write a program to toggle P1.2 and P1.5 continuously without disturbing the rest of the bits. 21. Write a program to toggle P1.3, P1.7, and P2.5 continuously without disturb- ing the rest of the bits. 22. Write a program to monitor bit P1.3. When it is high, send 55H to P2. 23. Write a program to monitor the P2.7 bit. When it is low, send 55H and AAH to PO continuously. 24. Write a program to monitor the P2.0 bit. When it is high, send 99H to Pl. If it is low, send 66H to P1. 25. Write a program to monitor the P1.5 bit. When it is high, make a low-to-high- to-low pulse on P1.3. 26. Write a program to get the status of P1.3 and put it on P1.4