TABLE OF CONTENTS 9. Game port 9-1 9.1 Switch and analog inputs 9-2 9.2 Mouse input 9-5 10. System firmware 10-1 10.1 System kernel 10-1 10.1.1 Power-up and CONTROL- RESET 10-2 10.1.2 Interrupt and BRK handling 10-5 10.1.3 Miscellaneous routines 10-10 10.1.4 The system monitor 10-22 10.2 Input/Output routines 10-26 10.2.1 Port 0 : 40-column display routines 10-32 10.2.2 Port 3 : 80-column display routines 10-35 10.2.3 Port 1 : Printer routines 10-38 10.2.4 Port 2 : Serial communication routines 10-43 11.
Hardware implementation 11-1 11.1 System overview 11-1 11.2 Clock generator 11-9 11.3 CPU and system buses 11-10 11.4 Program ROM control 11-13 11.5 System RAM control 11-15 11.6 Video display generation 11-20 11.7 Keyboard control 11-38 V