Intro Index Section 1

Table of Contents:

Section 1 - Hardware

1.0Introduction1
1.1CPU1
1.2Memory Layout2
1.3Main Board I/O Channels3
1.4Expansion Bus I/O Channels5
1.5DMA5
1.5.1DMA Page Registers6
1.5.2DMA Initialisation7
1.6System Interrupts7
1.6.1Interrupt Levels8
1.6.2Interrupt Controller initialisation8
1.6.3NMI Mask Control9
1.7Programmable Interval Timers9
1.7.1Timer Configuration10
1.8System Status and Control10
1.8.1Port B - System Control10
1.8.2Port A - Status-1 Input/Keyboard Code11
1.8.3Port C - Status-2 Input12
1.8.4Write System Status-113
1.8.5Write System Status-214
1.8.6System Reset14
1.9Real Time Clock15
1.10Parallel Printer Port16
1.10.1Printer Data Latch16
1.10.2Printer Control Latch17
1.10.3Printer Status Channel18
1.11The Internal Graphics Adapter19
1.11.1.1Color Alpha Display21
1.11.1.2Monochrome Alpha Display23
1.11.2.1Color Graphics Display24
1.11.2.2Low Resolution (320x200) Graphics25
1.11.2.3Medium Resolution (640x200) Graphics Mode26
1.11.2.4High Resolution (640x350) Graphics Mode26
1.11.2.5IGA BIOS Modes27
1.11.3IGA Control Registers28
1.11.4IGA BIOS EGA Mode Initialization63
1.11.5Color Graphics Adpater Compatible Registers64
1.11.5.1CGA Mode Control Register64
1.11.5.2CGA Color Select Register66
1.11.5.3CGA Status Register67
1.11.5.4CGA Mode 6845 CRTC Emulation67
1.11.5.5CRTC Display Addressing67
1.11.6Monochrome Graphics Adapter Compatible Registers69
1.11.6.1MDA Mode Control Register69
1.11.6.2MDA Status Register70
1.11.6.36845 CRTC Emulation70
1.11.7Hercules Compatible Emulation71
1.11.7.1HMGA Mode Control Register71
1.11.7.2HMGA Status Register71
1.11.7.36845 CRTC Emulation74
1.12Floppy Disk Controller76
1.12.1FDC Hardware Conditions76
1.13RS232C Asynchronous Serial Port77
1.13.1Serial Channel Interface77
1.13.2Serial Channel Pin Arrangement78
1.14Parallel Printer Interface78
1.15Keyboard Interface80
1.15.1Serial Clock and Serial Data80
1.15.2Keyboard to Main Board Interface80
1.15.3Main Board to Keyboard Interface80
1.15.4Keycodes81
1.15.5Keyboard Connector81
1.16Mouse Interface82
1.16.1Mouse Connector82
1.17Joystick Interface84
1.17.1Joystick Connector84
1.18Light Pen Connector85
1.19Expansion Card Interface86
1.20Video Connector89
1.21Power Connector90
1.22Display Selector Switch Settings91
 
2.0Firmware93
2.1Power-Up Initialisation and Self Test94
2.2Power-Up Self Tests98
2.2.1Test Procedure99
2.2.2Test Methods100
2.2.3ROS Checksum Test100
2.2.4Direct Memory Access Controller Test100
2.2.5Programmable Interval Timer Test100
2.2.6Programmable Peripheral Interface Test101
2.2.7Real Time Clock Test101
2.2.8Asynchronous Communications Element Test101
2.2.9Printer Parallel Port Test101
2.2.10Mouse X and Y Count Register Test101
2.2.11System RAM Test102
2.2.12Programmable Interrupt Controller Test102
2.2.13Disk Test102
2.2.14Keyboard Interface Test102
2.3ROM Firmware Interrupts102
2.3.1Interrupt 2: Parity Error (NMI)102
2.3.2Interrupt 5: Print Screen103
2.3.3Interrupt 6: Mouse Button Control103
2.3.4Interrupt 8: System Clock Interrupt104
2.3.5Interrupt 9: Keyboard Interrupt105
2.3.5.1Special Key Actions108
2.3.6Interrupt 14: Floppy Disk Controller110
2.3.7ROS Interrupt 16: '6845 Compatible' Video I/O111
2.3.8IGA Interrupt 16: 'EGA Compatible' Video I/O121
2.3.9Interrupt 17: System Configuration136
2.3.10Interrupt 18: Memory Size136
2.3.11Interrupt 19: Disk I/O137
2.3.11.1Hard Disk Call parameters and registers140
2.3.12Interrupt 20: Serial I/O143
2.3.13Interrupt 21: Enhanced Function Interrupt147
2.3.14Interrupt 22: Keyboard I/O149
2.3.15Interrupt 23: Printer I/O151
2.3.16Interrupt 24: System Restart153
2.3.17Interrupt 25: Disk Bootstrap153
2.3.18Interrupt 26: System Clock & Real Time Clock154
2.3.19Interrupt 27: Keyboard Break Interrupt158
2.3.20Interrupt 28: External Ticker Interrupt158
2.3.21Interrupt 29: VDU Parameter Table159
2.3.22Interrupt 30: Disk Parameter Table160
2.3.23Interrupt 31: VDU Matrix Table161
2.4System RAM Variables161
2.5Non-Volatime RAM169
2.6ROS Messages170
2.6.1Non-Fatal ROS Messages170
2.6.2Fatal Messages171
 
3.0Reference Information172
3.1Language Links172
3.2Processor Memory Usage173
3.3Keyboard and Key Codes174
3.4ACE (8250) Registers176
3.5DMA Controller (8237A-4) Registers179
3.6PIC (8259-A) Command Words182
3.7Programmable Interval Timer (8253) Registers185
3.8Real Time Clock (HD146818) Registers186
3.8.1Time Calendar & Alarm Locations187
3.8.2RTC Register Locations189
3.9Floppy Disk Controller (uPD765A)191
 
Appendix 1:Mouse Software Interfaces208
Appendix 2:MS-DOS System Configuration220
Appendix 3:Country Dependent Information for MS-DOS 3.2226
Appendix 4:RS232C Connections227
Appendix 5:Printer Lead (PL-2) Wiring Specification236
Appendix 6:Power Supply Requirements237
Appendix 7:ROM Character Set238
Appendix 8:Keyboard Keycodes240
Appendix 9:Keyboard Layouts241
Appendix 10:The Linker Program (MS-LINK)247
Appendix 11:System Commands Processor (COMMAND.COM)264
Appendix 12:The DEBUG Utility Program (DEBUG)265
Appendix 13:The EXE2BIN Utility Program290
Appendix 14:The EXIT Command291
Appendix 15:The RECOVER Utility Program292
Appendix 16:The SHARE Utility Program293

Intro Index Section 1