Compaq 470007-802 Deskpro EN Series of Personal Computers Maintenance and Serv - Page 90

6.1.4 ICH Fixed I/O Registers Port 00h, 02h, 04h, 06h C0h, C4h, C8h, CCh 01h, 03h, 05h, 07h C2h, C6h, Cah, CEh 10h-1Fh 20h 21h 24h-25h, 28-29h, 2Ch-2Dh, 30h-31h, 34h-35h, 38h-39h, 3Ch-3Dh 40h 41h 42h 43h 50h-53h 61h 70h 71h 72h 73h 74h-75h 76h-77h 81h, 82h, 83h 84h-86h, 88h 89h, 8Ah, 8Bh 8CH-8Eh 8Fh 91h-9Fh (except 92h) 92h Register Name Channel 0, 1, 2, 3 DMA Base & Current Address Regsiter Channel 4, 5, 6, 7 DMA Base & Current Address Register Channel 0, 1, 2, 3 DMA Base & Current Count Register Channel 4, 5, 6, 7 DMA Base & Current Count Register Aliased at 00h-0Fh Master PIC ICW1 Init. Cmd Word 1 Register Master PIC OCW2 Op Ctrl Word 2 Register Master PIC OCW3 Op Ctrl Word 3 Register Master PIC ICW2 Init. Cmd Word 1 Register Master PIC ICW3 Init. Cmd Word 1 Register Master PIC ICW4 Init. Cmd Word 1 Register Master PIC OCW1 Op Ctrl Word 3 Register Aliased at 20h-21h Counter 0 Interval Time Status Byte Format Counter 0 Counter Access Port Register Counter 1 Interval Time Status Byte Format Counter 1 Counter Access Port Register Counter 2 Interval Time Status Byte Format Counter 2 Counter Access Port Register Timer Control Word Register Timer Control Word Register Read Back Counter Latch Command Aliased at 40h-43h NMI Status and Control Register NMI Enable Register Real-Time Clock (Standard RAM) Index Register Real-Time Clock (Standard RAM) Target Register Extended RAM Index Register Extended RAM Target Register Aliased at 70h-71h Aliased at 72h-73h or 70h-71h Channel 2, 3, 1 DMA Memory Low Page Register Reserved Page Registers Channel 6, 7, 5 DMA Memory Low Page Register Reserved Page Registers Refresh Low Page Register Aliased at 81h-8Fh Fast A20 and INIT Register continued Compaq Deskpro EN Series of Personal Computers 6-3