Adaptec AHA-1740A Technical Reference Manual

Also see for AHA-1740A: User manual Instructions for installing Installation guide

Contents

Table of ContentsPreface ............................................................................................................................... xiConventions...................................................................................................................... xiiChapter One - IntroductionDocument Scope.............................................................................................................. 1-1Purpose............................................................................................................................ 1-1AHA-1740A/1742A/1744 Product Features................................................................... 1-2EISA Features .......................................................................................................... 1-2SCSI Features .......................................................................................................... 1-2Board Features......................................................................................................... 1-3Configuration Diskette and Installation Guide (ASW-C174)....................................... 1-4Product Specifications .................................................................................................... 1-5Extended Industry-Standard Architecture Interface ................................................... 1-5Standard EISA Bus Electronic and Physical Interface ......................................... 1-5SCSI Interface................................................................................................................. 1-6Electrical Interface for AHA-1740A/1742A ............................................................ 1-6Electrical Interface for AHA-1744........................................................................... 1-7Internal Connector ................................................................................................... 1-7External Connector .................................................................................................. 1-8Floppy Disk Interface ..................................................................................................... 1-9Standard Electronic and Physical interface ........................................................... 1-9Connector.................................................................................................................. 1-9Radiation Immunity ....................................................................................................... 1-9Reference Documents ..................................................................................................... 1-9Chapter Two - ArchitectureHardware ........................................................................................................................ 2-1Bus Master DMA...................................................................................................... 2-2SCSI Interface and Protocol Chip (AIC-6251) ........................................................ 2-28- and 16-Bit Memory and Odd Byte Data Transfers ............................................ 2-3Bus Auxiliary Interface Chip (AIC-565) ................................................................. 2-3EISA Configuration Chip (AIC-575) ....................................................................... 2-4BMIC Bus Interface Chip (82355)........................................................................... 2-4Floppy Disk Controller (AHA-1742A Only) ............................................................ 2-4Standard Mode Firmware .............................................................................................. 2-5Mailboxes .................................................................................................................. 2-5Command Control Block.......................................................................................... 2-6Command Descriptor Block .................................................................................... 2-7Principles of Operation ............................................................................................ 2-8Task Queuing ........................................................................................................... 2-8Enhanced Mode Firmware ............................................................................................. 2-9Onboard BIOS Operation ............................................................................................. 2-11Power-Up Diagnostics .................................................................................................. 2-11v