Data Byte 0 AT Bus Transfer Speed80-FFh Bit Custom Transfer Speed7 16-4 000 Read Pulse Width (ns) = 100001 Read Pulse Width (ns) = 150010 Read Pulse Width (ns) = 200011 Read Pulse Width (ns) = 250100 Read Pulse Width (ns) = 300101 Read Pulse Width (ns) = 350110 Read Pulse Width (ns) = 400111 Read Pulse Width (ns) = 4503 0 Strobe off time = 100ns1 Strobe off time = 150ns2-0 000 Write Pulse Width (ns) = 100001 Write Pulse Width (ns) = 150010 Write Pulse Width (ns) = 200011 Write Pulse Width (ns) = 250100 Write Pulse Width (ns) = 300101 Write Pulse Width (ns) = 350110 Write Pulse Width (ns) = 400111 Write Pulse Width (ns) = 450Due to the internal differences between the AHA-1740A/1742A/1744 and earlier hostadapters, the data is not actually used but is saved and returned in the Return SetupData command. The command is accepted only for compatibility.After completing this command, HACC is set indicating normal completion.Return Installed Devices (Operation Code 0A)This command returns information about which SCSI Targets and Logical Units(LUs) are installed on the SCSI bus. The host adapter issues the SCSI Test UnitReady command to each target/LUN combination and reports the results using eightbytes of data returned through the Data In register. A bit having a value of one indi-cates that the associated LU is installed. Each byte is associated with the correspond-ing target. Each bit within a target byte is associated with a particular Logical Unit,bit 7 indicating the presence of LU 7 and so forth. The state of the target is analyzedusing the SCSI Test UnitReady command, analyzing the returned data to determineif the addressed LU is available.EISA-to-Fast SCSI Host Adapter Standard Mode Firmware Description5-7
