Enable Target Mode Command (Operation Code 0C) - Adaptec AHA-1740A Technical Reference Manual

EISA-to-Fast SCSI Host Adapter
Byte Description
1 Interrupt Channel
Byte 2 SCSI Identifier
After completing this command, HACC will be set indicating normal completion.

Enable Target Mode Command (Operation Code 0C)

A special host adapter command (0C) enables and disables target mode. The host
adapter requires that two bytes of outbound information follow the command byte.
The information bytes contain the following information:
Byte 0
Byte 1
If the AHA-1740A/1742A/1744 does not have the Target Mode feature installed, the
host adapter will indicate an invalid host adapter command. If an attempt is made to
change from target mode while there are still target mode CCBs being processed by
the host adapter, the host adapter will post an invalid host adapter command
indication.
If the command disables Target Mode, the Logical Unit Mask byte will be ignored. If
the command enables Target Mode, the Logical Unit Mask byte must contain at least
one bit, indicating the presence of at least one Logical Unit.
The SCSI Inquiry command will provide an indication to other initiators that the
Logical Unit is installed or not installed in byte 1 of the returned inquiry data.
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bits 7-3
Bits 2-0
Enable/Disable Target Mode: This parameter specifies which operating
modes the host adapter will use. If the byte is set to 00h, the
AHA-1740A/1742A/1744 will operate only in Initiator Mode. If the
byte is set to 01h, the host adapter will operate both as an initiator
and as a processor-type target SCSI device. Any other value is invalid.
The default value after a Hard Reset, Soft Reset, or Power-On Reset
is 00h (Initiator only).
Logical Unit Mask: This parameter byte contains an 8-bit mask
indicating the Logical Units which will respond in Target Mode. Bit 7
corresponds to LU 7, and so forth. If the bit is one, the corresponding
LU will be treated as installed. If the bit is zero, the LU will be treated
as not installed.
Standard Mode Firmware Description
Reserved (0)
Interrupt channel 15
Interrupt channel 14
Reserved (0)
Interrupt channel 12
Interrupt channel 11
Interrupt channel 10
Interrupt channel 9
Reserved (0)
Binary value of SCSI
Identifier
5-9