Return Setup Data (Operation Code 0D) - Adaptec AHA-1740A Technical Reference Manual

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If target mode is not enabled, the host adapter will behave on the SCSI interface as if
it were an ordinary SCSI initiator. Any attempt to select the host adapter will result
in a SCSI selection time out. Most reset operations, including Soft Reset, Hard Reset,
and Power-On Reset will return the AHA-1740A/1742A/1744 Target Mode to the dis-
abled state. SCSI resets, generated either by the host or by other SCSI devices, will
not change the previously established enabled or disabled state of Target Mode.

Return Setup Data (Operation Code 0D)

This command returns information describing the setup of the host adapter. The in-
formation returned reflects either the values supplied by previous host adapter com-
mands or default values. The command is followed by an outbound data transfer and
an inbound data transfer. The outbound transfer is a 1-byte parameter indicating the
length of the required inbound data transfer. The inbound data transfer contains
from zero to 255 bytes of information describing the setup of the host adapter. The in-
bound information normally transferred will be truncated or padded with zeros as
necessary to transfer the requested number of bytes. The number of bytes normally
transferred by the AHA-1740A/1742A/1744 is 17.
Byte Description
Outbound Data Byte
00 Data In Length
The number of data bytes
requested can be from 0 to 255.
A value of zero will be accepted
and 256 bytes will be returned.
Inbound Data Summary
00 SDT and Parity Status
01 Transfer Speed
02 Bus On Time
5-10
AHA-1740A/1742A/1744
Meaning
Bit 0 If this bit is zero, synchronous
data transfer negotiation will
not be initiated by the host
adapter, but will be responded
to if requested by an attached
SCSI device. If the bit is one,
synchronous data transfer
negotiation will be initiated by
the host adapter under those
conditions which require such
negotiation. The state is set
from jumper J1.
Bit 1 If this bit is zero, parity
checking on inbound SCSI
transfers has been
disabled. If this bit is one,
parity checking on inbound
SCSI transfers is enabled. The
state is set from jumper J1.
Bit 2-7 Reserved (0)
This byte returns the value
passed in to the host adapter by
the Set Transfer Speed
command (see Set Transfer
Speed in this chapter)
Indicates the Bus On Time in
microseconds (see Set Bus On
Time in this chapter))