Emerson MVME147 User Manual
3
PACKET RETURN STATUS
Packet Return Status
When packets are returned to the user, they contain two status words: one
with an offset of $02 and the other with an offset of $18, as shown in the tables
below, respectively. The first table details the status codes contained in the
word at offset $02. Refer to the Interface Rules for the SCSI Firmware section in
Chapter 5 for additional information. Also, refer to the command table
returned fields.
with an offset of $02 and the other with an offset of $18, as shown in the tables
below, respectively. The first table details the status codes contained in the
word at offset $02. Refer to the Interface Rules for the SCSI Firmware section in
Chapter 5 for additional information. Also, refer to the command table
returned fields.
Status word offset $02
1508 0700
Bits 12-8 (reserved)
Bit 13 (RTE FLAG) (of interest only to the
programmer)
1 = This return was not preceded by an
interrupt and is the first return since
command entry. In this case, no RTE is
required.
command entry. In this case, no RTE is
required.
0 = This return was preceded by an interrupt
and is not the first return, therefore,
an RTE is required to continue proces-
sing from where an interrupt occurred.
Register A3 has a pointer to a register
save area (D0-D7, A0-A6).
an RTE is required to continue proces-
sing from where an interrupt occurred.
Register A3 has a pointer to a register
save area (D0-D7, A0-A6).
Bit 14 (ADDITIONAL STATUS)
1 = External status is valid.
0 = External status is not valid.
0 = External status is not valid.
Control Flags
Status Code (Refer to Table 3-1)