ZiLOG System 8000 - Page 266

HRM
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HRM
the Controller updates the packet with completion
status. ST, SB and DS fields are always updated unless
there is a DMA Error. Other packet fields are also
updated by the Controller for some packet commands.
The DT:PS field for the completed packet is set to
DONE.
NOTE
If a DMA error occurs, the packet and packet
status fields in the dispatch table are not
updated. The status Register ES field must be
tested by the Host after each command.
6) SR:IP is posted by the Controller. Host may be waiting
for SR:IP (polled mode) or waiting for an interrupt if
CR:EI was set in step 3.
7) Host reads SR, then issues CR:RI to reset SR:IP and
SR:IU. This must be done in polled mode as well as
interrupt mode. The Controller may post IP again as
soon as CR:RI is sent. If more than one packet was set
up before CR:WK was sent, the completed packet is
determined by looking for a DT:PS field set to DONE.
The host sets this field to IDLE, and the packet com-
mand
cycle is complete.
SMD DIAGNOSTIC START-UP SEQUENCE
All SMD diagnostics have a similar start-up procedure.
Errors encountered during this sequence will cause the diag-
nostic to display an error message and abort. The
sequence is:
1) Initialize the SMD controller. See the earlier section
that describes this process. For any errors during
this process, the diagnostic displays a message and
aborts with a· "missing device" status.
2) The SELECT packet command is issued to the disk drive
to be tested. If no drive is selected or multiple
drives are selected, a message is displayed an the
diagnostic abe>rts with a "missing device" status;
3) The SIZE packet command is issued to the disk drive to
be tested. If this dommand fails, the diagnostic
displays a message and aborts with a "test aborted"
status.
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