beautypg.com

1 bus free phase, Bus free phase – FUJITSU M3093DG User Manual

Page 44

background image

Table 4.4 Signal delay times definition (3/3)

No.

Item

Time

Definition

14

Reset to
selection
time

250 ms
(recom>
mended)

The recommended maximum time after a hard RESET
condition until an SCSI target is able to respond with
appropriate status and sense data to the TEST UNIT
READY, INQUIRY, and REQUEST SENSE commands

15

Reset hold
time

25 os

The minimum time over which RST must be kept asserted

16

Selection
abort time

200 os

The maximum time required from the moment when
selection or deselection of an initiator or target is detected
until BSY is asserted

17

Selection
timeout
delay

250 ms
(recom>
mended)

The minimum time required for an initiator or target in
the selection or deselection phase to wait for a BSY
response before it starts the timeout procedure

18

Transfer
period

The minimum allowable period, during sync data
transfer, between the start of consecutive REQ pulses and
the start of consecutive ACK pulses

4.3.1

BUS FREE phase

The BUS FREE phase is used to indicate that no SCSI device is actively using the
SCSI bus, and that it is available.

SCSI devices shall detect the BUS FREE phase after the SEL and BSY signals are
both false for at least a bus settle delay.

SCSI devices shall release all SCSI bus signals within a bus clear delay after the
BSY and SEL signals become continuously false for a bus settle delay.

bus clear delay

bus settle delay

BSY

SEL

others

BUS FREE phase

4 $ 12