Time Monitoring Feature - Fujitsu MCM3064SS Product Manual

SCSI BUS
Data Release Delay + Bus Settle Delay (Min)
Figure 7.18

7.6.11 Time monitoring feature

The ODD has a time monitoring feature for the SCSI bus to prevent hang-up of
the SCSI bus in the case that the TARG cannot receive a response from the INIT
in the RESELECTION or INFORMATION TRANSFER phase.
(1) Time monitoring in RESELECTION phase
The ODD monitors the time of the response (BSY signal) from the INIT in the
RESELECTION phase. When the INIT does not send the BSY signal within a
specified period, the ODD executes the timeout process (see Subsection 7.6.4) to
free the SCSI bus and then executes the retry process (see Section 6.1) of the
RESELECTION phase in "MCD3130SS, MCE3130SS, MCK3130SS,
MCM3064SS, MCM3130SS Optical Disk Drives SCSI Logical Interface
Specifications."
(2) Time monitoring in INFORMATION TRANSFER phase
The ODD monitors the timing of the ACK signal against the REQ signal in the
INFORMATION TRANSFER phase. Time monitoring is executed during the
following period:
COMMAND, STATUS, or MESSAGE phase:
Time taken from the moment of sending the REQ signal of the first byte to the
moment of completing the reception of the ACK signal of the last byte of the
phase.
7-38
Data Release Delay (Max)
Switching direction of transfer over the data bus
Deskew Delay (Max)
C156-E228-02EN