A Device which has attached by means of a Broadcast address cycle which
supports normal data cycles (Cases 1,2 3 &3a), will give SS responses for
data cycles in accordance with the FASTBUS Specification Tables 5.3.2. A link
from OCC3 to ISSD
will force SS=0 for such data
cycles, where the user wishes to suppress SS responses for Broadcast
operations, as recommended in section 4.3.2 of the Specification.
A link
from OCC2 to ISSD
will force SS=0 for data
cycles following a general Broadcast only. Other combinations of SS code and
broadcast may be obtained by using a PAL to generate ISSD &IUS(2:0) from
OCC(2:0), OMS(2:0), etc..
A Device which has Attached by means of a General Broadcast (case 1) or
Pattern Select Broadcast (cases 3, 3a), will give SS responses to a secondary
address cycle as given in Fig. 4.3.2 in the Specification, regardless of the
presence of
such a link (ISSD is ignored).
A Device which has Attached by means of a Class N Broadcast (case 2), will give SS=7 to a secondary address cycle with either an unimplemented address or bad parity, regardless of the presence of such a link (ISSD is ignored).
A Device which has Attached by any other method (geographic, logical, Manufacturer defined broadcast (Case 8)), will give SS responses for data cycles and secondary address cycles in accordance with Tables 5.3.2, regardless of the presence of such a link (ISSD will suppress SS responses in the normal way but OCCx is low).
SS codes for any data cycle may be modified by driving ISSD and IUS(2:0) to
the desired values.