IBM Series 1 - Page 21

Figure 2-3 (Part 2 of 2).
Basi£ Subset--Poll !!f:,Q,!!.E §.isrnal Lin~
Signal na._l1..;.e ___ _
Poll *3
Poll prime *3
Poll propagate *3
------>
------>
------>
1
1
1
*1 Address bus bits 00-15 need only to be received in
this subset.
*2 Bidirectional data bus capability is assumed for
this subset. However, if the direction of data
flow within a device is fixed (in particular, a
read only device attachment with no write or
interrupt capability), the device need not
implement bidirectional data drivers and
receivers. But in this case, the device must
reject all commands requiring a transfer in other
than the direction implemented by the device. The
device must implement bidirectional data bus
drivers and receivers for the interrupt subset
*J
(described in the next section) •
Poll and poll prime need only be received,
logically ANDed, and redriven on the poll
propagate line to maintain continuity of the
serial poll mechanism.
2-6 GA34-0033
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