EPM9560RC240-15 Datasheet, PDF (10/46 Pages) Altera Corporation – Programmable Logic Device Family

MAX 9000 Programmable Logic Device Family Data Sheet
Expander Product Terms
Although most logic functions can be implemented with the five product
terms available in each macrocell, some logic functions are more complex
and require additional product terms. Although another macrocell can
supply the required logic resources, the MAX 9000 architecture also offers
both shareable and parallel expander product terms that provide
additional product terms directly to any macrocell in the same LAB. These
expanders help ensure that logic is synthesized with the fewest possible
logic resources to obtain the fastest possible speed.
Shareable Expanders
Each LAB has 16 shareable expanders that can be viewed as a pool of
uncommitted single product terms (one from each macrocell) with
inverted outputs that feed back into the LAB local array. Each shareable
expander can be used and shared by any or all macrocells in the LAB to
build complex logic functions. A small delay (t_LOCAL + t_SEXP) is incurred
when shareable expanders are used. Figure 4 shows how shareable
expanders can feed multiple macrocells.
Figure 4. MAX 9000 Shareable Expanders
Shareable expanders can be shared by any or all macrocells in the LAB.
33 Row
FastTrack
Interconnect
Signals
LAB Local Array
Macrocell
Product-Term
Logic
Product-Term Select Matrix
Macrocell
Product-Term
Logic
16 Local 16 Shared
Feedbacks Expanders
10
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