摘要:
A configurable SRAM for a field programmable gate array. Two memory arrays each have a data input, a data output, a write enable input and port A and B address inputs. First and second address buses are selectively coupled to the port A and port B address inputs through multiplexers such that different configurations can be achieved. The multiplexers are controlled by a dual port/single port steering signal and a x1/x2 steering signal such that the following configurations can be achieved: 32 x1 dual port; 32 x1 single port and 16 x2 single port. In dual port configurations, simultaneous read and write operations to different cells can occur. In x2 configuration, each array is operated as an independent memory with its own address input, its own data output and its own data input. In x1 single port configuration, one data input line and one data output line and one address bus are shared between the two arrays, and an extra address bit is used to steer the write enable signals and the output multiplexer circuitry such the write enable signal reaches the proper array and the data output from the array being read reaches the shared output line.
摘要:
An interface circuit for use in the layout of padframe interface circuits for field programmable gate arrays having a plurality of I/O cells each of which may be programmed as an input or an output (or both) and a programmable connection matrix which provide programmable pathways between the data output signals generated by the core array of logic blocks and I/O cells programmed as outputs and provide programmable pathways between I/O cells programmed as inputs and data input conductors going into the core array. The interface circuits are all substantially identical in structure, and each includes a sufficient number of power and ground connections to supply adequate current to the number of I/O cells the interface has. Each interface circuit also includes at least one and preferably two open spaces into which conductive paths may be laid out to carry power to the core array or carry dedicated signals to circuits other than the core which also reside on the integrated circuit. Because of the substantially identical structure of each interface and the preservation of ratios between I/O cells, power and ground connections and open slots, larger or smaller core arrays may be accommodated by cutting and pasting additional interface circuits into the layout thereby substantially decreasing design, placement and layout time and time to market for introduction of new FPGAs in a family with larger core arrays. The regular repeatable structure of RIU's simplifies software development for products within the family and as such contributes to faster "time to market".
摘要:
An interface circuit for use in the layout of padframe interface circuits for field programmable gate arrays having a plurality of I/O cells each of which may be programmed as an input or an output (or both) and a programmable connection matrix which provide programmable pathways between the data output signals generated by the core array of logic blocks and I/O cells programmed as outputs and provide programmable pathways between I/O cells programmed as inputs and data input conductors going into the core array. The interface circuits are all substantially identical in structure, and each includes a sufficient number of power and ground connections to supply adequate current to the number of I/O cells the interface has. Each interface circuit also includes at least one and preferably two open spaces into which conductive paths may be laid out to carry power to the core array or carry dedicated signals to circuits other than the core which also reside on the integrated circuit. Because of the substantially identical structure of each interface and the preservation of ratios between I/O cells, power and ground connections and open slots, larger or smaller core arrays may be accommodated by cutting and pasting additional interface circuits into the layout thereby substantially decreasing design, placement and layout time and time to market for introduction of new FPGAs in a family with larger core arrays. The regular repeatable structure of RIU's simplifies software development for products within the family and as such contributes to faster "time to market".