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EPM240GF100A 数据表(PDF) 20 Page - Altera Corporation |
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EPM240GF100A 数据表(HTML) 20 Page - Altera Corporation |
20 / 86 page 2–12 Chapter 2: MAX II Architecture MultiTrack Interconnect MAX II Device Handbook © October 2008 Altera Corporation The Quartus II software automatically creates carry chain logic during design processing, or you can create it manually during design entry. Parameterized functions such as LPM functions automatically take advantage of carry chains for the appropriate functions. The Quartus II software creates carry chains longer than 10 LEs by linking adjacent LABs within the same row together automatically. A carry chain can extend horizontally up to one full LAB row, but does not extend between LAB rows. Clear and Preset Logic Control LAB-wide signals control the logic for the register’s clear and preset signals. The LE directly supports an asynchronous clear and preset function. The register preset is achieved through the asynchronous load of a logic high. MAX II devices support simultaneous preset/asynchronous load and clear signals. An asynchronous clear signal takes precedence if both signals are asserted simultaneously. Each LAB supports up to two clears and one preset signal. In addition to the clear and preset ports, MAX II devices provide a chip-wide reset pin (DEV_CLRn) that resets all registers in the device. An option set before compilation in the Quartus II software controls this pin. This chip-wide reset overrides all other control signals and uses its own dedicated routing resources (that is, it does not use any of the four global resources). Driving this signal low before or during power-up prevents user mode from releasing clears within the design. This allows you to control when clear is released on a device that has just been powered-up. If not set for its chip- wide reset function, the DEV_CLRn pin is a regular I/O pin. By default, all registers in MAX II devices are set to power-up low. However, this power-up state can be set to high on individual registers during design entry using the Quartus II software. MultiTrack Interconnect In the MAX II architecture, connections between LEs, the UFM, and device I/O pins are provided by the MultiTrack interconnect structure. The MultiTrack interconnect consists of continuous, performance-optimized routing lines used for inter- and intra- design block connectivity. The Quartus II Compiler automatically places critical design paths on faster interconnects to improve design performance. The MultiTrack interconnect consists of row and column interconnects that span fixed distances. A routing structure with fixed length resources for all devices allows predictable and short delays between logic levels instead of large delays associated with global or long routing lines. Dedicated row interconnects route signals to and from LABs within the same row. These row resources include: ■ DirectLink interconnects between LABs ■ R4 interconnects traversing four LABs to the right or left The DirectLink interconnect allows an LAB to drive into the local interconnect of its left and right neighbors. The DirectLink interconnect provides fast communication between adjacent LABs and/or blocks without using row interconnect resources. |
类似零件编号 - EPM240GF100A |
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类似说明 - EPM240GF100A |
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