Mixing buffers and pass transistors in FPGA routing architectures
Bibliographic record
Abstract
The routing architecture of an FPGA consists of the length of the wires, the type of switch used to connect wires (buffered, unbuffered, fast or slow) and the topology of the interconnection of the switches and wires. FPGA routing architecture has a major influence on the logic density and speed of FPGA devices. Previ?ous work [] based on a 0.35um CMOS process has suggested that an architecture consisting of length 4 wires (where the length of a wire is measured in terms of the number of logic blocks it passes before being switched) and half of the programmable switches are active buffers, and half are pass transistors. In that work, however, the topology of the routing architecture prevented buffered tracks from connecting to pass-transistor tracks. This restriction prevents the creation of interconnection trees for high fanout nets that have a mixture of buffers and pass transistors. Electrical simulations sug?gest that connections closer to the leaves on interconnection trees are faster using pass transistors, but it is essential to buffer closer to the source. This latter effect is well known in regular ASIC routing [2].
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".