Viewing the Routed Design
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Introduction to Viewing Routed Designs
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Today, weβre going to discuss what happens after routing in ASIC design. Can anyone tell me what they think a routed design includes?
I think it includes all the connections between the cells.
Exactly! A routed design displays all these connections. It also shows where the standard cells are placed and how the power networks are arranged. Why do you think this visualization is important?
It helps verify that everything is connected correctly and that power distribution is adequate.
Right! Ensuring that power and connections are correct is crucial for the chip's functionality. Letβs remember: 'Placement precedes performance'.
Elements of a Routed Design
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Now, letβs look at the key elements found in the routed design. Can anyone list what these elements are?
We have the standard cells, power networks, and metal interconnects.
Great! What function do you think the power networks serve in the design?
They provide power to the cells, right? Without them, the chip wouldn't work at all.
Correct! VDD and GND networks must be properly designed to minimize power issues. What challenges might arise if these networks are not well planned?
There could be voltage drops or uneven power distribution leading to malfunction.
Exactly! Just remember, 'Without power, there's no performance!'
Analyzing the Visual Layout
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When we examine the layout viewer, what details will we look for to confirm the designβs integrity?
We check that all connections are made according to the netlist.
Correct! We also need to ensure that the design follows the physical design rules. What might those be?
Things like minimum width and spacing of the wires!
Exactly! If we violate these rules, it could lead to manufacturing defects. Always ask: 'Is it manufacturable?'.
Introduction & Overview
Read summaries of the section's main ideas at different levels of detail.
Quick Overview
Standard
This section details the process of viewing a routed design in an ASIC layout viewer, explaining how this visual representation shows the arrangements of standard cells, power networks, and metal interconnects, which is crucial for ensuring manufacturability and validity of the design.
Detailed
Viewing the Routed Design
After completing the routing process in ASIC design, the resultant layout can be visualized using a layout viewer, which serves as a comprehensive representation of the entire chip design. This layout showcases various elements including:
- Placed Standard Cells: The fundamental building blocks of the ASIC, arranged in rows.
- Power Networks: The VDD (positive power supply) and GND (ground) networks which are crucial for the functionality of the design.
- Metal Interconnects: The intricate wiring that connects different cells over multiple metal layers, illustrating the complexity and interdependencies of the design.
This visual representation is essential for evaluation against manufacturing requirements, ensuring that the design can be feasibly realized in silicon while also functioning as intended.
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Overview of the Routed Design
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Chapter Content
After routing, the entire design can be viewed in a layout viewer. This provides a detailed, full-chip visual representation, showing all the placed standard cells, the VDD/GND power networks, and the intricate network of metal interconnects spanning multiple layers. This is the closest representation to what will be physically manufactured.
Detailed Explanation
Once the routing phase in ASIC design is complete, the next step is to visualize the entire chip layout using a specialized layout viewer tool. This viewer showcases the final design. Here, you can see all the components, including individual standard cells, which are the basic building blocks of the circuit. Additionally, the VDD (power supply) and GND (ground) networks are displayed, visualizing how power is distributed across the chip. Furthermore, complex interconnections made from metal layers are highlighted, illustrating how the various parts of the chip are wired together. Ultimately, this visual representation serves as a detailed guide for the manufacturing process, providing a blueprint that approximates how the chip will actually look and operate once fabricated.
Examples & Analogies
Think of the routed design as the architectural blueprint of a large building. The layout viewer is like a detailed map that shows everythingβrooms (the standard cells), electrical systems (the VDD/GND networks), and the intricate pathways (the metal interconnects) connecting all these areas. Just like how builders use blueprints to construct a building, manufacturers use this routed design to physically manufacture the ASIC chip.
Key Concepts
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Routed Design: The complete layout representation of an ASIC, showing placements and connections.
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Standard Cells: Building blocks of ASICs, providing modular design and reproducibility.
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Power Networks: Critical for supplying consistent voltage to the ASIC.
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Metal Interconnects: Facilitate communication between components in the ASIC layout.
Examples & Applications
An ASIC layout viewer shows the power grid, clearly indicating VDD and GND lines along with connections for standard cells.
In checking a routed design, visual indicators might reveal areas of potential congestion where too many wires crowd a space.
Memory Aids
Interactive tools to help you remember key concepts
Rhymes
Routed designs, power lines, make your chips truly shine.
Stories
Imagine building a city; the standard cells are the buildings, power networks are the roads supplying energy, and metal interconnects are the highways connecting them all together.
Memory Tools
Remember the acronym 'PEM' for Routed designs: Power networks, Elements (standard cells), and Metal interconnects.
Acronyms
Use 'S-P-M' to recall the key elements
**S**tandard cells
**P**ower networks
**M**etal interconnects.
Flash Cards
Glossary
- Routed Design
The complete layout of an ASIC design incorporating all placements of standard cells and their interconnections via metal layers.
- Standard Cells
Pre-designed logic elements like gates and flip-flops used in ASIC designs for efficient placement and routing.
- Power Networks
The system of VDD and GND connections that provide power to the placed standard cells in an ASIC.
- Metal Interconnects
Metal layers used to connect standard cells together following the design's netlist.
Reference links
Supplementary resources to enhance your learning experience.