Table of Contents
What is global routing?
Global routing is an estimate of how the routing might take place with the current floorplan and placement. It also gives and estimate of congestion. Detail route is the actual routing that takes place.
What are the types of global routing?
Netlist: Set of all nets. Congestion: Where the shortest routes of several nets are incompatible because they traverse the same tracks. Fixed-die routing: Chip outline and routing resources are fixed. Variable-die routing: New routing tracks can be added as needed.
What is the objective of global routing technique?
The goal of global routing is to route as many nets as possible while meeting the capacity constraint of each edge and any other con- straint, if specified. For example, for timing-driven routing, additional costs can be added to the routing topologies with longer critical path delays.
What is routing in VLSI?
Routing is the stage after CTS where the interconnections are made by determining the precise paths for each nets. This includes the interconnection of the standard cells, the macro pins, the pins of the block boundary or the pads of the chip boundary.
What is next stage after routing in VLSI design cycle?
Final Verification (Physical Verification and Timing) After routing, ASIC design layout undergoes three steps of physical verification, known as signoff checks. This stage helps to check whether the layout working the way it was designed to.
Which one of the model is mostly used in global routing?
Channel Intersection Graph
Channel Intersection Graph Most general and accurate model for global routing. Define a graph: – Each vertex vi represents a channel intersection CIi.
What is maze routing?
The maze-routing algorithm is a low overhead method to find the way between any two locations of the maze. The algorithm is initially proposed for chip multiprocessors (CMPs) domain and guarantees to work for any grid-based maze.
What are the goals of routing in VLSI?
Goals of Routing
- Minimize the total interconnect/wire length.
- Minimize the critical path delay.
- Minimize the number of layer changes that the connections have to make (minimizing the number vias).
- Complete the connections without increasing the total area of the block.
What is floorplan in VLSI?
A floorplanning is the process of placing blocks/macros in the chip/core area, thereby determining the routing areas between them. Floorplan determines the size of die and creates wire tracks for placement of standard cells.
What is routing in FPGA?
Routing provides connection between I/O blocks and logic blocks, and between one logic block and another logic block. Routing technique used in an FPGA largely decides the amount of area used by wire segments and programmable switches as compared to area consumed by logic blocks.