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1. BWRC IC Design Flow Winter Retreat January 11, 2000
Rhett Davis, Hayden So, Paul Husted, Fred Chen, Dejan Markovic, Kevin Camera, Brian Etscheid,
Ben Coates, Dave Wang,
Prof. R. W. Brodersen, Prof. Borivoje Nikolic
2. CMOS density now allows complete System-on-a-chip Solutions FPGA
Reconfigurable Interconnect
3. Possible Single-Chip Radio Architectures Software Radio
GOAL: Simplify System Design Process
Seek architectures which are flexible such that hardware and protocols can be designed independently
APPROACH: Minimize the use of dedicated logic Universal Radio
GOAL: Maximize Bandwidth Efficiency and Battery Life
Seek architectures which perform complex algorithms very fast with minimal energy
APPROACH: Minimize the use of programmable logic
4. A High Level View of an Industry Standard Design Flow Every step can loop to every other step
Each step can take hours or days for a 100,000 line description
HDL description contains no physical information
Different engineers handle the front-end and back-end design
5. A More Accurate Picture of the Standard Flow Architecture: Partition the chip into functional units and generate bit-true test vectors to specify the behavior of each unitTOOLS: Matlab, C, SPW, (VCC)FREEZE the test vectors
Front-End: Enter HDL code which matches the test vectorsTOOLS: HDL Simulators, Design CompilerFREEZE the HDL code
Back-End: Create a floor-plan and tweak the tools until a successful mask layout is createdTOOLS: Design Compiler, Floor-planners, Placers, Routers, Clock-tree generators, Physical Verification
6. Our Approach Pursue Seamless Automation
Formalize the concept of design flow
Develop a tool to automate these flows (icmake)
Develop an IC Design Flow based on a more “rich” input description
Simulink
Simple Floor-plan
Develop a “Rapid Prototyping” Design Flow based on a similar description to allow exploration of analog RF hardware and protocols
BEE (Greg Wright, Hayden So)
7. A Formal Definition of Design Flow Each node is a step. A step has associated with it a file or ordered list of files
A step with one or more outgoing edges is a dependency
A step with one or more incoming edges is a target. Each target has associated with it a command to update the file(s) from the dependencies
A step can contain another design flow
8. Our Current Design Flow Key Concepts:
Physical Design Hierarchy Matches Logical Design Hierarchy
Simple Floor-plan is maintained as a “companion” input view
9. Elaboration I: Mapping Simulink to Physical
10. Elaboration II: Wires and Macros Block – general layout
Module – parameterized, tiled structure
Buffer – a module with dynamically sized output buffers
VHDL – general synthesized block
Stateflow – converted to VHDL and synthesized
Lookup Table – converted to VHDL and synthesized Constant Value (connections to power rails)
Constant Shift
Compare to Zero (sign bit)
Ripper (single bit)
11. Example Macros Module(Ben Coates, Dave Wang)
Stateflow (Kevin Camera)
12. Floor-plan Merge With most floor-planning tools, the old floor-plan is thrown out if the schematic hierarchy is modified
Thus, in order to facilitate automation, we have to start thinking in terms of merging floor-plans instead of creating them
13. Minimized Floor-planning
14. Example Floorplan
15. Adding Programmable Processors To ensure correct functionality, the fundamental library and Stateflow translator were designed to be “correct by construction”, much like an HDL-based design
To verify the correctness of the fundamental library, an EPIC simulation step was added
In order to add programmable processors into this flow, we need to investigate interfaces which are also “correct by construction”
16. Project Status icmake program working but not yet generalized
Design Flow complete up to the route & verify step
All macros functional except Stateflow and Lookup Table
Debugging the Fundamental Library available: Add, Sub, Add_Sub, Reg, Reg_R, Mult, Neg, Comp, MUX, Rst_gen, En_gen available in fixed size: Var_2shift, Var_3shift
SCR1 Chip expected by March 1st, 2000
625,000 transistors, 516 module instances, 6 Stateflow, 3 Lookup, 108 Subsystems, hierarchy depth of 5
2-phase, non-overlapping clocking scheme, full-scan
Flow executes in 30 minutes
17. Goals for Spring 2000 Finish the current flow and chip
Implement a minimal energy, single phase clocking scheme (Fred Chen, Dejan Markovic)
Add programmable processor capability into the flow (Brian Etscheid)
Add more estimation & statistical reporting into the flow
18. Summary Physical Hiearchy matches Logical Hierarchy
Simulink Designers provide Floor-plan
Design Flow seamlessly automated from Simulink & Floor-plan