ch7_物理设计

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输入 输出 三态 双向
ROM RAM 专用模块(如ASSP、DSP等) Black box商业IP(如ARM、标准单元等) 模拟模块(如PLL、振荡器等)
P10
Data Setup
Physical Reference Libraries
P11
Data Setup
P7
Data Setup
后端设计数据准备
设计网表 设计约束文件 物理库文件 时序库文件 I/O文件 工艺文件 RC模型文件 gate-level netlist SDC file sc.lef/io.lef/macro.lef sc.lib/io.lib/macro.lib I/O constraints file(.tdf) technology file(.tf) TLU+
A physical design, or layout, is the result of a synthesized netlist that has been placed and routed
P49
Create Physical-only Pad Cells
Physical-only pad cells (VDD/GND, corner cells) are not part of the synthesized netlist Must be created prior to specifying the pad cell locations
电压钳位单元(tie-high/tie-low) 二极管单元(diode),对违反天线规则的栅输入端加入反偏二 极管,避免天线效应将栅氧击穿 时钟缓冲单元(clock buffer/clock inverter):为最小化时钟 偏斜(skew),插入时钟缓冲单元来减小负载和平衡延时 延时缓冲单元(delay buffer):用于调节时序 阱连接单元(well-tap cell):主要用于限制电源或地与衬底之 间的电阻大小,减小latch-up效应 电压转换单元(level-shifter):多用于低功耗设计
target_library link_library
P9
Data Setup
逻辑单元库:一个完整的单元库由不同的功能电路所组成 ,种类和数量很多,根据其应用可分为三类:
标准单元(standard cells)
模块宏单元(macro block)
组合逻辑 时序逻辑
输入输出单元(I/O pad cell)
P50
Specify Pad Cell Locations
P51
Initialize the Floorplan
P52
Core Area Parameters
P53
Floorplan After Initialization
Create a floorplan that is likely to be routable and achieve timing closure
P48
ICC Terminology
Design planning is the iterative process of creating a floorplan。 A chip-level floorplan entails defining:
• • • •
Core size, shape and placement rows Periphery: IO, power, corner and filler pad cell locations Macro cell placement Power grid (rings, straps, rails)
物理单元库:和逻辑单元库分类相同,但也包括一些特殊 单元,在后端物理实现中的作用有别于其它逻辑电路
填充单元(filler/spacer)
I/O spacer用于填充I/O单元之间的空隙以形成power ring 标准单元filler cell与逻辑无关,用于把扩散层连接起来满足DRC规 则和设计需求,并形成power rails
P36
General IC Compiler Flow
P37
Design Planning
P38
Load an Existing Floorplan
P39
Placement and Related Optimizations
P40
Clock Tree Synthesis
P41
Routing
第7章 物理设计—— 基于ICC的数字IC后端设计
P1
概述
物理设计是把电路信息转换成foundry厂可用于掩 膜的版图信息的过程,它包括数据准备、布局、 时钟树综合、布线及DRC、LVS等步骤。 常用的布局布线工具有Synopsys公司的IC Compiler、Astro。 IC Compiler是一个单独的、具备收敛性的、芯片 级物理实现工具,集扁平化及层次化设计规划、 布局和优化、时钟树综合、布线、可制造性及低 功耗众多功能于一体,使设计人员能够如期完成 当前的高性能、高度复杂的设计实现。
P42
Chip Finishing
P43
Analyzing the Results (1/2)
P44
Analyzing the Results (2/2)
P45
Example “run” Script
P46
Unit2
P47
Design Planning
芯片设计的物理实施通常被简称为布局布线( P&R,Place-and-Route),而P&R之前的大 量工作,包括Data Setup、Floor-plan、 power-plan亦非常关键。 布图规划的主要内容包括芯片大小(die size) 的规划、I/O规划、大量硬核或模块(hard core、block)的规划等,是对芯片内部结构的 完整规划和设计。 布图规划的合理与否直接关系到芯片的时序收 敛、布线通畅(timing and routability)。
P27
6. Define Logical Power/Ground Connections
P28
7. Apply and Check Timing Constraints
P29
8. Ensure Proper Modeling of Clock Tree
P30
9. Apply Timing and Optimization Controls
P2
High-Level IC Compiler Flow
P3
Lab 0: IC Compiler GUI - MainWindow
P4
Lab 0: IC Compiler GUI - LayoutWindow
P5
Unit1
P6
ห้องสมุดไป่ตู้
Data Setup
布局布线的准备工作,读入网表,跟Foundry提供 的STD Cell、Pad库以及Macro库进行映射。
Number and name designations for each layer/via Physical and electrical characteristics of each layer/via Design rules for each layer/Via (Minimum wire widths and wire-to-wire spacing, etc.) Units and precision for electrical units Colors and patterns of layers for display …
P17
3a. Read the Netlist and Create a Design CEL
P18
What Does unlqulfy Do?
P19
3b. Shortcut: Import the Netlist
P20
Data Setup
The Technology File (.tf file):The technology file is unique to each technology; Contains metal layer technology parameters:
P12
Data Setup
库文件
时序库:描述单元库中各个单元时序信息的文件。( .lib库)
单元延时 互连线延时
物理库:是对版图的抽象描述,她使自动布局布线成 为可能且提高了工具效率(.lef库),包含两部分
技术LEF:定义布局布线的设计规则和foundry的工艺信息 单元LEF:定义sc、macro、I/O和各种特殊单元的物理信息 ,如对称性、面积大小、布线层、不可布线区域、天线效应参 数等。
Timing is Based on Cell and Net Delays
P24
Mapping file
P25
5a. Check the Libraries
P26
5b. Verify Logical Libraries Are Loaded
Note: The list_libs command can only be executed after a netlist has been read in.
P8
Data Setup
Logical Libraries
Provide timing and functionality information for all standard cells (and, or, flipflop, …) Provide timing information for hard macros (IP, ROM, RAM, …) Define drive/load design rules:
open_mw_cel DESIGN_data_setup create_cell {vss_l vss_r vss_t vss_b} pv0i create_cell {vdd_l vdd_r vdd_t vdd_b} pvdi create_cell {CornerLL CornerLR CornerTR CornerTL} pfrelr
P21
4. Specify TLU+ Parasitic RC Model Files
TLU+ is a binary table format that stores the RC coefficients
P22
Timing is Based on Cell and Net Delays
P23
Max fanout Max transition Max/Min capacitance
Are usually the same ones used by Design Compiler during synthesis Are specified with variables:
P13
Data Setup
Milkyway Structure of Physical Libraries
P14
1. Specify the Logical Libraries
P15
IC Compiler Initialization Files
P16
Create a “Container”: The Design Library
P31
10. Perform a „Timing Sanity Check‟
P32
11. Remove Unwanted “Ideal Net/Networks”
P33
12. Save the Design
P34
UNIX Manipulation of a Milkyway Database
Instead, use the commands rename_mw_cel, copy_mw_cel, remove_mw_cel. They are Milkyway-aware, UNIX is not.
P35
Loading an Existing Cell After Exiting ICC
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