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6th OA Conference - Apr 2005 - Into the Depths of OpenAccess - Timing Constraints Implementation
 

6th OA Conference - Apr 2005 - Into the Depths of OpenAccess - Timing Constraints Implementation

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This presentation describes the unique, ground-breaking development of persistent SDC-equivalent timing constraints within industry-standard OpenAccess design database.

This presentation describes the unique, ground-breaking development of persistent SDC-equivalent timing constraints within industry-standard OpenAccess design database.

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    6th OA Conference - Apr 2005 - Into the Depths of OpenAccess - Timing Constraints Implementation 6th OA Conference - Apr 2005 - Into the Depths of OpenAccess - Timing Constraints Implementation Presentation Transcript

    • Into the Depths of OpenAccess: Timing Constraints Implementation Timothy J. Ehrler Senior Principal Engineer Design Technology Group Philips Semiconductors tim.ehrler@philips.com 6th OpenAccess Conference – April 2005
    • Introduction • OpenAccess coalition requested timing constraints – Change Team categorized as high priority – Constraints considered crucial • User design flow & environment migration • EDA and proprietary application development – Working group formed to address • Functional requirements specification created • Presented to and approved by Change Team – System integrator had insufficient resources to implement • Resources committed to 2.2 release completion • Philips Semiconductors volunteered resources – Essential requirement for migration within Philips • Enables 3rd party tool development in critical areas tje –OpenAccess 2005 – Development investment accelerates migration 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 2
    • Overall System Realization Process CS CA PS PIA SRA PC OpenAccess Change CRS Integration Team Timing Constraints FRS Work group Implementers PIF PMP Sched S/W UTR tje –OpenAccess 2005 UsM 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 3
    • Simple Development Plan … NOT! schedule timeline oaRule schema (2.1) tje –OpenAccess 2005 oaConstraint schema (2.2) 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 4
    • Organization & Relationships base tech design oaValue oaTechValue oaDesignValue oaObject oaTechObject oaDesignObject oaConstraint oaTechConstraint oaDesignConstraint tje –OpenAccess 2005 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 5
    • Private Subtypes & Public Types … offsetT s s Subtype e Value Type e Value q q stS u 0x0 tT u T e e stS+1 n 0x1 tT +1 n T+1 t t stS+2 i 0x2 tT +2 i T+2 a a l l • Defined private subtypes identify internal data – Sequential within class of data • Offset added yields enumerated public types – Sequential within class of data – Offset is the value of first type tje –OpenAccess 2005 • Public types visible to applications Must be consistent among releases for compatibility 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 6
    • … and Enforced Compatibility Subtype Value Type n Value s stS e 0x00 tS o T q n stS+1 0x01 tT+1 - T+1 u stS+2 e 0x02 tT+2 s T+2 n e stS+3 0x03 tT+3 q T+3 t stS+4 i 0x04 u a tT+4 e T+12 stS+5 0x05 n l tT+5 T+13 t stS+6 0x06 i stS+7 0x07 tT+6 a T+15 tT+7 l T+16 stS+8 0x08 stS+9 0x09 tje –OpenAccess 2005 tT+8 T+18 tt+9 T+19 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 7
    • Virtual Persistence pubic class private class data tables data storage visible to manipulates object data persistent application oaValue resident oaValueTbl data data oaTechValue oaTechValueTbl API object table object data table database oaDesignValueTbl storage oaDesignValue oaTimingValue oaTimingValueTbl tje –OpenAccess 2005 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 8
    • Constraint Object Implementation • Prerequisite related element creation – Constraint related value objects – Constraint parameter definition objects – Constraint definition objects – Constraint objects – Design logic related objects – Clock related objects • Classified constraint categories – general - simple value applied to a logic point – edge – general constraint with state transition – clock related – edge constraint relative to clock with state transition – path - constraint applied to logic path with state transitions tje –OpenAccess 2005 – driver - driving signal applied to design object 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 9
    • Design Logic Paths ( , ) otA ( ) ( ) onC oitD SET D Q oitB ( , ) CLR Q • Path points - unordered array of points on a logic path • Logic points - path points with state transitions tje –OpenAccess 2005 • Logic path - ordered array of logic points 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 10
    • Clocks & Waveforms design logic oaWaveform oaClock oaClock (created) (derived) • “conventional” clock waveform • divided – divided source frequency – logical - only ‘0’ & ‘1’ transitions • multiplied – multiplied source frequency – ideal - ‘0.0’ edge transition time • edge – subset of source edges – circular - 1st edge start is last edge • shifted edges – shifted subset of source end edges • Complex waveforms for future use 1 1 1 0 multiplied HiZ ? 0 divided tje –OpenAccess 2005 0 1 ideal & logical complex 1 0 shifted edges 0 edges 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 11
    • Unit Testing • Test approach to reuse source distributed test cases – Modify, enhance, adapt, copy existing test benches – Avoid development “from scratch” – consistent testing – Provides regression test capability • Test objectives: – Ensure no errors introduced into otherwise stable areas – Verify new elements don’t impact similar existing ones – Verify expected functionality of new elements – Confirm suspected existing issues • Testing scope covers: – Data value classes – Clock and waveform classes – Logic path and related classes tje –OpenAccess 2005 – Timing constraint and definition classes 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 12
    • Test Case Coverage Test Case Test Case Verification Usage State oaConstraint Unchanged No regression oaConstraintDef Unchanged No regression New constraint definitions oaConstraintParam Unchanged No regression oaConstraintParamDef Unchanged No regression New constraint parameter definitions oaValue Modified No regression New value types oaClock New New clock and waveform objects oaLogicPath New New logic path objects oaDesignConstraint New New constraints tje –OpenAccess 2005 oaSimpleConstraint Modified Confirm other test case failure 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 13
    • Delivery • Deliverables catagorized: – project documentation - documents used to provide visibility into planning and development – development aids - applications and test cases used to assist in the development of the product – product documentation - documents that define, and otherwise specify, the interface, use model, and other application related information of the developed product – product source code - source code employed to implement the reference implementation of the developed product • Specific delivery on 1 March 2005 – Test cases tje –OpenAccess 2005 – Unit test report – Development source code 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 14
    • Summary & Recommendations • Extensive preparation mandatory – Change in philosophy from rules to constraints • Significant impact on task priorities & resources • Ensure resource availability – Expect less availability, effectiveness than assumed • Heavy impact on development and delivery – Provide contingency for alternate resources • Stay closely involved with integrator (Cadence) – Any questions or concerns – ask them! – Review implementation with them as it develops – Code reviews work – consult early and often tje –OpenAccess 2005 6th OpenAccess Conference, Timothy J. Ehrler, Philips Semiconductors, April 2005 15