Stephen Lau IEEE P1149.7, a complementary superset of the IEEE standard Squeezing the power out of a Debug and Test Interface (DTI)

Stephen Lau - 12/03/07TI Public Data2 Agenda What is IEEE P1149.7? What are the benefits? How is it added to my system? How does it work? Summary

Stephen Lau - 12/03/07TI Public Data3 What is IEEE P1149.7? What is IEEE (JTAG)? Connection for manufacturing test (BSDL) Connection for debugging software

Stephen Lau - 12/03/07TI Public Data4 Standards Focus vs. P Test Apps Compliance: Preserving boundary scan for System on a Chip (SoC) Capability: Features for debug Boundary Scan: Finding card level connectivity issues P1149.7

Stephen Lau - 12/03/07TI Public Data5 What is IEEE P1149.7? What is IEEE (JTAG)? Connection for manufacturing test (BSDL) Connection for debugging software What is IEEE P1149.7? A new IEEE standard currently in process P is not a replacement for P uses as its foundation P provides extensions P provides 2-pin operating modes

Stephen Lau - 12/03/07TI Public Data6 P History and Status MIPI Origins Objective – define a backwards compatible minimum pin debug interface Strategy – requirements gathering, technical debate Tactics – solicit competing proposals, choose a winner Result – P was handily selected as winning proposal vs. SWD Collaboration with Nexus consortium Objective – Compare common needs, explore common solution Strategy - Joint meetings, compare requirements Tactics - Specifications reviewed, incorporate feedback Result – Agreement to pursue IEEE standard because of large field of use IEEE PAR approved Test, Debug, and backwards IEEE compatibility considerations Specification reviewed and revision underway now Presumed Result – IEEE standard in early 2008

Stephen Lau - 12/03/07TI Public Data7 What are the benefits? Operate with fewer pinsFewer pins required for debug/test Add instrumentation using the same pinsApplication level debug TAP power managementReduce power consumption Provide framework for diverse debug technologiesImprove compatibility Preserve gateway to debug of SI errors/defectsMaintain capabilties SI IPRe-use proven technology Software IPRe-use proven technology Debug and Test ToolsRe-use proven technology Pin protocols other than those supporting scanSupport for existing technology Mix and match legacy/new IPBackward compatible Equal treatment for all industry IPSupport for existing technology Innovation / Customization Preserve Investment Do more with less Innovation / Customization Preserve Investment FeatureBenefit

Stephen Lau - 12/03/07TI Public Data8 Extending JTAG SW Driver Emulator TCLK TMS TDI TDO TCLK TMS TDI TDO TCLKTMSTDITDO Core A EMU0 EMU1 EMU0TCLKTMSTDITDO Core B EMU1EMU0 EMU1 JTAG Pins Required=6

Stephen Lau - 12/03/07TI Public Data9 Extending JTAG SW Driver Emulator TCLK TMS TDI TDO TCLK TMS TDI TDO TCLKTMSTDITDO Core A IEEE example: Data path is from TDI through cores and out TDO. EMU0 EMU1 EMU0TCLKTMSTDITDO Core B EMU1EMU0 EMU1 Read Mem 0xcoffee JTAG Pins Required=6 Communication (4) Instrumentation (2)

Stephen Lau - 12/03/07TI Public Data10 Extending JTAG SW Driver Emulator TCLK TMS TDI TDO TCLK TMS TDI TDO TCLKTMSTDITDO Core A TCLK TMS TDI TDO TCLK TMS TDI TDO Use adapters to prototype with existing IEEE HW and SW. IEEE starts in mode for compatibility. Switch the Adapter to IEEE mode by sending a command. EMU0 EMU1 EMU0 EMU1 EMU0TCLKTMSTDITDO Core B EMU1EMU0 EMU1 EMU0 EMU1 Mode=JTAG Mode=advanced TMSTMSC Switch to TMS is now TMSC. TDI and TDO are now optional. JTAG Pins Required=6 JTAG Pins Required= 4 Optional signal

Stephen Lau - 12/03/07TI Public Data11 Extending SW Driver Emulator TCLK TMS TDI TDO TCLKTMSTDITDO Core A TCLK TMS TDI TDO TCLK TMS TDI TDO EMU0 EMU1 EMU0 EMU1 EMU0TCLKTMSTDITDO Core B EMU1EMU0 EMU1 Mode=Advanced TMSTMSC EMU0 and EMU1 are typically used for to gather large amounts communication with a target application Using Background Data eXchange (BDX) and Custom Data eXchange (CDX), target information can be transferred. For maximum compatibility, CDX can be used to carry manufacturer defined protocols. 0xcoffee Pins Required= 4 Pins Required= 2

Stephen Lau - 12/03/07TI Public Data12 Extending SW Driver Emulator TCLK TMSC TDI TDO TCLKTMSTDITDO Core A TCLK TMS TDI TDO EMU0 EMU1 EMU0TCLKTMSTDITDO Core B EMU1EMU0 EMU1 Mode=Advanced TMSTMSC Pins Required= 2

Stephen Lau - 12/03/07TI Public Data13 IEEE P Connection Topologies When all chips have Class 4 or Class 5 TAPs the 4-pin topologies may be operated as a 2-pin topology

Stephen Lau - 12/03/07TI Public Data14 Key Control Concepts Extend functionality of BYPASS and IDCODE instructions (overload these instructions) Keep new command structure invisible to existing TAPs Create commands without using TDI or TDO Use commands to create registers without changing IR/DR scan paths

Stephen Lau - 12/03/07TI Public Data15 Overloading the Bypass Instruction (using Zero-bit DR-Scans (ZBS)) IR register set to BYPASS or IDCODE instruction by: IR-Scan or Test-Logic-Reset ZBS = Capture Exit Update The number of consecutive ZBSs are counted to create a control level that specifies the overloaded function This is performed by standard IEEE TAP controller state sequences Method: BYPASS IR Register

Stephen Lau - 12/03/07TI Public Data16 Zero-Bit Scans Create Control Levels Count the number of Zero- Bit-Scans (ZBS) to change the definition of BYPASS instruction. Lock control level when the Shift-DR state is reached. Key: 1…. 2…. 3…. Lock Control Level at 3. BYPASS IR Register

Stephen Lau - 12/03/07TI Public Data17 Creating a Control Level Example: Steps to create a control level 3 1.IR-Scan with BYPASS instr. 2.ZBS 3.ZBS 4.ZBS Example: Steps to create a control level 5 1.IR-Scan with BYPASS instr. 2.ZBS 3.ZBS 4.ZBS 5.ZBS 6.ZBS BYPASS instruction Increment control level from 0 to 1 Increment control level from 1 to 2 Increment control level from 2 to 3 BYPASS instruction Increment control level from 0 to 1 Increment control level from 1 to 2 Increment control level from 2 to 3 Increment control level from 3 to 4 Increment control level from 4 to 5

Stephen Lau - 12/03/07TI Public Data18 SW directed mode switches between JTAG modes and advanced modes. Software drivers always use IEEE state sequences. Framework for multiple debug and other technologies IEEE Debug and Test Tech. Binder All industry debug and test IP co-exists behind a standard Interface Debug/Test Framework Applications TAPs Boundary Scan JTAG Bulk Data Transfer Instrumentation Sources Custom Data Transfer BDM (Freescale)/ SWD (ARM)/other BDX CDX Test Test and Private Interface Modes Power Power down test logic when not used Narrow (2) or Wide (4) Standard interface benefits tools suppliers and users IEEE signaling used at start-up SW directed mode switches between JTAG modes and advanced modes

Stephen Lau - 12/03/07TI Public Data19 Deployment Profiles Flash, CPLDs, FPGAs Minimal SOC or Micro-Controller Moderate Sophisticated SOC Most Deployment Profile Test Test and private interface modes Specialty functions Power Chip power and reset controller managing interface power Every microwatt counts Shift_DR state may be used to overlay any custom protocol CDX Extensibility (non-JTAG functions) Pause and Idle states provide instrumentation channel BDX Pin and BW Utilization JTAG Optimized serialization of TMS, TDI, Ready, and TDO Multiple formats

Stephen Lau - 12/03/07TI Public Data Classes IEEE Extensions Class T0 – Assure IEEE Compliance for chips with multiple TAPs Class T1 – Add control functions (e.g. functional reset, power) Class T2 – Add performance features for series Class T3 – Add Star configuration Advanced Two-Pin Operation Class T4 – Add two pin operation Class T5 – Add instruction/custom pin use to two pin operation

Stephen Lau - 12/03/07TI Public Data21 IEEE Summary Do More with Less: Lower pin count Remaining backwards compatible with Si IP and Tools Gain additional debug capability

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Stephen Lau - 12/03/07TI Public Data23 IEEE Classes Ensure compliance with to enhance compatibility with industry test infrastructure 4 Power Down modes friendly to: Board Test, Chip Test, and Application Debug Chip Level Bypass Built-in Chip Select Mechanism 2 pins provide scan, Test-Logic-Reset (TLR), and instrumentation (serialized transactions) Download specific modes (Target Input only) 2x Clock rate and optimized transactions Concurrent Debug and Instrumentation using same pins Instrumentation of data passed during Run-Test- Idle, Pause-DR, and Pause-IR states Custom technologies can use the test access port pins in Shift-DR state. (ex: SWD, BDM, etc. ) After Test-Logic-Reset (TLR) multi-TAP devices: Conform to mandatory instruction behavior 1-bit DR-Scan for bypass instruction Addresses stacked die and multi-chip module needs Power: Test logic power-down, etc. Performance: Shorten multi-chip scan chains with 1-bit IR bypass Glue-less star configuration Pins: Less pins and more functions Faster downloads to target Equivalent performance with fewer pins Instrumentation (BDX) Customization (CDX) Class T0 Class T1 Class T3 Class T4 Class T5 Class T2

Stephen Lau - 12/03/07TI Public Data24 Chip logic Existing Si IP Narrow (2-pins) or Wide (4-pins) P – Adds capability to Minimizing Changes/Maintaining Performance IEEE added No changes to existing Si IP Emulator logic Existing controller IEEE added May be added to existing controller 20 MHz 40 MHz The same or better performance than IEEE may be achieved in some cases With advanced protocol Falling–edge to falling edge timing allows doubling TCK rate The amount of information transferred is minimized to boost performance Two or less bits are transferred/TAP controller state in some cases If a device supports SSCAN modes, performance can improve more. = the same TCK/TAP state rate as IEEE bits/TAP state 2*TCK rate 1.7 bits/TAP state = 1.17X the TCK/TAP state rate as IEEE bits/TAP state = 2X the TCK/TAP state rate as IEEE bits/TAP state = 1.3X the TCK/TAP state rate as IEEE

Stephen Lau - 12/03/07TI Public Data25 Series Bypass Uses TAP selection and bypass bit to: improve series conneted devices scan performance using 1-bit chip bypass for very long scan chains Create a firewall to protect system operation when DTC is connected or disconnected from the TS 38-bit IR24-bit IR16-bit IR 6-bit IR 1-bit bypass 1-bit bypass 6-bit IR Chip Level Bypass I want to access this one! Total Chain =100 Total Chain =8 TAP1TAP2TAP1TAP2TAP1 TAP1 and TAP2 frozen in IDLE state.

Stephen Lau - 12/03/07TI Public Data26 Situation at Power-Up At power up, you can have the bypass as the default (JScan1 scan format) Protects TAPs from spurious signal Prevents core corruption during hot connections Command sequence makes TAPs visible. Command sequence is transparent to IEEE devices allowing a mix of IEEE and IEEE devices. 1-bit bypass 1-bit bypass 6-bit IR TAP1 TAP1 and TAP2 frozen in TLR state. 38-bit IR24-bit IR16-bit IR 6-bit IR TAP1TAP2TAP1TAP2TAP Device Device Device Device Configuration at Power UP Configuration after firewall lowered.