Application Report SPRACF0–May 2018 C2000 MCU JTAG Connectivity Debug Matthew Pate and Nabil Saheb ABSTRACT The Joint Test Action Group (JTAG) protocol is a primary means of communicating with a microcontroller (MCU) during product development, emulation, and application debug. All of Texas Instruments (TI) C2000™ devices support JTAG emulation and the C2000 evaluation products, such as controlCARDs and LaunchPads, incorporate on-board JTAG Emulation. The purpose of this application report is to provide a brief overview of JTAG implementation and explain the steps used to resolve common JTAG connectivity errors when using Code Composer Studio™ software. Contents 1 What Is JTAG?............................................................................................................... 2 2 Common JTAG Emulators.................................................................................................. 2 3 JTAG Connectivity Debug Flows .......................................................................................... 3 4 Detailed Flow Step Information ............................................................................................ 6 5 References .................................................................................................................. 10 List of Figures 1 Overall Debug Flow ......................................................................................................... 3 2 JTAG Isolation Pre-Checks................................................................................................. 4 3 JTAG Debug Flow ........................................................................................................... 5 4 Windows 10™ Device Manager Showing Successful Detection of XDS100 Emulator ............................ 7 5 Target Configurations View................................................................................................. 8 6 Test Connections ............................................................................................................ 9 7 Code Composer "Debug" Button .......................................................................................... 9 List of Tables 1 Common Emulators Used With C2000 MCUs ........................................................................... 2 Trademarks C2000, Code Composer Studio, Piccolo are trademarks of Texas Instruments. Windows 10 is a trademark of Microsoft. All other trademarks are the property of their respective owners. SPRACF0–May 2018 C2000 MCU JTAG Connectivity Debug 1 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated What Is JTAG? www.ti.com 1 What Is JTAG? JTAG is named after the group that formed the industry standard for boundary scan testing of printed circuit boards (PCBs). It was later standardized as Institute of Electrical and Electronics Engineers (IEEE) IEEE Std 1149.1. Soon after its introduction, the standard became very widely used, which resulted in several additional standards, including the implementation of the on-chip Test Access Port (TAP) on-chip. This made JTAG the most adapted means for embedded systems development, debug, and testing. JTAG uses a 5-pin implementation in most systems: • TDI (Test Data In) • TDO (Test Data Out) • TCK (Test Clock) • TMS (Test Mode Select) • TRSTn (Test Reset) The necessary biasing of these pins on custom board designs is found in the device-specific data sheet or from reference designs from TI. 2 Common JTAG Emulators Table 1 lists some common emulators for the C2000 ecosystem. Table 1. Common Emulators Used With C2000 MCUs XDS100v1 and XDS100v2 XDS110 XDS200 XDS560 Price/Speed + + ++ +++ • USB Interface • USB Interface • USB Interface • Flash Programming • Flash Programming • USB Interface Features • Flash Programming • Built in Debug Probe • Built in Debug Probe • Flash Programming on many C2000 for many new TI • Code Trace Options EVMs C2000 EVMs • Texas Instruments • Texas Instruments • Spectrum Digital Manufactures • Spectrum Digital • Texas Instruments • Spectrum Digital • Blackhawk • Blackhawk • Blackhawk Additional Information can be found at theTI C2000 Tools and Software Page. 2 C2000 MCU JTAG Connectivity Debug SPRACF0–May 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated www.ti.com JTAG Connectivity Debug Flows 3 JTAG Connectivity Debug Flows The following flowcharts provide step-by-step guidance for isolating and performing common troubleshooting advice to resolve JTAG connectivity issues. If at the end of the flow there are still issues, submit questions to the TI E2E C2000 web forum for support. 3.1 Overall Debug Flow How to use these flow charts: 1. Review the steps in Figure 1and go through the High Voltage Isolation Flow first. This is important even if isolation is not a main concern, since it can have an impact on the emulation aspect of the PCB. 2. Follow the Main JTAG Debug flow chart. Once you have completed an intermediary step, return to the Main flow and continue if there are remaining issues. 3. If the problem cannot be solved after using all flow elements, submit a question to the TI E2E support forums. A list at the end of Section 4 provides information on what to include in your question for the most efficient response from TI. 4. The below flow charts are interactive\click-able. Simply hover over the flow step of interest and click to go to the detailed description of that step. Click on the section header or step number to jump back to the flow diagram. Yes Go Through Follow JTAG Issue Start Isolation General End solved? Pre-Checks Debug Flow No Post Question on TI Support Forum Figure 1. Overall Debug Flow SPRACF0–May 2018 C2000 MCU JTAG Connectivity Debug 3 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated JTAG Connectivity Debug Flows www.ti.com 3.2 High Voltage Isolation Check Flow Many C2000 applications are high power in nature. Because of this, it is desirable to isolate the power plane of the target board from the host computer while debugging. Many TI manufactured boards have isolated emulation, or have on-board options to enable it. The flow chart shown in Figure 2 is included to help identify whether isolated JTAG is present, and if so, troubleshoot common issues in these systems. There are also stand-alone emulators that provide isolation as well; this flow does not pertain to them. Isolated JTAG Debug Flow Pre Checks Yes Ensure Confirm Both EVM Check That Yes Locate User Guide Board Has Isolation Components Are And Emulation Isolation Meets TI Based EVM Associated With Implemented? Correct For ISO Have Power Were End Use EVM Enable Applicable Requirements No No No Board Has Isolation Continue To Main Debug Flow Implemented? Yes If Isolation\Emulation Is Re- Use From TI EVM Ensure Emulator Is Programmed Figure 2. JTAG Isolation Pre-Checks 4 C2000 MCU JTAG Connectivity Debug SPRACF0–May 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated www.ti.com JTAG Connectivity Debug Flows 3.3 Main JTAG Debug Flow For Debug Remove Code Check Flash Password JTAG Debug Flow Security Locations Make Passwords All 0xFFFF Check Datasheet: Yes No 1. XRSN Pull Value Using On-Board 2. TRSTn Pull Value Disconnecting Fixed? Emulator 3. JTAG Connector During\After Run Yes Distance No No Yes No Check Power Supply No Switch To An External Power Good Replace USB Cable, Fixed? Supply And Check If LED On? Different USB Port Able To Connect Yes Yes No Present On Device Reprogram Emulation No Manager(WIN)\System Fixed Install Device Driver Controller Information(OSX) Yes Yes Check Target Is TRSTn Signal No Configuration\ No Modify CCS Fixed? High At The MCU? Generate New One\ “On Connect” Action Run Integrity Test Yes Yes Yes Low Toggling Change Bootmode XRSn State Pin Config\Wait Boot Fixed? Mode End Debug Flow No High “Debug State /ost” CCS Message Check Output Of Yes Check Clock Yes Is There Another Voltages Clock On-Board Voltage Amplitude And Identical EVM That Good? Good? Regulators Frequency Correct Works Properly? No No Post Question On Forum Mention: 1. CCS Version 2. Emulator 3. Custom Or TI EVM 4. If EVM, Has It Ever Worked Figure 3. JTAG Debug Flow SPRACF0–May 2018 C2000 MCU JTAG Connectivity Debug 5 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated Detailed Flow Step Information www.ti.com 4 Detailed Flow Step Information Beginning with the Overall Debug Flow (Figure 1), decide if the High Voltage Isolation Check Flow (Figure 2) is needed or not. Once complete, go through the Main JTAG Debug Flow (Figure 3) step by step. This is a supplement list to the flow charts. This list provides more background on the directive for each step to help better understand what is to be accomplished. 4.1 Isolation Pre-Check Flow 1. TI Based EVM: If the EVM under debug is TI based then the flow will follow this branch in the flow chart. 2. Locate User Guide Associated With EVM: All TI based EVMs will have a User's Guide or Quick Start Guide that detail the features of the EVM as well as components that are critical to the correct operation of the EVM. Reviewing these up front will assist in the debug process explained in this document. 3. Board Has Isolation Implemented: Using the reference guide from the previous step, or other documentation if not a TI produced EVM determine if the board under debug has isolation circuitry implemented or not. 4. Ensure Components Are Correct For ISO Enable:Referring back to the documentation for the EVM ensure