C2000™ MCU JTAG Connectivity Debug

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 LaunchPad™ Development Kits, incorporate onboard JTAG Emulation. The this application report provides a brief overview of JTAG implementation and explains the steps used to resolve common JTAG connectivity errors when using Code Composer Studio™ software.

If you are having problems using JTAG to communicate with the C2000™ device, TI strongly recommends that users follow this debug guide before seeking help through a platform such as TI's E2E™ forum. As part of the screening process, TI support personnel asks about your progress with this guide.

Trademarks

C2000™, LaunchPad™, Code Composer Studio™, E2E™, BoosterPack™, and Piccolo™ are trademarks of Texas Instruments.

Microsoft® and Windows® are registered trademarks of Microsoft Corporation.

All trademarks are the property of their respective owners.

1 What Is JTAG?

JTAG is named after the group that formed the industry standard for boundary scan testing of printed circuit boards (PCBs). The results of the JTAG effort were later codified in the Institute of Electrical and Electronics Engineers (IEEE) standard: IEEE Std 1149.1. Soon after introduction, the standard became very widely used, which resulted in several additional standards, including the implementation of the on-chip Test Access Port (TAP). This made JTAG the most adapted means for embedded systems development, debug, and testing. JTAG uses a 5-pin implementation in most systems:

Test Data In (TDI)
Test Data Out (TDO)
Test Clock (TCK)
Test Mode Select (TMS)
Test Reset (TRSTn)

The necessary biasing of these pins on custom board designs is found in the device-specific data sheet or from reference designs from TI.