User`s guide

i.MX53 System Development User’s Guide, Rev. 1
Freescale Semiconductor 9-1
Chapter 9
Configuring JTAG Tools for Debugging
This chapter explains how to configure JTAG tools for debugging. The JTAG module is a standard JEDEC
debug peripheral. It provides debug access to important hardware blocks, such as the ARM processor and
the system bus, which can give users access and control over the entire SoC. Because of this, unsecured
JTAG modules are vulnerable to JTAG manipulation, a known hacker’s method of executing unauthorized
program code, getting control over secure applications, and running code in privileged modes. To properly
secure the system, unauthorized JTAG usage must be strictly forbidden.
To prevent JTAG manipulation while allowing access for manufacturing tests and software debugging, the
i.MX53 processor incorporates a secure JTAG controller for regulating JTAG access. The secure JTAG
controller provides four different JTAG security modes, which are selected by an e-fuse configuration. For
more information about the security modes, see the “Security” section in the “System JTAG Controller
(SJC)” chapter of the i.MX53 reference manual.
NOTE
By default all parts are shipped with security disabled.
The JTAG port must be accessible during platform initial validation bring-up and for software debugging.
It is accessible in all development kits from Freescale. Multiple tools are available for accessing the JTAG
port for tests and software debugging. Freescale recommends use of the ARM JTAG tools for
compatibility with the ARM core. However, the JTAG chain described in the following sections should
work for non-ARM JTAG tools. For more information about non-ARM tools, contact the third party tool
vendors for support.
9.1 Accessing Debug with a JTAG Scan Chain (ARM tools)
This section shows how to use the ARM tools to connect to the i.MX53 processor, using a JTAG scan
chain. The example uses the RealView ICE (RVI) and RVDS ARM tools. RVI provides the hardware
interface between the host PC and the JTAG port on the development kit (see
http://www.arm.com/products/tools/rvi-and-rvt2.php for more information). RVDS is the software
development kit that runs on the host PC. Its primary components consist of the ARM compiler, an Eclipse
based IDE, and the RealView Debugger (for more information, see
http://www.arm.com/products/tools/software-development-tools.php).
NOTE
Users must have the latest recommended ARM firmware installed on their
RVI box to be able to connect to the Cortex-A8 on the i.MX53.