JTAG is a dedicated debug port which allows hardware assisted software debugging or to recovering flash content. Colibri and all Apalis modules provide the JTAG signals through pads on the bottom of the PCB. The Colibri Evaluation Board v3.1 and later as well as the Apalis Evaluation Board come with pogo pins connecting to the JTAG pads of the module PCB. JTAG is then provided by a standard 20-pin connector (ARM JTAG 20) on the evaluation board.
On PXA based modules JTAG is the only recovery mechanism (supported by the Toradex utility Colibri Loader).
Modules powered by NVIDIA Tegra, NXP/Freescale i.MX6 or Vybrid SoC provide an internal boot ROM with various recovery capabilities. We recommend to make use of the SoC's boot ROM for recovery instead of using JTAG.
Toradex tested Lauterbach jtag solution with TK1. By default TK1's JTAG will be in boundary scan mode, to enter JTAG mode SoC needs to be restarted with TRST_N pulled low. It can be accomplished with this trace32 commands and a board reset:
SYStem.CPU TEGRAK1 DIAG 0x3404 1
more information on debugging TK1 can be found here (external blog site)
Toradex tested some debug adapters for the secondary Cortex-M4 core (Colibri VF61). The ARM KEIL ULINKpro D debug adapter in combination with ARM DS-5 development environment has proven to be working.
Our partner AntMicro documented how to use OpenOCD on Linux. OpenOCD supports various JTAG debug adapter such as the Amontec JTAGkey-tiny, Olimex ARM-USB-OCD or Olimex ARM-USB-TINY-H.
Note: On Colibri VF61 the JTAG pin JTMS is also used by the on module audio codec. When the operating system (WinCE or Linux) is started, this pin is muxed for audio codec communication use, hence the JTAG connection will break! On Linux, the pin muxing can be avoided by compiling the kernel without the audio SoC machine driver (CONFIG_SND_SOC_FSL_SAI_WM9712).
Supported JTAG adapters:
Connect your JTAG adapter to X13 of the Colibri Evaluation Board V3.1. Make sure that pin 1 of the connector connects to pin 1 of your JTAG adapter.
On the Colibri Colibri Evaluation Board V2.1 provides a JTAG interface on connector X13. The Amontec JTAGkey-Tiny pin 1 matches to the Evalboard V2.1 X13 pin 1.
For more information about the JTAG pin out see also the Evaluation Board Schematic.
Please note that Amontec JTAGkey-Tiny may not available for purchase anymore. Another option is the Olimex ARM-USB-OCD (not the ARM-USB-OCD-H !)
The two pictures below explain how to connect the cable to the Colibri Evaluation Board V2.1
The JTAG FFC cable is a standard part available at all major electronics distributors. The main parameters are:
For example the MOLEX 98266-0083
Here are some example sources (we apologize if the links happen to be outdated):
Windows 10 does not allow to install the drivers for Amontec and Olimex JTAG adapters, because the drivers are not properly signed. To overcome this issue you need to restart Windows 10 following the procedure described below:
We found problems when installing the originally linked drivers from the Amontec page under Windows 7.
Here is a link to a set of drivers which worked fine (July 13, 2011):
On some systems, there seem to be wrong drivers installed automatically. ColibriLoader will throw an error message, that no supported JTAG adapter was found. Please follow the steps below to recover from this issue: