Add Jtag Port

This document is a work in progress. It explains how to fit the internal on-chip debug (OCD) port on a Linkstation, Kuro-Box or Kuro-Box/HG to a PC interface.

Overview
You will need to open the case and solder a 2x8 pin header to the board. You also need to build or buy a JTAG interface cable.

Locate the pads
The pads are labeled CN5 and can be seen just above the serial level converter (where the yellow, orange, and red wires start to split) in this photo

Connector Pin-outs
In order to use this port, you should bridge R67.

Baulab posted cable schematics, some pictures of the assembled jtag cable, and software needed.

According to http://www.abatron.ch/Files/ManAccessCOP-2000C.pdf and http://www.freescale.com/files/soft_dev_tools/doc/user_guide/CWH-UTP-UG.pdf the following pins are used for a PPC COP/JTAG interface:

Pin Name      Description 1 TDO        JTAG Test Data Out 2 QACK       Not Needed 3 TDI        JTAG Test Data In  4  TRST       JTAG Test Reset 5 HALTED     Not Needed 6 Vcc Target 1.8 – 5.0V: This is the target reference voltage. It indicates that the target has power and it is also used to create the logic-level reference for the input comparators. It also controls the output logic levels to the target. It is normally fed from Vdd I/O on the target board. 3.0 – 5.0V: This input is used to detect if the target is powered up. If there is a current limiting resistor between this pin and the target Vdd, it should be 100 Ohm or less. 7 TCK        JTAG Test Clock 8 CKSI       Not Connected ?? 9 TMS        JTAG Test Mode Select 10  11  SRESET     Soft-Reset 12 GROUND     System Ground 13 HRESET     Hard-Reset 14  (key, which means this pin is often removed) 15 CKSO       Not Connected on the 8421 16 GROUND     System Ground

On-Chip Debug (OCD) connector
Technically, JTAG refers only to the 5 pins with JTAG in the description above (wikipedia). There is a 14-pin JTAG interface, commonly referred to as the TI standard. There is also a 20-pin JTAG interface, commonly referred to as the ARM standard. For connecting to your PC, there are two common options: parallel port and USB. Some software packages do not support USB cables.

The OCD port on the Linkstation uses an electrical standard known as JTAG/COP. The 16-pin COP header for Freescale devices is slightly different from the TI/ARM standards. Although this is signal-level compatible with the TI/ARM standards, unfortunately the pins are in a different order on the Linkstation. Therefore, you will need to build your own cable, or use some wires to manually connect the proper pins. The signals have to be buffered to protect the hardware from damage and we use a JTAG adapter (such as the Wiggler&#153;) to do this. Those with some electronics experience could build their own circuit, but there are also several inexpensive vendors.

Schematics and Software to build your own

 * Building a JTAG Interface How to build your own parallel port-JTAG interface cable.
 * http://hri.sourceforge.net/tools/

Buy one
Several inexpensive options are listed below.
 * Macraigor
 * Wiggler&#153; Parallel port version for $150.
 * usbWiggler&#153; USB version for $225.
 * Olimex (look for a local distributor to save on shipping)
 * ARM-JTAG Parallel Port to 20-pin $20. (Advertised as being Wiggler compatible)
 * ARM-USB-TINY USB to 20-pin interface $50.
 * MSP430-JTAG Parallel Port to 14-pin $15.
 * MSP430-JTAG-TINY USB to 14-pin $70.
 * Amontech
 * JTAGkey &euro;129 USB to 20-pin. Includes some nice cables.
 * JTAGkey-TINY &euro;29 USB to 20-pin.
 * eBay
 * A quick search on ebay will find many buffered JTAG cables for less than $20.