4.6.2. Powering the interface unit using a modified cable


Use this method if you are not using the Multi-ICE Version 2.1 (or later) interface unit, and you have a 20-way JTAG connector on the target.

To connect to a running target with a modified cable:

  1. Ensure that the Multi-ICE interface unit is not already powered from the target.

  2. You must make a special IDC cable to split off pin 1 (VTref), pin 2 (Vsupply) and GND.

  3. Connect a 5V power supply between Vsupply and GND to power the Multi-ICE interface unit, but do not switch it on.

  4. Connect a voltage suitable for your target to pin 1 of the 20-way Multi-ICE connector (VTref) through a 1kO resistor. Only a very small power supply current is required into VTref. You can use the same power supply for this reference voltage as that used to power the Multi-ICE interface unit if your target uses 3.3V or 5V logic. If your target runs at a lower voltage, you must apply that voltage to VTref (see Chapter 6 System Design Guidelines for more details about VTref).

  5. The JTAG input lines TDI, TMS, nSRST, and nTRST must have pull-up resistors (normal practice) and TCK must have a pull-down resistor so that when the cable is disconnected from the target these lines are in their quiescent state.

  6. Switch on the power between Vsupply and GND, and between VTref and GND. The power light on the Multi-ICE interface unit glows brightly.

  7. Configure the Multi-ICE server. You must either manually configure the server or autoconfigure using a separate test system. Leave the server running.


    Do not use autoconfigure on the target that must be debugged. Doing so resets the processor.

  8. Plug the 20-way JTAG cable into the target.

  9. Start the debugger. The debugger can then stop the processor and display the stopped state.

    To get a high-level (source code) view, you must load the symbol table for your target program into the debugger. For AXD, use File ? Load debug symbols.... For ADW or ADU, use File ? Load symbols only....

  10. Press the Go or Run button and unplug the JTAG connector to restart the system. Then exit the debugger.

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