Hardware Configuration

Before you can use the XJIO board to extend the testing of a UUT, you need to make sure all the required connections have been setup. These connections are both between the UUT and the XJIO board and within the XJIO board.

JTAG chain configuration

In order to use the XJIO board you need to connect the XJLink to the JTAG chains of both the XJIO board and the UUT. In this exercise we will use the ability of the XJIO board to add the JTAG devices of the UUT onto the end of its JTAG chain before routing the final TDO signal back to the XJLink.

Once the XJLink is connected you need to make sure the configuration jumpers are correctly placed to route the JTAG signals to the correct nets on the XJIO board.

First we will route the signals on the XJIO board from the required pins on CN1 to the board's JTAG chain:

Next, we will add the CPLD JTAG chain to the end of the JTAG chain on the XJIO board.

Finally, the XJDemo v4 board has two chains. The second chain (to the MCU) we will just route through the XJIO board to the XJLink2:

You have now completed all of the hardware configuration required to create a complete JTAG chain.

Checking the JTAG chain

The easiest way to check that your hardware setup is correct is to use the JTAG Chain Debugger, launched from the Windows Start Menu under XJTAG -> Utilities.

After launching the JTAG chain debugger you will first need to setup the pin mapping that should be used.

The XJIO board is designed to be powered using an external supply; however for this exercise you are going to use the ability of the XJLink to apply a small amount of power onto pin 1 to power the XJIO board.

As the XJIO board has a soft start function you need to configure a delay into the system to allow the time for it to power up after the XJLink power is turned on but before testing starts. This will be configured in a Test Reset Sequence.

Everything is now configured and when you run Check Chain you should see the following:

Starting Check Chain...

16 devices found
ID codes read:
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x11804043
  0x020A50DD
  0x4BA00477

Chain intact

Instruction Register length: 126

Device 1: Correct Boundary Scan Register length: 68
Device 2: Correct Boundary Scan Register length: 68
Device 3: Correct Boundary Scan Register length: 68
Device 4: Correct Boundary Scan Register length: 68
Device 5: Correct Boundary Scan Register length: 68
Device 6: Correct Boundary Scan Register length: 68
Device 7: Correct Boundary Scan Register length: 68
Device 8: Correct Boundary Scan Register length: 68
Device 9: Correct Boundary Scan Register length: 68
Device 10: Correct Boundary Scan Register length: 68
Device 11: Correct Boundary Scan Register length: 68
Device 12: Correct Boundary Scan Register length: 68
Device 13: Correct Boundary Scan Register length: 68
Device 14: Correct Boundary Scan Register length: 68
Device 15: Correct Boundary Scan Register length: 240
Device 16: Correct Boundary Scan Register length: 134

Check Chain complete

Connecting the UUT to the XJIO board I/O pins