Example of Using a Shift Object in an Advanced Trigger Condition

You can use a Shift object to create an advanced trigger condition in which data shifts the amount you specify in the direction you specify. You can use a Shift object, for example, to shift registers and create new input patterns while running the Signal Tap Logic Analyzer without having to fully recompile your design.

In the following example, the advanced trigger condition occurs when the results of two Shift objects pass through a Bitwise Or object and the new value is compared against the value you specify. One Shift object moves the 16 lower bits of the instruction register into the upper half of the new 32-bit value, and the other Shift object moves the 16 upper bits of the address register into the lower half of the new 32-bit value. The two 32-bit values are then combined with the Bitwise Or object and the result is compared to a value you specify. The advanced trigger condition is set to trigger when the 32-bit value equals all 1's.

Figure 1. Bitwise Or and Shift Objects Example

  1. If you have not already done so, open one or more Advanced Trigger tabs.
  2. In the Advanced Trigger Condition Editor pane, right-click an empty space, and then click Insert.
  3. In the Object Properties dialog box, click the General tab.
  4. On the Object type list, select Bitwise Operator.
  5. Click the Parameters tab.
  6. On the Existing parameter settings list, select Bitwise Operator Type.
  7. On the Setting list, select Bitwise Or.
  8. In the Advanced Trigger Condition Editor pane, right-click the Bitwise Or object or Shift object, and then click Append to append a child object to the Bitwise Or object or Shift object.
  9. In the Object Properties dialog box, click the General tab.
  10. On the Object type list, select Shift Operator.
  11. Click the Parameters tab.
  12. On the Existing parameter settings list, select Shift Distance, and type 16 in the Setting list.
  13. For the Bitwise Or object, on the Existing parameter settings list, select Shift Direction, and on the Setting list, select Left. For the Shift object, specify Right.
  14. On the Existing parameter settings list, select Shift Type, and on the Setting list, select Logical.