Nios® V Embedded Processor Design Handbook

ID 726952
Date 11/25/2024
Public
Document Table of Contents

6.2.3.2.3.1. Basic Trigger Conditions

In basic triggering mode, the Signal Tap logic analyzer uses a processor-visible system address as the trigger to begin trace capture. To set the trigger, navigate to the Trigger Conditions column and select any added signal as the trigger.

You can specify the trigger pattern for a single wire as Don’t Care, Low, High, Falling Edge, Rising Edge, or Either Edge.

Examples of single wires are:

  • D_instr_valid
  • E_instr_valid
  • M0_instr_valid

For buses, you can select Insert Value to enter the pattern in any preferred number formats. Example of buses are:

  • D_instr_pc[31..0]
  • D_instr_word[31..0]
  • E_instr_pc[6..0]
  • E_instr_word[31..0]
  • M0_instr_pc[31..0]
  1. Pick any pipeline stage as the trigger stage and leave other stages with disabled Trigger Enable.
  2. Specify the trigger pattern of its Instruction Valid as High.
  3. Specify a trigger value on the Program Counter by referring to the application objdump file. Refer to Correlating Trace Data to Software ELF on instruction trace and objdump file.

The following example selects the M-stage as the triggering stage.

Note: Instructions during the D and E-stages are subject to pipeline flush if a software exception or branching occurs during the M-stage. Altera recommends that the M-stage be applied as the triggering stage.
Figure 109. M-Stage as Triggering Stage

Setting Up Triggering Stage based on objdump File

<Address>: <Opcode> 		<Assembly Mnemonic>
   314   : ff010113 		addi sp,sp,-16
  • *_instr_pc[31..0] to 0x314
  • *_instr_word[31..0] to 0xff010113