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Chapter 12

Simulating PicoBlaze Code

Various tools support PicoBlaze code simulation, each with distinct strengths and weaknesses as described in Table 12-1. For example, the pBlazIDE Instruction Set Simulator (ISS) is best for simulating PicoBlaze operation during code development. As shown in Figure 12-1, the pBlazIDE ISS provides a seamless development environment where assembly code can be quickly tested with full observability. Registers, flags, and memory values appear on the graphical display. Likewise, each of these resources can be modified to enhance testing.

Table 12-1:PicoBlaze Code Simulation Options

Verification Tool

 

Strengths

Weaknesses

 

 

 

 

pBlazIDE

Ideal for rapid code development

• No modeling of custom logic attached to

 

Cycle-accurate Instruction Set

the PicoBlaze microcontroller

 

 

Simulation (ISS)

 

 

Single-step

 

 

Breakpoints

 

 

• Intimate interaction with PicoBlaze

 

 

 

registers, flags, and memory values

 

 

Code coverage indicator

 

 

Software timing

 

 

• Basic system-level simulation via file

 

 

 

I/O functions

 

 

Free!

 

 

 

 

 

ModelSim

Holistic simulation of PicoBlaze

• Requires simulator setup and stimulus

 

 

microcontroller with associated FPGA

files

 

logic

• Digital simulator, not an ideal Instruction

 

VHDL and Verilog logic and timing

Set Simulation environment

 

 

simulation

 

 

• Cycle and timing accurate with FPGA

 

 

 

hardware

 

 

 

 

 

PicoBlaze 8-bit Embedded Microcontroller

www.xilinx.com

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UG129 (v1.1.2) June 24, 2008

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Xilinx UG129 manual Simulating PicoBlaze Code