Tuesday, September 22, 2009

Xilinx Chipscope

Chipscope is an excellent tool for debugging your HDL code. Unlike the simulation tools that attempt to simulate the hardware, Chipscope is code that is physically implemented in your FPGA. This allows you to physically and precisely examine the functionality of your code. Note: This is not available in the WebPack (free version) of ISE.

To use chipscope you will need to first create your chipscope cores:
1. Create a new coregen core
-- If you make a subfolder for the cores (say in a folder called "coregen" in the project directory) make sure to use the command:
--- -sd ./coregen
--- Place this command in the Command Line Options under the Synthesize properties as well as the Implement properties
--- This tells ISE to look in the subfolder called "coregen" for missing cores/modules
2. Now make the "ila" core and the "icon" core inside coregen
3. Add these cores to your project. The files to add will either be .v or .vhd depending on you language preference.
4. Next you will need to instantiate them inside your module/architecture
-- If you are using VHDL, you should just be able to instantiate the icon and ila after the "begin" statement in the architecture design.
-- If you are using Verilog, your safest bet is to instantiate it at the end of the module before the "endmodule" statement
-- Here is an example of instantiation of the icon and ila in verilog:

//Wires used to map the IOs of the ila and icon
//to the current module

//The control mechanism between the icon and ila.
//Just leave this alone
wire [35:0] chipscope_control;

//The data you will be monitoring.
//These bits can be distributed among many
//variables in your design
wire [31:0] chipscope_data;

//An optional trigger. If left unassigned,
//chipscope will by default start acquiring
//instantly and stop once memory has filled.
//I.e. you might want to trigger on a
//pushbutton switch.
wire [7:0] chipscope_trig;
chipscope_ila_v1_02_a ila(
//internal control between ila and icon

//The clock that chipscope will run at

//The data chipscope will monitor

//The event chipscope will trigger on.
chipscope_icon_v1_03_a icon(
//Internal control between ila and icon
.CONTROL0(chipscope_control) );

These instantiations can be found inside the core's .v and .vhd files. You just need to worry about the wire/signals you want to use locally in your module.


1 comment:

  1. Chipscope is a great tool, i have been using it alot. By graphically showing the signals, many information is conveniently visible.
    One down side is it cost area of FPGA and only sample a relative short period of data to be available.