XDM and xmake Instructions

xmake

The xmake program is perhaps the easiest way to do the physical design for a Xilinx part. It works like UNIX make in that it knows the dependencies between different types of xilinx files. Here's how to run xmake:

% xmake -P 4013EHQ240-3 Mult1

The part, package and speed grade are specified in the 4013EHQ240-3 string. Running xmake can take sometime, so go get a snack.

After it is finished, you should look at the Mult1.out and Mult1.rpt files for the results of the xmake. In order to check the delay, you should run:

% xdelay -s Mult1.lca

Unfortunately, because the multiplier has so many paths, and this program seems to have a memory leak, you may run out of virtual memory. If this happens, we are going to take advantage of the fact that the logically longest path in almost any multiplier is from the LSB of the input to the MSB of the output. To do this you need to invoke the GUI xdelay by typing :

% xdelay

When the window comes up, load in the multiplier design by selecting Design->Design and selecting Mult1.lca in the dialog box. Next, run:

Timing->Xdelay

When the window comes up allowing you to select the options, choose

-FromIOB

A dialog box will display all the I/Os to the device. Select the a<0>, a<1>, b<0>, b<1>. Then hit Done. Next choose the option:

-ToFF

which will display all the registers in the design. You should select the registers that store the two MSBs of the product: c1<23> and c1<22>. Then hit Done. Back in the main xdelay options menu, hit Done. (Who designed this user interface anyway?) In a few minutes, it should list the longest paths between these points in the design. Save them so that you can turn in your results. If you need to do this for other designs you create, you need to defend you assumptions about what the critical path is.

XDM

XDM is the GUI interface to every Xilinx tool available for the AIX platform. The use of XDM for placing and routing a design from XNF is not recommended. xmake is the best way to accomplish that. But using XDM, or the internal editor LCAEDIT and XACT, you can view the layout of the design.