Design ISE uses ECS for drawing schematics. To start up ECS , go to File->New. Alternatively right-click on the project name, ToyProcessor, and select New Source. ECS Hints The ECS schematic capture program is designed around the user selecting the action they wish to perform followed by the object the action is to be performed on. In general most Windows applications currently operate by selecting the object and then the action to be performed on that object. Understanding this fundamental philosophy of operation makes learning ECS a much more enjoyable experience. Project Manager : Adding a New Source 1. From the Project menu select New Source Schematic and give it the name toZERO_sch.sch. NB: Make sure the A dd to Project checkbox is checked. This adds toZERO_sch to the list of sources in Project Manager.
New Source : Schematic : toZERO_sch.sch 2. Click Next then Finish . The ECS Schematic Editor window will now open, but it will be obscured by the Design Summary . To see the Schematic Editor , you may close the Design Summary by clicking on the X as shown in red below:
ECS : Adding Symbols to the schematic 1. In the open ECS window, click the Add Symbol tool. 2. Type nor in the Symbol Name Filter to display symbols that begin with “nor”. We want nor8. ECS schematic with the New Symbol tool selected 3. Click the nor8 gate and place it on the schematic drawing sheet using the mouse. Press Esc to exit from the symbol placement mode. ECS : Adding wires 4. Select the Add Wire tool from the Drawing Toolbar. Add a hanging wire extending outwards from each of the ports (or pins) of the nor8 symbol. Note : To add a hanging wire click on the symbol pin to start the wire, once at each vertex and then double-click at the location you want the wire to terminate. Note : Click once on the symbol pin, once at each vertex and once on the destination pin to add a wire between two pins. ECS will let the user know that a net can be attached to a port by highlighting it with a red square. Your schematic should look like this:
nor8 gate with ports extended by nets (wires) ECS : Adding Net Names 5. Select the Add Net Names tool from the Drawing Toolbar (“net” is synonym for “wire”). Type zero_out in the Name textbox in the options tab of the processes window (on the left) and then place the net name on the end of the nor8 output net by clicking it. Note : To add net names to wires that will be connected to your FPGA I/Os, place the net name on the end of the hanging wire. Press Esc to exit net naming mode. 6. Your schematic should look similar to the following figure: Naming the output net ECS : Adding a bus and bus taps 7. Draw a vertical net to the left of the net extensions of the nor8 input. It should look something like this. The vertical net should be some distance away from the terminal points of the input nets of the nor8 gate.
Vertical net to be designated as bus.
You've reached the end of your free preview.
Want to read all 20 pages?
- Spring '12
- project manager, Electronic design automation, Circuit diagram, HDL Bencher