For This Lab You Will Implement Your BCD to 2421 Design As a Component, Connect It to The

Lab 7 Part 2 BCD to 2421

For this lab you will implement your BCD to 2421 design as a component, connect it to the Lab 7 part 1 schematic and download and test the design on the S3 board. A formal lab report is required for this lab and will be due at the beginning of lab next Thursday. Attach this sheet to your lab report. If you have a partner, each person must complete an independent lab report. Sign the pledge and include this signoff sheet with the lab report. In your lab report, not only develop and explain the theory of what you did, but simulate the design using the Xilinx ISE. Use the Alt Print Screen keys to past the simulation into your lab report. The theory, simulation, and actual hardware results should be compared. Also completely discuss the don’t care conditions. For example, why are certain outputs don’t cares, why do we observe the particular values for the don’t care conditions, what would be the effect if we did not use don’t care conditions, do the values we observe for our don’t cares agree with the unused code values give in the book’s Decimal codes table (Table 2-9), if not why not, etc.

1. Open the Xilinx ISE project you created in Lab 7 part 1 project using Xilinx ISE. 2. Add a new schematic named BCDto2421. (This is similar to the adding of the majority circuit in lab 6). 3. Draw only the portion of your BCD to 2421 schematic that produces output A. 4. Obtain a signoff: ______. 5. Complete the schematic. a. The Xilinx ECS does not allow two I/O markers to be connected directly together (such as is required to implement D = Z). A workaround for this is to insert a BUF component between D and Z. See Figure below. b. Gates are available with bubbles on the input. See figure below. c. It is not necessary to connect wires to named nets (i.e. wires). You may use Add  Net name to name a wire. It will then be connected to other nets with the same name. See Figure below.

6. Obtain a signoff: ______7. Check and save the schematic. 8. Close the schematic and return to the Project Navigator. 9. With “bcdto2421(BCDto2421.sch)” selected in the Sources in Project window, double click on Create Schematic Symbol under Design Entry Units. 10. Open the LabBCD.sch. 11. Redraw the LabBCD.sch so that it appears as shown below.

12. Obtain a signoff: ______13. Check the schematic for errors, save and close the schematic. 14. Use Impact to program the Spartan 3. 15. Collect and record data for each switch position.

W X Y Z W X Y Z A B C D SW3 SW2 SW1 SW0 LD7 LD6 LD5 LD4 LD3 LD2 LD1 LD0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 1 1 0 1 0 0 0 1 0 1 0 1 1 0 0 1 1 1 1 0 0 0 1 0 0 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1