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Advanced Digital Circuits ECET 146 Week 3. Professor Iskandar Hack ET 221B, 481-5733 hack@ipfw.edu. This Week’s Goals. Designing a Combinational Circuit from Truth Table Introduction to the Programming Hardware Verifying a design in Hardware. Designing from a Truth Table.
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Advanced Digital CircuitsECET 146Week 3 Professor Iskandar Hack ET 221B, 481-5733 hack@ipfw.edu
This Week’s Goals • Designing a Combinational Circuit from Truth Table • Introduction to the Programming Hardware • Verifying a design in Hardware
Designing from a Truth Table • Write a Sum of Product Equation straight from the truth table • Draw the schematic from the Equation • No Need to minimize equation (the software will find the minimum solution for the Altera architecture)
Writing the Equation • Look at the Truth Table and everywhere the output is a one then you will generate a term in the Sum of Products • The term generated will depend on the values of ABCD in the table for that term. • If the value for an input is a zero then the term would contain an T-not • If the value for an input is an one then the term would contain T
Table Equivalent Terms • The Term for each of the entries is shown here
Example 1 • Write the Equation for the following table
Comments regarding Example 1 • There were 8 – ones in the table, thus there would be 8 terms in the equation • Each one will create exactly one term, that can be easily written by looking at the table and writing the term by looking at the values • Example if you look at the third line of the table A = 0, B=0, C=1, and D=0 and the output is 1. That would generate the term
Drawing Schematic • Open Altera Quartus II Software • File->New->Schematic File • Insert Inputs and inverters to create inputs for AND gates • Draw AND gates, selecting appropriate inputs for each • OR the output of the eight AND gates • Insert Output
Insert Inputs and Inverters Draw the following circuit using INPUT and Inverters and draw the wires out of each inverter as shown
Name Pins and Nets • As in previous labs name the pins A-D • Click on each wire from the inputs and name them A-D • Click on each wire from the inputs and name them Anot-Dnot
Add AND4 Gates • Insert 8 – AND4 gates (remember one AND gate per term)
Connect Inputs to AND Gates • Connect the four inputs to the AND gates according to the equation. • This is done by drawing a small wire from each input and naming it as before. • Name them according to the equations from the previous slide
Save File Click this to Create project
Creating the Project -1 First two screens take default and hit next
Device Number Part Number (EP3C16F484C6N)
Creating the Project – II (Select Device) Cyclone II Family Need a specific device EP2C20F484C7 is the chip on the board Hit OK when done
Compiling the Project • Hit the hot key on the top of the screen to start compiling your project.
The Compiler • If you did everything right thus far you should see something like this:
Compiler Reports The compiler creates a number of reports, which at this point would mean nothing to you, but you may want to explore them. Boolean EQ I/O pin info
Comments regarding errors • It is very possible that you’ll get errors on this drawing. If so look for two connections on a wire to one of the AND gate inputs. This is the most common error. This often happens on the last AND gate if the wires brought down end at the same point you draw the wire across. Just delete the wire and redraw it.
Assigning Pins - I • Open the Pin Planner to Assign the pins
Assigning Pins II • Look at the data sheet for the board and determine what your pin numbers need to be.
Assigning Pins III • Use four of the switches for the inputs • Use one of the LEDs for the output
Tristate Unused Pins Device and Pin Options
Check New Pin Assignments • Open the resource files to look at the pin assignment after recompiling. Output pins Click to look at input pins Input pin assignments
NOTE: • The following slides were copied from Lecture two and the waveforms DO NOT match this example. They are included for instructional purposes only.
Drawing Waveforms for Simulation • We now need to create a new file to hold our simulation input waveforms. This done by hitting new and selecting Other and vector waveform file (vwf)
Entering Nodes You will need to double click in the node area of the display – this will bring up the following dialog box Select Node Finder
Entering Nodes II (1) Start by selecting Pins: all (2) Then hit List (3) Move all pins to the right by hitting >> (4) Hit OK
Check if all nodes are selected • Verify in the waveform editor that all nodes are shown Inputs Output
Change Grid and End Time • Select Edit, Grid time, and change it to 50 nS • Select Edit, End time and change it to 1.6 uS
Grouping Inputs • Select all the inputs, right click, hit ‘Group’ and use inputs[3..0] for the name of the inputs, Hex as radix, and uncheck grey count
Display after Grouping + will expand group to show the individual pins - will hide individual pins
Using Count Function • Select the Group, and then hit the count button on the left side of the screen. Take the defaults (start at 0, incr by 1, End value F)
Display after Count • You should see the following after hitting OK
Save Simulation File • Up to now you should have seen that the output is neither high or low. That is because it has not been simulated yet. • In order to simulate you must first save the file as example1.vwf Leave checked
Simulate • This is the easy part – Hit the simulate button on the top of the screen. Simulate
Verify Simulation • You should have a value for the output for each input condition. • Manually determine (using techniques from ECET 111) what the output should be for each condition and verify that the output matches that.
Connect the Altera Board to the PC • Check out an Altera Board from the Lab Tech office
Connect Board to PC I • When checking out board also check out DC wall pack. Ensure that the wall pack is of the correct polarity (+ is the center, - is the outside) and is between 9 and 12 volts. • Also get a Male -> Female DB25 cable to connect between the computer and the PC
Connect to PC II • Notice the location of the connectors used, the other DB25 connector is used for experiments. DC Power connector DB25 Cable to PC