fpga guide for beginners

FPGA Guide For Beginners

Introduction: FPGA stands for Field Programmable Gate Array .The purpose of FPGA is to develop ASIC (Application Specific IC) and used in VLSI (Very Large Scale Integration). As obvious from the name, FPGA is an arrangement of logic gates or more technically logic units which are interconnected according to the user’s requirement. The FPGA configuration is generally specified using a hardware description language (HDL). It is like a one-chip programmable breadboard. Logic blocks can be configured to perform complex combinational functions & simple logic gates like AND, OR & XOR. Well enough of these petty details now we will look forward on how FPGA are used for some small application. Using FPGAs:

There are two most popular companies which manufacture FPGAs

XILINX FPGA BOARD I

XILINX FPGA Chip

NED University Electronics Department

ALTERA'S FPGA BOARD 1

(The fig1.1 shows an FPGAs kits of both Xilinx and Altera)

• XILINX: A Pioneer in FPGA. Kits manufactured by them are more advance. Xilinx is the leader in the digital programmable logic device (PLD) market.

• ALTERA: A competitor to Xilinx, their FPGA’s are relatively less complex and easier in use

but limited in applications. Note: Both Altera & Xilinx produce FPGA chips & development Boards. The one shown in figure 1.1 are FPGA Development Boards having an FPGA chip.

Guidelines for Installation:

• As a beginner we would recommend to use Altera’s FPGAs.

• The software used for programming FPGAs are included with the kit but the user needs to set up the license.

• For Alteras’s FPGAs the software used is Quartus II.

• The company does not provide a license with FPGA board. The user needs to register on their website in order to retrieve a license.

• For beginners, the first step is to install the software QUARTUS II from the CD included in the package. You can also download the latest version from their website: www.altera.com

ALTERA’s FPGA Chip

DIP Switches for

Input LED’s For Output

Run/Program Switch

On/Off Push

Button

http://www.altera.com/�


• After signing up you can request a license from the company (Note: this whole procedure is absolutely free)

• To request the license the company would prompt you for the physical address or MAC address of your computer’ LAN card. To get Physical/MAC address, type ipconfig/all in the command prompt. For command prompt Go to (Start Button > Run ) and type cmd and then enter it.

NOW Press OK


• Check the use of license for academic use and submit your request.

• You will soon receive your license file through E-mail. Check out your inbox, copy the license file in to the Quartus II 6.0 folder( C:/program Files/Altera/Quartus60)

• Now run Quartus II 6.0 and select the option specify the valid license file.

• Click the browse tab and include the path to your license file and click OK.

• Congratulations! You have successfully set up your license.

Programming your FPGA:

MAC Address


Now you have installed Quartus II and you are ready to program your FPGA kit. Before moving on any further it is necessary that you know the methods and languages by which you can program your FPGA.

A. Hardware Description Language (HDL) The languages used for programming FPGAs are hardware description languages: 1) Verilog HDL 2) VHDL For beginners verilog HDL is used as it is much easier to understand and its constructs are similar to C/C++.

B. Schematic or Block diagram: As a start you can build your circuit by making a schematic diagram. The software itself will interpret the logic and program the FPGA.

Your Very First Example Using FPGA: The easiest way to understand is by implementing your circuit yourself. In this tutorial we would first use schematic/block diagram method and then using verilog HDL to implement the same example.

S.R Latch: Hope that the reader has some knowledge about the S-R latch (set-reset latch) here we would program the FPGA for S-R latch. STEPS: 1) Run Quartus II software


2) Select File>New Project wizard


3) Click Next


4) Make a working directory for example: C:\Program Files\Altera\Quartus\sr_latch


5) Write sr_latch (in above fig where the ‘light’ is mentioned) as a name of the project and top-

level entity 6) Click Next. If warning message displays for creating directory click Yes

7) Leave next windows blank and click NEXT


8) Now select family as Cyclone II (might be different according to your kit for details visit

www.altera.com)

http://www.altera.com/�


9) From available devices EP2C35F672C6 and Click Next>Next


10) Now click Finish

CREATING DESIGN: 11) Now press file and select NEW. This will open a window. Choose block diagram/schematic file

under the device design files tab and click OK


12) A graphitic editor window will open


13) Select Symbol Tool (having a AND Gate icon on the left panel), go to quartus60/liabraries > Primitives > Logic and then select you require gates ( here you can found logic gates with number of inputs specified.)

14) Since, sr_latch is formed using two nand gates connected in a cross linkage has shown

Make the circuit shown above


Tip: the input and output pins can be found in primitives>pin library

15) Mark or label the terminals as shown in the figure 16) Now compile your design (compiling means checking your code or design) by clicking the

(PLAY) button or go to Processing Tab > Start Compilation. 17)

18) After compilation is completed now go to Assignments tab and select Assignment editor. 19) Pin Assignment is necessary as we have about 100 Pins on the FPGA chip, but for our

application we have to choose output & input pins.


20) Choose category as pin and double click on the entry <<new>> and choose a pin from the drop

down menu. 21) Now double click on location tab and select the location for your input and output pins on

FPGA.(Detail of FPGA’s different I/O ports addresses is provided you with the kit, which is usually in .xls or MS Excel format)


22) In this example we have chosen for inputs, S-bar and R-bar as pins PIN_N25 and PIN_N26

respectively (there are 2-way switches) on the board 23) For output we have assigned Q and Q-bar as PIN_AE23(RED LED # 1) and PIN_AF23(RED

LED # 2) leds respectively 24) Now Re-compile your design as explained in Step # 15

Dumping a Program in JTAG mode:

25) You are almost done now. To program your FPGA board, click the second last icon from the right named as Programmer or go to Tools> Programmer

26) A programmer will window open. Now select the programming mode as JTAG (also make sure

that your device should also set up for JTAG programming or set up you device by sliding a 2-way switch on the board to RUN position)


Note: There are two modes of programming into FPGA named as JTAG and AS (ACTIVE SERIAL) mode which can be selected manually by a 2-way sliding button on the board by keeping its position on RUN or PROG respectively. The only advantage of AS mode is just to keep your program save in to the flash memory of FPGA ,in this mode your program will not be lost even after turning of the device and you may be able to access it by powering up it again. 27) Select the hardware by clicking hardware setup. You must connect your FPGA and install the

driver named USB master blaster

28) Select hardware device as USB master blaster 29) Now check the option Program/Configure and hit the start button

30) Congratulations! You have dumped you first program sr_latch. Now test it on hardware

Dumping a Program by Active Serial (AS) mode:


31) Click on the tab Assignments>Devices, then click on Device and Pin Option and go to in Configuration tab then set the EPCS16 as Configuration Devices from a drop down list now click OK and upon returning to your main schematic page Recompile it


32) Now follow the previous procedure as followed for JTAG mode. 33) Set the programming mode in programmer dialog box as Active Serial Programming, 34) A warning message in a pop-up window will appear, Click on Yes.


35) If there is no any Configuration file shown in the window so click on the Add File and then add

your file having a .pof extension (Programmer Object File)

36) Now slide the RUN/PROG button on the board to the PROG position. 37) Then place a check in the box in a column of Program/Configuration and finally click on the

START button.


38) Congratulations! You have successfully dumped your program in your board’s flash memory.

Using VerilogHDL for Programming: Now once you have implemented your design of S-R Latch we are glad to take you further towards the first example code of VerilogHDL. Here we would not explain you about the constructs of the Verilog, but there is plenty of literature available for this. We would recommend the book VerilogHDL by Samir Palnithkar for learning Verilog. As a beginner you must implement the following steps to get the idea that how programming is done in Verilog: 39) Now follow the previous steps for making a new project file under name of sr_latch.


40) Press file and select NEW. This will open a window. This time Choose “Verilog HDL file” under the device design files tab and click OK (refer to the figure of step 11).

41) Now copy-paste the following code in the main body. module sr_latch(q,qbar,s,r); output q,qbar; input s,r; nand g1(q,s,qbar); nand g2(qbar,r,q); endmodule

42) Now follow the same procedure from step #16 for pin assignment and dumping of program.


Author:

Shehzad Saleem El-023 (Batch 2008-09).

Edited & Compiled by: Syed Shahbaz Ali El-043 (Batch 2008-09).

Co-workers:

Adeel Amin El-015 (Batch 2008-09). Ahsan Saeed El-054 (Batch 2008-09).

fpga guide for beginners

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