1. George Mason University ECE 448 – FPGA and ASIC Design with VHDL FPGA Devices & FPGA Design Flow ECE 448 Lecture 6

2. 2ECE 448 – FPGA and ASIC Design with VHDL Required reading (1) S. Brown and Z. Vranesic, Fundamentals of Digital Logic with VHDL Design Chapter 3.6.5 Field-Programmable Gate Arrays P. Chu, FPGA Prototyping by VHDL Examples Chapter 2.2, FPGA

3. 3ECE 448 – FPGA and ASIC Design with VHDL Required Reading (2) Xilinx, Inc. Spartan-3 FPGA Family Module 1: Introduction Features Architectural Overview Package Marking Module 2: CLB Overview

4. 4ECE 448 – FPGA and ASIC Design with VHDL designs must be sent for expensive and time consuming fabrication in semiconductor foundry bought off the shelf and reconfigured by designers themselves Two competing implementation approaches ASIC Application Specific Integrated Circuit FPGA Field Programmable Gate Array designed all the way from behavioral description to physical layout no physical layout design; design ends with a bitstream used to configure a device

5. 5ECE 448 – FPGA and ASIC Design with VHDL Block RAMs Configurable Logic Blocks I/O Blocks What is an FPGA? Block RAMs

6. 6ECE 448 – FPGA and ASIC Design with VHDL Which Way to Go? Off-the-shelf Low development cost Short time to market Reconfigurability High performance ASICsFPGAs Low power Low cost in high volumes

7. 7ECE 448 – FPGA and ASIC Design with VHDL Other FPGA Advantages Manufacturing cycle for ASIC is very costly, lengthy and engages lots of manpower Mistakes not detected at design time have large impact on development time and cost FPGAs are perfect for rapid prototyping of digital circuits Easy upgrades like in case of software Unique applications reconfigurable computing

8. 8ECE 448 – FPGA and ASIC Design with VHDL Major FPGA Vendors SRAM-based FPGAs Xilinx, Inc. Altera Corp. Atmel Lattice Semiconductor Flash & antifuse FPGAs Actel Corp. Quick Logic Corp. Share about 90% of the market

9. 9ECE 448 – FPGA and ASIC Design with VHDL The Programmable Marketplace The Programmable Marketplace Q1 Calendar Year 2005 Source: Company reports Latest information available; computed on a 4-quarter rolling basis Xilinx Altera Lattice Actel QuickLogic: 2% Xilinx All Others Two dominant suppliers, indicating a maturing market PLD SegmentFPGA Sub-Segment Other: 2% 51% 33% 5% 7% Altera 58% 31% 11%

10. 10ECE 448 – FPGA and ASIC Design with VHDL Xilinx  Primary products: FPGAs and the associated CAD software  Main headquarters in San Jose, CA  Fabless* Semiconductor and Software Company  UMC (Taiwan) {*Xilinx acquired an equity stake in UMC in 1996}  Seiko Epson (Japan)  TSMC (Taiwan)  Samsung (Korea) Programmable Logic Devices ISE Alliance and Foundation Series Design Software

11. 11ECE 448 – FPGA and ASIC Design with VHDL Xilinx FPGA Families Old families XC3000, XC4000, XC5200 Old 0.5µm, 0.35µm and 0.25µm technology. Not recommended for modern designs. High-performance families Virtex (220 nm) Virtex-E, Virtex-EM (180 nm) Virtex-II (130 nm) Virtex-II PRO (130 nm) Virtex-4 (90 nm) Virtex-5 (65 nm) Virtex-6 (40 nm) coming in 2009 Low Cost Family Spartan/XL – derived from XC4000 Spartan-II – derived from Virtex Spartan-IIE – derived from Virtex-E Spartan-3 (90 nm) Spartan-3E (90 nm) – logic optimized Spartan-3A (90 nm) – I/O optimized Spartan-3AN (90 nm) – non-volatile, Spartan-3A DSP (90 nm) – DSP optimized Spartan-6 (45 nm) – coming in 2009

12. 12ECE 448 – FPGA and ASIC Design with VHDL

13. George Mason University ECE 448 – FPGA and ASIC Design with VHDL CLB Structure

14. 14ECE 448 – FPGA and ASIC Design with VHDL The Design Warrior’s Guide to FPGAs Devices, Tools, and Flows. ISBN 0750676043 Copyright © 2004 Mentor Graphics Corp. (www.mentor.com) General structure of an FPGA

15. 15ECE 448 – FPGA and ASIC Design with VHDL The Design Warrior’s Guide to FPGAs Devices, Tools, and Flows. ISBN 0750676043 Copyright © 2004 Mentor Graphics Corp. (www.mentor.com) Xilinx CLB

16. 16ECE 448 – FPGA and ASIC Design with VHDL CLB Structure

17. 17ECE 448 – FPGA and ASIC Design with VHDL The Design Warrior’s Guide to FPGAs Devices, Tools, and Flows. ISBN 0750676043 Copyright © 2004 Mentor Graphics Corp. (www.mentor.com) Xilinx CLB Slice

18. 18ECE 448 – FPGA and ASIC Design with VHDL CLB Slice Structure Each slice contains two sets of the following: Four-input LUT Any 4-input logic function, or 16-bit x 1 sync RAM (SLICEM only) or 16-bit shift register (SLICEM only) Carry & Control Fast arithmetic logic Multiplier logic Multiplexer logic Storage element Latch or flip-flop Set and reset True or inverted inputs Sync. or async. control

19. 19ECE 448 – FPGA and ASIC Design with VHDL LUT (Look-Up Table) Functionality Look-Up tables are primary elements for logic implementation Each LUT can implement any function of 4 inputs

20. 20ECE 448 – FPGA and ASIC Design with VHDL 5-Input Functions implemented using two LUTs One CLB Slice can implement any function of 5 inputs Logic function is partitioned between two LUTs F5 multiplexer selects LUT

21. 21ECE 448 – FPGA and ASIC Design with VHDL 5-Input Functions implemented using two LUTs LUT OUT

22. 22ECE 448 – FPGA and ASIC Design with VHDL The Design Warrior’s Guide to FPGAs Devices, Tools, and Flows. ISBN 0750676043 Copyright © 2004 Mentor Graphics Corp. (www.mentor.com) Xilinx Multipurpose LUT

23. 23ECE 448 – FPGA and ASIC Design with VHDL The Design Warrior’s Guide to FPGAs Devices, Tools, and Flows. ISBN 0750676043 Copyright © 2004 Mentor Graphics Corp. (www.mentor.com) Simplified view of a Xilinx Logic Cell

24. 24ECE 448 – FPGA and ASIC Design with VHDL RAM16X1S O D WE WCLK A0 A1 A2 A3 RAM32X1S O D WE WCLK A0 A1 A2 A3 A4 RAM16X2S O1 D0 WE WCLK A0 A1 A2 A3 D1 O0 = = LUT or LUT RAM16X1D SPO D WE WCLK A0 A1 A2 A3 DPRA0DPO DPRA1 DPRA2 DPRA3 or Distributed RAM CLB LUT configurable as Distributed RAM A single LUT equals 16x1 RAM Two LUTs Implement Single and Dual-Port RAMs Cascade LUTs to increase RAM size Synchronous write Synchronous/Asynchronous read Accompanying flip-flops used for synchronous read

25. 25ECE 448 – FPGA and ASIC Design with VHDL DQ CE DQ DQ DQ LUT IN CE CLK DEPTH[3:0] OUT LUT = Shift Register Each LUT can be configured as shift register Serial in, serial out Dynamically addressable delay up to 16 cycles For programmable pipeline Cascade for greater cycle delays Use CLB flip-flops to add depth

26. 26ECE 448 – FPGA and ASIC Design with VHDL Shift Register Register-rich FPGA Allows for addition of pipeline stages to increase throughput Data paths must be balanced to keep desired functionality 64 Operation A 4 Cycles8 Cycles Operation B 3 Cycles Operation C 64 12 Cycles 3 Cycles 9-Cycle imbalance

27. 27ECE 448 – FPGA and ASIC Design with VHDL COUT D Q CK S R EC D Q CK R EC O G4 G3 G2 G1 Look-Up Table Carry & Control Logic O YB Y F4 F3 F2 F1 XB X Look-Up Table F5IN BY SR S Carry & Control Logic CIN CLK CE SLICE Carry & Control Logic

28. 28ECE 448 – FPGA and ASIC Design with VHDL  Each CLB contains separate logic and routing for the fast generation of sum & carry signals Increases efficiency and performance of adders, subtractors, accumulators, comparators, and counters  Carry logic is independent of normal logic and routing resources Fast Carry Logic LSB MSB Carry Logic Routing

29. 29ECE 448 – FPGA and ASIC Design with VHDL Accessing Carry Logic  All major synthesis tools can infer carry logic for arithmetic functions Addition (SUM <= A + B) Subtraction (DIFF <= A - B) Comparators (if A < B then…) Counters (count <= count +1)

30. George Mason University ECE 448 – FPGA and ASIC Design with VHDL Input/Output Blocks (IOBs)

31. 31ECE 448 – FPGA and ASIC Design with VHDL Basic I/O Block Structure D EC Q SR D EC Q SR D EC Q SR Three-State Control Output Path Input Path Three-State Output Clock Set/Reset Direct Input Registered Input FF Enable

32. 32ECE 448 – FPGA and ASIC Design with VHDL IOB Functionality IOB provides interface between the package pins and CLBs Each IOB can work as uni- or bi-directional I/O Outputs can be forced into High Impedance Inputs and outputs can be registered advised for high-performance I/O Inputs can be delayed

33. George Mason University ECE 448 – FPGA and ASIC Design with VHDL Other Components of Spartan 3 FPGAs

34. 34ECE 448 – FPGA and ASIC Design with VHDL RAM Blocks and Multipliers in Xilinx FPGAs The Design Warrior’s Guide to FPGAs Devices, Tools, and Flows. ISBN 0750676043 Copyright © 2004 Mentor Graphics Corp. (www.mentor.com)

35. 35ECE 448 – FPGA and ASIC Design with VHDL A simple clock tree The Design Warrior’s Guide to FPGAs Devices, Tools, and Flows. ISBN 0750676043 Copyright © 2004 Mentor Graphics Corp. (www.mentor.com)

36. 36ECE 448 – FPGA and ASIC Design with VHDL The Design Warrior’s Guide to FPGAs Devices, Tools, and Flows. ISBN 0750676043 Copyright © 2004 Mentor Graphics Corp. (www.mentor.com) Digital Clock Manager (DCM)

37. George Mason University ECE 448 – FPGA and ASIC Design with VHDL Spartan-3 Family Attributes

38. 38ECE 448 – FPGA and ASIC Design with VHDL Spartan-3 FPGA Family Members

39. 39ECE 448 – FPGA and ASIC Design with VHDL FPGA Nomenclature

40. 40ECE 448 – FPGA and ASIC Design with VHDL FPGA device present on the RC10 board XC3S1500-4FG320 Spartan 3 family 1500 k = 1.5 M equivalent logic gates speed grade -4 = standard performance 320 pins package type

41. George Mason University ECE 448 – FPGA and ASIC Design with VHDL Celoxica RC10 FPGA Board

42. 42ECE 448 – FPGA and ASIC Design with VHDL

43. 43ECE 448 – FPGA and ASIC Design with VHDL

44. 44ECE 448 – FPGA and ASIC Design with VHDL

45. George Mason University ECE 448 – FPGA and ASIC Design with VHDL FPGA Design Flow

46. 46ECE 448 – FPGA and ASIC Design with VHDL Design flow (1) Design and implement a simple unit permitting to speed up encryption with RC5-similar cipher with fixed key set on 8031 microcontroller. Unlike in the experiment 5, this time your unit has to be able to perform an encryption algorithm by itself, executing 32 rounds….. Library IEEE; use ieee.std_logic_1164.all; use ieee.std_logic_unsigned.all; entity RC5_core is port( clock, reset, encr_decr: in std_logic; data_input: in std_logic_vector(31 downto 0); data_output: out std_logic_vector(31 downto 0); out_full: in std_logic; key_input: in std_logic_vector(31 downto 0); key_read: out std_logic; ); end AES_core; Specification (Lab Experiments) VHDL description (Your Source Files) Functional simulation Post-synthesis simulation Synthesis

47. 47ECE 448 – FPGA and ASIC Design with VHDL Design flow (2) Implementation Configuration Timing simulation On chip testing

48. 48 Tools used in FPGA Design Flow Synplicity Synplify Pro Synplicity Synplify Pro Design Synthesis Implementation Xilinx ISE VHDL code Netlist Bitstream Xilinx XST Functionally verified VHDL code

49. George Mason University ECE 448 – FPGA and ASIC Design with VHDL Synthesis

50. 50ECE 448 – FPGA and ASIC Design with VHDL Synthesis Tools … and others Synplify Pro Xilinx XST

51. 51ECE 448 – FPGA and ASIC Design with VHDL architecture MLU_DATAFLOW of MLU is signal A1:STD_LOGIC; signal B1:STD_LOGIC; signal Y1:STD_LOGIC; signal MUX_0, MUX_1, MUX_2, MUX_3: STD_LOGIC; begin A1<=A when (NEG_A='0') else not A; B1<=B when (NEG_B='0') else not B; Y<=Y1 when (NEG_Y='0') else not Y1; MUX_0<=A1 and B1; MUX_1<=A1 or B1; MUX_2<=A1 xor B1; MUX_3<=A1 xnor B1; with (L1 & L0) select Y1<=MUX_0 when "00", MUX_1 when "01", MUX_2 when "10", MUX_3 when others; end MLU_DATAFLOW; VHDL description Circuit netlist Logic Synthesis

52. 52ECE 448 – FPGA and ASIC Design with VHDL Circuit netlist (RTL view)

53. 53ECE 448 – FPGA and ASIC Design with VHDL Mapping LUT2 LUT3 LUT4 LUT5 LUT1 FF1 FF2 LUT0

54. RTL view in Synplify Pro incrementercomparator General logic structures can be recognized in RTL view MUX

55. Crossprobing between RTL view and code Each port, net or block can be chosen by mouse click from the browser or directly from the RTL View By double-clicking on the element its source code can be seen: Reverse crossprobing is also possible: if section of code is marked, appropriate element of RTL View is marked too:

56. Technology View in Synplify Pro Technology view is a mapped RTL view. It can be seen by pressing button or by double-click on “.srm” file As in case of “RTL View”, buttons can be used here Two additional buttons are enabled: - show critical path - open timing analyst - open timing analyst Technology view is presented using device primitives Ports, nets and blocks browser Pay attention: technology view is usually large and presented on number of sheets

57. Viewing critical path Critical path can be viewed by pressing on Delay values are written near each component of the path

58. Timing Analyst Timing analyst opened by pressing on Timing analyst gives a possibility to analyze different paths in the design Timing analyst can be opened only from Technology View

59. George Mason University ECE 448 – FPGA and ASIC Design with VHDL Implementation

60. 60ECE 448 – FPGA and ASIC Design with VHDL Implementation After synthesis the entire implementation process is performed by FPGA vendor tools

61. 61ECE 448 – FPGA and ASIC Design with VHDL

62. 62ECE 448 – FPGA and ASIC Design with VHDL Translation UCF NGD EDIF NCF Native Generic Database file Constraint Editor or Text Editor User Constraint File Native Constraint File Electronic Design Interchange Format Circuit netlistTiming Constraints Synthesis

63. 63ECE 448 – FPGA and ASIC Design with VHDL Pin Assignment LAB2 CLOCK CONTROL(0) CONTROL(2) CONTROL(1) RESET SEGMENTS(0) SEGMENTS(1) SEGMENTS(2) SEGMENTS(3) SEGMENTS(4) SEGMENTS(5) SEGMENTS(6) H3 K2 G5 K3 H1 K4 G4 H5 H6 H2 P10 B10 FPGA

64. 64ECE 448 – FPGA and ASIC Design with VHDL

65. 65ECE 448 – FPGA and ASIC Design with VHDL Mapping LUT2 LUT3 LUT4 LUT5 LUT1 FF1 FF2 LUT0

66. 66ECE 448 – FPGA and ASIC Design with VHDL Placing CLB SLICES FPGA

67. 67ECE 448 – FPGA and ASIC Design with VHDL Routing Programmable Connections FPGA

68. 68ECE 448 – FPGA and ASIC Design with VHDL Configuration Once a design is implemented, you must create a file that the FPGA can understand This file is called a bit stream: a BIT file (.bit extension) The BIT file can be downloaded directly to the FPGA, or can be converted into a PROM file which stores the programming information

69. Two main stages of the FPGA Design Flow Synthesis Technologyindependent Technologydependent Implementation RTL Synthesis Map Place & Route Place & Route Configure - Code analysis - Derivation of main logic constructions - Technology independent optimization - Creation of “RTL View” - Mapping of extracted logic structures to device primitives - Technology dependent optimization - Application of “synthesis constraints” -Netlist generation - Creation of “Technology View” - Placement of generated netlist onto the device -Choosing best interconnect structure for the placed design -Application of “physical constraints” - Bitstream generation - Burning device

70. 70ECE 448 – FPGA and ASIC Design with VHDL Report files

71. 71ECE 448 – FPGA and ASIC Design with VHDL Map report header Release 8.1i Map I.24 Xilinx Mapping Report File for Design 'Lab3Demo' Design Information ------------------ Command Line : c:\Xilinx\bin\nt\map.exe -p 3S1500FG320-4 -o map.ncd -pr b -k 4 -cm area -c 100 Lab3Demo.ngd Lab3Demo.pcf Target Device : xc3s1500 Target Package : fg320 Target Speed : -4 Mapper Version : spartan3 -- $Revision: 1.34 $ Mapped Date : Tue Feb 13 17:04:54 2007

72. 72ECE 448 – FPGA and ASIC Design with VHDL Map report Design Summary -------------- Number of errors: 0 Number of warnings: 0 Logic Utilization: Number of Slice Flip Flops: 30 out of 26,624 1% Number of 4 input LUTs: 38 out of 26,624 1% Logic Distribution: Number of occupied Slices: 33 out of 13,312 1% Number of Slices containing only related logic: 33 out of 33 100% Number of Slices containing unrelated logic: 0 out of 33 0% *See NOTES below for an explanation of the effects of unrelated logic Total Number 4 input LUTs: 62 out of 26,624 1% Number used as logic: 38 Number used as a route-thru: 24 Number of bonded IOBs: 10 out of 221 4% IOB Flip Flops: 7 Number of GCLKs: 1 out of 8 12%

73. 73ECE 448 – FPGA and ASIC Design with VHDL Place & route report Asterisk (*) preceding a constraint indicates it was not met. This may be due to a setup or hold violation. ------------------------------------------------------------------------------------------------------ Constraint | Requested | Actual | Logic | Absolute |Number of | | | Levels | Slack |errors ------------------------------------------------------------------------------------------------------ * TS_CLOCK = PERIOD TIMEGRP "CLOCK" 5 ns | 5.000ns | 5.140ns | 4 | -0.140ns | 5 HIGH 50% | | | | | ------------------------------------------------------------------------------------------------------ TS_gen1Hz_Clock1Hz = PERIOD TIMEGRP "gen1 | 5.000ns | 4.137ns | 2 | 0.863ns | 0 "gen1Hz_Clock1Hz" 5 ns HIGH 50% | | | | | ------------------------------------------------------------------------------------------------------

74. 74ECE 448 – FPGA and ASIC Design with VHDL Post layout timing report Clock to Setup on destination clock CLOCK ---------------+---------+---------+---------+---------+ | Src:Rise| Src:Fall| Src:Rise| Src:Fall| Source Clock |Dest:Rise|Dest:Rise|Dest:Fall|Dest:Fall| ---------------+---------+---------+---------+---------+ CLOCK | 5.140| | | | ---------------+---------+---------+---------+---------+ Timing summary: --------------- Timing errors: 9 Score: 543 Constraints cover 574 paths, 0 nets, and 187 connections Design statistics: Minimum period: 5.140ns (Maximum frequency: 194.553MHz)