The document provides a history of digital logic and programmable logic devices such as PLDs, CPLDs, and ASICs. It describes the advantages of FPGAs over other technologies including lower costs, faster time to market, and easier design changes. The architecture of FPGAs is explained including logic blocks, interconnects, embedded memory and DSP blocks. Modern SoC FPGAs integrate an ARM processor for improved performance. Applications include automotive, wireless, military, and medical imaging systems.

1. SoC FPGA TECHNOLOGY

2. HISTORY
• Digital Logic: (1950s-1960s)
3-input
Function
A
B
C
A B C Y
0 0 1 1
0 1 0 1
1 1 0 0
0 0 0 1
1 1 1 0
CMOS NAND Gate
Black Box Truth Table Digital Circuit
Sum of Products
Product of Sums

3. HISTORY
• Regular structures for two-level logic: (1960s-70s)
• Consist of MUXs, De-MUXs, Decoders, FFs.
• Yield spaghetti-like maze!
• Each modification means a new PCB.
• Engineers got fed up!

4. HISTORY
• Programmable Logic Devices (PLDs): (1970s-80s)
• Chip makers addressed this problem by unconnected arrays of AND-OR
gates.
• Fuses used to connect gates.
• Each fuse could be blown open or left close.
• Programming took place at manufacturers plants.
• Simple PLDs (SPLD) could only handle up to 10–20 logic equations.
• You had to break the design apart.
• Wiring was also required and it was a big no-no!
• Again engineers got fed up!

5. HISTORY
• Programmable Logic Devices (PLDs): (1970s-80s)
Programmed State

6. HISTORY
• Complex PLD (CPLD): (1980s)
• Contains a bunch of PLD blocks connected together
by a global interconnect matrix.
• Each component is programmed individually.

7. HISTORY
• Application Specific Integrated Circuits (ASICs):
• Not available circa 1980s!
• Custom fabricated design from scratch.
• Large complex functions, millions
of gates customised for extreme
speed and low power.
• Very expensive in small
quantities > $1 Million
• Very hard to design.
• NOT reprogrammable which means
high risks!

8. HISTORY
• Application Specific Integrated Circuits (ASICs):
• Any mistake means millions of dollars!
• June 1994, a flaw in Intel Pentium chip
causes a division error, discovered by
someone called Dr Nicely.
• December 20th 1994, Intel apologized
and replaced all flawed Pentiums upon request.
• Intel reserved $420 million to cover costs!
• Full story:
http://www.emery.com/1e/pentium.htm

9. PROBLEM
PLDs
•Limited
Complexity
•Thousands of
gates
•Easy to design
•Programmable
ASICs
•Large Complex
Functions
•Millions of gates
•Hard to design
•Not
reprogrammable
FPGA

10. FPGA DEFINITIONS
• Field Programmable Gate Arrays (FPGAs) are digital integrated
circuits (ICs) that contain configurable (programmable) blocks
of logic along with configurable interconnects between these
blocks.
• The “field programmable” portion of the FPGA’s name refers to
the fact that its programming takes place “in the field”.

11. WHY USE FPGA?
• The cost of an FPGA design is much lower than that of an ASIC.
• Implementing design changes is much easier in FPGA.
• Time to market for FPGAs is much faster.
• FPGAs make many small, innovative design companies viable.
• In 2003: 1500 to 4000 ASIC design starts and 5000 ASSP
design starts, while around 450,000 FPGA design starts in the
same year.

12. WHY USE FPGA?
• What distinguishes an FPGA from an ASIC is embodied in the
name:
Field P r o g r a m m a b l e Gate Array

13. FPGA ARCHITECTURE
• Programmable logic blocks called
Logic Elements (LEs).
1000+ → 100,000+
• Massive fabric of programmable
interconnects.
• LEs described as islands in a “sea”
of interconnects.
• Manufacturers refer to LE in different ways.
Altera refers to it as Adaptive Logic Module (ALM).
Xilinx refers to it as Configurable Logic Block (CLB).

14. ARCHITECTURE: LOGIC ELEMENTS
• 8-input divisible look-up table
(LUT).
• Four dedicated registers to improve
timing closure.
• Full Adders and MUXs.
• 25% of ALMs can be used as
distributed memory using MLABs. ALM for Altera Cyclone V

15. ARCHITECTURE: LUT
• LUT contains memory cells
to implement small
logic functions.
• Each cell holds ‘0’ or ‘1’.
• Programmed with outputs
of truth tables.
• Inputs select content of one
of the cells as output.

16. ARCHITECTURE: LAB AND ALM
• LABs are Logic Array Blocks
• Some FPGAs have two ALMs in each
LAB, while others have four.
• Fast programmable interconnect
within the LAB.
• This is complemented by an
equivalent hierarchy in the
interconnect.
LAB
ALM ALM
Logic Cell
Logic Cell
Logic Cell
Logic Cell
ALM ALM
Logic Cell
Logic Cell
Logic Cell
Logic Cell
LABs
ALMs
Logic Cells
Interconnect Speed

17. ALM connection
details for
Cyclone V

18. ARCHITECTURE: EMBEDDED MULTIPLIERS,
ADDERS, ETC.
• Some functions may be slow in
programmable logic.
• One common operation in DSP
applications,
Multiply-and-Accumulate (MAC).
• Some FPGAs provide entire MACs
as embedded functions.

19. ARCHITECTURE: MORE FEATURES
• Memory
• DSP Blocks
• PLLs
• Transceivers
• GPIO
• Hard IP
• That’s what
differentiates FPGA
from CPLD.

20. DESIGNING WITH FPGA: HDL
• Can’t design FPGA by hand; way too much logic to manage and hard to make changes.
• Hardware Descriptions Languages (HDL) are used to specify functionality of logic at a high
level.
• Most two popular languages are Verilog and VHDL (VHSIC Hardware Description Language).
D Q
Q
Verilog VHDL DFF

21. DESIGNING WITH FPGA: FLOW
• Validation:
• High level simulation to catch specification errors.
• Verify pin-outs and connections to other system
components.
• RTL Synthesis:
• Process of compiling HDL code into logic gates
and flip-flops.
• Technology Mapping:
• Map the logic onto elements available in the implementations
technology (LUTs).
• Placement and Routing:
• Assign logic blocks to functions.
• Make wiring connections.
Design System
Validation
RTL Synthesis
Place and Rout
Verification

22. DESIGNING WITH FPGA: FLOW
• Timing Analysis:
• Verify paths and determine delays.
• Check critical paths and improve their timing.
• Adjust placement of cells to improve timing closure.
• If the design does not fit it can be divided into multiple chips.
• Generate programming files which contain bits to be loaded in
the device.

23. DESIGNING WITH FPGA: OPENCL
• What is OpenCL (Open Computing Language)?
• Open standard framework that enables developers to write programs that execute
across heterogeneous systems including CPUs, GPUs, DSPs, and FPGAs.
• Benefits of OpenCL for FPGAs:
• Faster time-to-market: using the OpenCL C-based parallel
programming language as opposed to low-level HDL.
• Quick design exploration: by working at higher
level of abstraction.
• Easy design re-use: by retargeting existing OpenCL
code to current and future FPGAs.
• Faster design completion: by generating an FPGA
implementation in single step.

24. CONFIGURING FPGA
• Millions of SRAM cells hold LUTs and interconnect values.
• Volatile memory, loses configuration when power is turned off.
• Non-volatile memories are used to power up FPGAs with
specific bit file.

25. SoC FPGA
• Formerly, designers used to implement what so called soft
processors, which are microprocessors implemented in HDL.
• Popular IPs: NIOS II from Altera and MicroBlaze from Xilinx.
• Such architectures did not realize high performances, in
addition to resources consumption and power consumption.
• They were also vendor-specific.

26. SoC FPGA
• Chip makers again for the rescue!
• SoC FPGAs integrate an ARM-based hard
processor system (HPS) consisting of
processor, peripherals, and memory
interfaces with the FPGA fabric using
a high bandwidth interconnect backbone.
• It combines the performance and power
savings of hard intellectual property (IP)
with the flexibility of programmable logic.

27. SoC FPGA: ADVANTAGES
• Improved system performance: through a higher HPS to FPGA bandwidth
interconnect, hardware acceleration, and increased memory performance.
• Increased reliability: through error correction code (ECC) and memory
protection. Warm/Cold CPU reset that initiates without affecting or
reprogramming FPGA.
• More flexibility: through hardware differentiation, system boot and
configurations options, and multiple hardened memory controllers.
• Lower system cost: through single-chip integration, integrated PCIe
controller and no power off sequencing.

28. SoC FPGA
• FPGA Vendors and Processors:
FPGA Vendor Hard Processor Soft Processor
Actel None Third-Party only
Altera ARM NIOS, NIOS II
Lattice None Third-Party only
Xilinx IBM PowerPC MicroBlaze, PicoBlaze
QuickLogic MIPS Third-Party only

29. SoC FPGA: HPS
Cyclone V SoC HPS Architecture

30. SoC FPGA: HPS FEATURES
• 925 MHz, dual-core ARM® Cortex™-A9 MPCore™ processor.
• Each processor core includes:
• 32 KB of L1 instruction cache, 32 KB of L1 data cache.
• Single- and double-precision floating-point unit and NEONTM media
engine.
• CoreSightTM debug and trace technology.
• 512 KB of shared L2 cache.
• 64 KB of scratch RAM.
• Multiport SDRAM controller with support for DDR2, DDR3, and
LPDDR2 and optional error correction code (ECC) support.

31. SoC FPGA: APPLICATIONS
• Just to name a few:
• Automotive Advanced Driver Assistance Systems (ADAS)
• Wireless Communications
• Military Radar
• Military Secure Communications
• The top four manufacturers of electronic imaging systems all use FPGAs
• This include CT, MRI, and Ultrasonic equipment

32. DEMONSTRATIONS
• Morse Transmitter
• 9-bit Microprocessor (Hello World)
• SoC HPS Apps (G-Sensor)
• DE1-SoC Ubuntu Desktop

33. REFERENCES
• www.altera.com
• www.Xilinx.com
• www.fpga4fun.com
• FPGAs Instant Access by Clive “Max” Maxfield
• Rapid Prototyping of Digital Systems, SOPC Edition by James O.
Hamblen

34. QUESTIONS
Thanks for your listening!
For more information and questions: sirajmuhammad@outlook.com