Introduction to programmable logic.pdf

FYS4220/9220

Introduction to FPGA technology and programmable logic Lecture #1

Reading: chapter 1 in Zwolinski

J. K. Bekkeng, 3.7.2011

Lecturer Jan Kenneth Bekkeng (Senior Scientist FFI, Ass. prof-II Sounding rockets UIO) Email: – j.k.bekkeng[at]fys.uio.no

T&E

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Goals Learn digital design using programmable logic circuits (FPGA and CPLD) – Circuits – Design tools – Design methods

Learn VHDL to program hardware (FPGAs and CPLDs) for use in e.g. embedded systems

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Curriculum (VHDL & FPGA part) Lectures (and other handout material) Laboratory exercises Textbook: – Digital System Design with VHDL, 2nd Edition (by Mark Zwolinski)

The textbook readings complement the lectures!

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Laboratory exercises Lab 1: – Switches, LEDs, counters, debouncer, testbenches

Lab 2: – Use of components and packages, LPMs, FSM (vending machine)

Lab 3: – Control of ADC (state machine), timing

Lab 4: Mandatory for PhD students only – NIOS II processor in FPGA (other projects may be possible) Altera Laboratory Exercises Plasma and Space Physics

Laboratory exercises Room V442, Physics building Teaching assistant available from 10.15 to 14.00 for guidance on the lab days Lab availability (without guidance): – The lab at V442 is available Monday - Friday

Read the lab text and the corresponding manuals, and try to find solutions before you come to the lab. All mandatory labs (3 labs for FYS4220, 4 labs for FYS9220) must be approved in order to take the exam – All labs must be approved before 1. December Note that Quartus II Web Edition and Modelsim-Altera Starter Edition software can be downloaded for free from the Altera web page: Altera Free software Plasma and Space Physics

Other Recommended books for VHDL The Designer's Guide to VHDL, Volume 3, Third Edition (by Peter J. Ashenden)

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What is an embedded system? “An embedded system is designed to perform one or a few dedicated functions . Often has real-time computing constraints. By contrast, a general-purpose computer, such as a personal computer (PC), is designed to be flexible and to meet a wide range of end-user needs. Embedded systems are controlled by one or more main processing cores that are typically either microcontrollers, digital signal processors (DSP) or FPGAs Plasma and Space Physics

Examples of ”embedded systems” MP3 player Digital camera Washing machine GPS mottaker Blu-ray / DVD player

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Examples of FPGA use Pico satellite (OBC)

Aerospace Defence Medicine Imaging / Image processing Digital signal processing ASIC prototyping Software defined Radio Software defined GPS NSM Air-to-Air missile

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What is an FPGA? FPGA = Field Programmable Gate Array Logic Array Blocks (LABs) – Each LAB contains a given number of Logic Elements (LE)

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Cyclone II LE

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Cyclone II Family Summary

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Altera circuit families

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FPGA advantages High reliability High determinism High performance True parallelism Reconfigurability

DAQ = Data Acquisition

FPGAs in DAQ-systems (”intelligent DAQ”) DAQ-cards with a programmable FPGA Multi-rate sampling User defined processing in the FPGA FPGA based hardware timing/synchronization Plasma and Space Physics

NI R-series FPGA DAQ

Examples on use of FPGAs High-speed control Intelligent DAQ Digital communication protocols Sensor simulation Onboard processing and data reduction Co-processing Hardware In the Loop (HIL)-testing

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Why use FPGA in an embedded system?

Develop a low cost DSP system Scalability System integration (system on chip) True parallelism Many I/O (Input/Output) lines Note: All Altera IP’s can be used free of charge for universities!

DSP = Digital Signal Processor Plasma and Space Physics

System Integration – System On a Chip (SOC) Replace several DSP’s with a single chip Integrate several different system components on a single chip A circuit design demanding e.g.10 FPGAs a few years ago can no fit into a single FPGA FPGA Custom Interface Logic

General Purpose Processor

SOPC DSP Processor

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Custom Interface Logic

Spare gates

DSP Logic

Nios Processor

Ex: Inertial Reference Unit (IRU) Roll Roll (X)

Pitch (Y)

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Yaw (Z)

IRU PCBs

Roll PCB

Pitch /Yaw PCB

FPGA

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DAQ PCB

Power & I/O PCB

Development kit used in the lab

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Programmable logic FPGA CPLD CPLD

Flash

Circuit manufacturers: – Altera (www.altera.com) – Xilinx (www.xilinx.com)

Tools: – – – – –

QUARTUS II (Altera) Modelsim Altera (Mentor VHDL simulator) NIOS II Embedded design suite (+ C2H compiler) DSP builder (Altera) ISE (Xilinx)

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FPGA

Design using FPGA/CPLD

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Examples of programming languages for programmable logic VHDL SystemC Handel-C Verilog (mainly used for ASICs, VHDL is better for FPGAs) Schematic tools (e.g. in Quartus II)

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Altera System-Level Design Tools SOPC = System-On-a-Programmable-Chip

System Integration

IP Integration

DSP Algorithm Development Software Development 27 and Space Physics Plasma

Altera DSP Builder Interface between Quartus II (Altera) and MATLAB/Simulink (Mathworks) Library Add On to Simulink Automatic Generation of VHDL design From a MATLAB/Simulink Representation Creates HDL Code

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Automatic code generation

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Automatic code generation

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LabVIEW FPGA LabVIEW from National Instrument (NI) can be used to program (graphically) NI’s RIO (RIO = Reconfigurable I/O) cards Requires license on NI LabVIEW and NI FPGA Module Can write/import VHDL code

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Circuit technologies Programmable logic device (PLD): Simple Programmable Logic Device (SPLD) Complex Programmable Logic Devices (CPLD) Field Programmable Gate Array (FPGA) Application Specific Integrated Circuit (ASICs) System On Chip (SoC)

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When to use FPGAs / CPLDs Usually the first choice for digital logic, except for: – Very simple designs – Large production volumes (ASIC better) – Very complex designs • e.g. mixed signal (analog and digital on the same chip) • Very high speed or need for very low power consumption

Can replace microcontrollers in designs with: – – – –

A demand for many I/O lines Need for flexible I/O Requirements for parallel processing /fast processing High requirements on timing/triggering

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The difference between a processor and programmable logic A processor is programmed with instructions A programmable logic circuit is programmed with a circuit description A programmable logic circuit contains configurable blocks with logics and configurable connection lines between these blocks

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Programmable logic

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CPLD - Complex Programmable Logic Device Programming technology: non-volatile memory, such as EEPROM or FLASH. – Configuration stored in the circuit (even without power) – High voltage (EEPROM) or logic voltage (FLASH)

Used in ”small and medium size” designs

Circuit family example: MAX II from Altera – Up to 1270 LE

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FPGA - Field Programmable Gate Array Typically contains more logic then a CPLD Have many flip-flops (memory elements) Circuit examples: – Virtex-series (Xilinx) – Cyclone and Stratix-series (Altera) – Stratix V: 28 nm technologi, > 106 LE

FPGA

Flash

Programming technology: usually static memory (SRAM) – Needs an external configuration circuit with a non-volatile memory (based on EEPROM/FLASH) which loads the configuration into the FPGA at power on. – SRAM memory inside the FPGA stores the circuit configuration (when the power is on). Plasma and Space Physics

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Additional support in modern FPGAs On-chip memory, e.g. RAM blocks – dual port RAM -> can read and write the RAM in the same clock cycle

Processor cores (floating point operations possible) DSP blocks (floating point operations possible) Multiplier blocks High speed input/output blocks PLL (Phase locked loop) DLL (Delay locked loop) Intellectual Property (IP) – E.g. FFT, UART Plasma and Space Physics

FPGA vs ASIC ASIC = Application Specific Integrated Circuit – circuits that are fabricated in a silicon foundry

FPGA advantages – Dramatically reduce the cost of errors (by reprogramming) – Much cheaper than an ASIC for small volumes

FPGA disadvantages (compared to ASICs) – Lower performance (due to overhead of programmability) – Higher power consumption – Same logic requires a lager chip area

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Fast calculations – DSP blocks

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Reduction of power consumption

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Reduction of power consumption

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Processor cores in FPGA Processor cores inside the FPGA Many designs need a processor, and it is possible to avoid an external processor chip Soft core CPU – Programmable logic in the FPGA is used to implement a processor (when needed) together with other functionality

Hard core CPU – The processor is implemented in the FPGA at the production of the circuit

Xilinx processor cores for FPGA – Power PC (hard core processor) – MicroBlaze (soft core processor)

Altera processor core for FPGA – NIOS II (soft core processor) Plasma and Space Physics

Soft core processor Pros: – Include the processor core only when. – The number of cores is flexible. – Can reuse the design in newer generations of FPGAs in the future.

Cons: – Slower and simpler than hard processor cores. – Less area efficient compared to hard cores. Plasma and Space Physics

Hardware vs Software Hardware (digital logic): – Time critical parts Software (on the CPU): – Less time critical parts. – Interface (Ethernet, RS232, USB, Wi-Fi, etc.) – Code that normally would have been executed on an external processor.

Nios II C-to-Hardware Acceleration Compiler (C2H) – “boosts the performance of your time-critical ANSI C functions by converting them into hardware accelerators in the FPGA”. – “tool for software engineers who need to increase the performance of their embedded software applications.” Plasma and Space Physics

Intellectual Properties - IPs With today's large FPGA designs it is almost impossible to design everything from scratch. Solution: Use already developed blocks for the parts of the design where these are available. They are called Intellectual Properties (IP). IP types: – made internally – available from an FPGA manufacturer – available from a third part supplier

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Altera Embedded processing http://www.altera.com/technology/embedded/embindex.html

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Embedded development tools

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Some supported I/O standards

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How to simulate VHDL code Testbench(stimuli/test input is made using VHDL code) Waveforms (make a waveform input stimuli ”graphically”)

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Examples of COTS hardware for embedded systems National Instruments PXI rack with FPGA-card(s) and a real-time controller 18-slot PXI Express chassis

Controller with Windows and/or RT-OS

CompactRIO from NI

NI R-series FPGA DAQ

Real-time processor and FPGA

BeMicro (from Altera) – – –

Low cost ($49) Altera CycloneIII FPGA Altera NiosII embedded processor

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COTS = commercial off-the-shelf