Complex Electronic Hardware

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Complex Electronic Hardware

• Clive Lee

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Complex Electronic Hardware

• Range of Logic Devices
• Programmable Logic Devices (PLDs)
• Programmable Logic
• Field Programmable Gate Arrays
• Application Specific Integrated Circuits (ASICs)
• PLDs/ASICs

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Complex Electronic Hardware

• Hardware that is programmed like software
• Based on Integrated Circuits (ICs or chips)
• ICs connected on Circuit Board
• Circuit Board interfaced with other devices
  (sensors, actuators) to provide system function

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Complex Electronic Hardware

• Integrated Circuits becoming more complex
• Scale of Integration no of transistors
• VLSI very large (gt1 hundred thousand) c.1980
• ULSI ultra large (gt 1 million transistors)
  c.1990
• WSI wafer processor memory FAILED 1984
• SOC system on chip 1990s

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System on a Chip
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System on a Chip

• Typical system consists of
• 1 or more microprocessor core(s)
• General or specialised (e.g. microcontroller or
  DSP)
• Memory
• RAM (SRAM, Flash), ROM, EEPROM
• Timing sources oscillators, PLL
• External Interfaces
• USB, Ethernet, SPI, FireWire, UART, CAN
• Analog interfaces
• ADC, DAC, UART

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Complex Electronic Hardware

• Provides logic or function
• given inputs produce specified outputs
• Based on integrated circuits connected
• Chips with transistors, resistors, capacitors
  
• Used to be many SSI chips on Circuit Board
• Small scale integration (lt30 transistors on chip)
  
• Now fewer but higher density devices
• More than 1 million transistors on chip
• E.g. Itanium processor

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Logic on Integrated Circuit
TTL 7400 quad NAND gates
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Programmable Logic
A
B
Sum of Products e.g. _
_ ABAB
Programmed by blowing fuses to select AND inputs
(products)
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Programmable Logic Devices (1)

• SPLD Simple Programmable Logic Device
• PLA AND-plane and OR-plane
• PAL AND-plane and fixed OR-plane
• CPLD Complex Programmable Logic Device
• Multiple SPLD-like blocks on one chip
• FPGA Field Programmable Gate Array
• Logic blocks and interconnect resources

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Simple PLD Example

• 1983 AMD released 22V10 device
• 24 pins with 10 outputs
• Replaced all of AMD 24 pin fixed function ICs
• Configured during manufacture
• Programmable AND and fixed OR gates

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Programmable Logic Devices (2)

• FPGA Field Programmable Gate Array
• Logic blocks and interconnect resources
• Structured ASIC
• Upper layers of chip programmable
• Lower levels of chip standard logic facilities
• ASIC Application Specific Integrated Circuit
• All layers of chip specific to application
• MicroProcessor / System on Chip
• All layers on chip provide general purpose
  computing platform.

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Complex Electronic Hardware
Programmable Logic Devices
2 Major Categories
Application Specific Integrated Circuits
SPLD
Simple PLDs
CPLD
Complex
High CapacityPLDs
Structured ASIC
HCPLD
FPGA
Field Programmable Gate Arrays
Cell based ASIC
Custom ASIC
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Programmable Logic Devices
Programmable Logic Devices
SPLD
Simple PLDs
CPLD
Complex PLDs several PLDs connected together
High CapacityPLDs
HCPLD
FPGA
Field Programmable Gate Arrays
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Complex PLDs (CPLDs)

• Complexity lies between Simple PLDs and FPGAs
• Like PALs
• Based on sum-of-products logic array.
• Little scope for internal state or deeply layered
  logic
• Like FPGAs
• Equivalent to large no gates (up to 100,000, cf
  100 PAL)
• More complicated logic available than sum of
  products e.g. feedback, common functions such
  as integer arithmetic
• Non-volatile on chip memory
• Boot loader, can be used to load FPGA with
  configuration data

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Complex PLD Example

• Altera MAX 7000 family
• Equivalence 600 - 10,000 gates, 36 to 212 pins

• Altera, Atmel, Xilinx, Lattice Semiconductor

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FPGA Properties

• Up to several million gates
• High level embedded functions (adders,multipliers)
  
• Embedded memories
• Can be fully or partially reconfiguredFPGA
  Architecture
• Based on Configurable Logic Blocks
• LUT determines function of block
• Interconnections can be switched.

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FPGA Example

• Company - Family
• Xilinx Virtex, Spartan
• Altera Stratix, Cyclone, Flex
• Lattice Semiconductor
• Actel ProASICplus
• QuickLogic
• Actmel

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FPGA Modern Trends

• Additional functions (Hardware)
• FPGA chip has additional functions inbuilt on
  manufacture (e.g. microprocessor core, DAC, ADC,
  communications)
• Additional functions (Software)
• Extra functions inbuilt by committing gates to
  provide required logic (e.g. soft cores such as
  microprocessors and other IP code).

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Complex Electronic Hardware
Programmable Logic Devices
2 Major Categories
Application Specific Integrated Circuits
SPLD
Simple PLDs
CPLD
Complex
High CapacityPLDs
Structured ASIC
HCPLD
FPGA
Field Programmable Gate Arrays
Cell based ASIC
Custom ASIC
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ASICs
System-on-Chip
ASSP Application Specific Standard Product
Application Specific Integrated Circuit
Over 100 thousand gates
Structured ASIC
Predefined layers in chip
Cell based ASIC
Technology-library
Custom ASIC
Every function optimised
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ASIC Design Steps

• Description of ASIC in Hardware Design Language
  (HDL) e.g. VHDL, Verilog
• Translation into RTL (Register Transfer Level)
• Verification by simulation tool
• Translation by logic synthesis tool into
  gate-level netlist e.g. blocks, cells and
  connections
• Routing tool produces photomasks
• Estimates of power consumption,parasitic
  resistance, capacitance, delays made.

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Hardware Design Processes
System Safety Assessment Process
Hardware Life Cycle Processes
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Implementation Options

• Computing System Choice
• Microprocessor System
• General Purpose with logic interpreted
• ASIC System
• Application Specific with logic inbuilt
• FPGA System
• Logic selected or tailored

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Micro, ASIC, FPGA Comparison
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Complex Electronic Hardware Devices - Issues

• They cannot be tested for all inputs and paths
• They are developed by tools which may introduce
  additional errors
• They are more likely to have undetected design
  and implementation faults
• They have unanticipated interactions
• It is a common observation during development
  that the requirements are inadequate,
  particularly incomplete

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Acronyms Abbreviations
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Questions