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• iot

  Internet of Things
• Microcontroller


  A single chip, self-contained computer with a CPU, RAM, ROM, I/O, timer, interrupt circuitry, buses, oscillatory circuits, and A/D converters

  
• Microprocessor


  A general-purpose processor that requires external components to interact
• Microcontroller vs Microprocessor Differences

  • Cost: Cheap vs Expensive
  • Speed: Slow (in MHz Range) vs Fast (in GHz Range)
  • Purpose: Special vs General
  • Dependency: Single Chip has almost all components vs Need external components to be able to interact
  • Resources: Limited vs Unlimited

  
• Embedded Systems


  • Microcontroller-based systems designed for specific applications

  
• Major market players for microcontrollers


  • Texas Instruments
  • Atmel Corporation
  • Microchip
  • Renesas Technology Corp.
  • Intel Corporation
  • STMicroelectronics
  • Freescale Semiconductor
• AVR Microcontroller


  A family of microcontrollers developed by Atmel Corporation, an American-based designer and manufacturer of semiconductors

  
• AVR Microcontroller


  • Conceived by two students at the Norwegian Institute of Technology (Alf-Egil Bogen and Vegard Wollan)
  • AVR = Alf and Vegard's RISC processor
• AVR Microcontroller Families


  • Tiny AVR family (8-32 pin, 16 members)
  • Mega AVR family (32-100 pin, 23 members)
  • Xmega AVR family (32-100 pin)
  • AVR UC3 (32-bit, DSP support, dual port SRAM)
• ATmega16 Microcontroller


  • Harvard architecture
  • 8-bit microcontroller
  • High performance - 16MIPS @ 16MHz
  • EEPROM - non-volatile memory
  • Two 8-bit, One 16-bit timer with total 4 PWM channels
  • On-chip 10-bit ADC, 8 channels
  • UART, I2C, SPI protocol support

  
• Processor Core


  The main part of any microcontroller, often taken from an existing processor
• Memory


  Registers: Temporary (internal) storage elements

  Data/Instruction Memory: External memory to a CPU
• EEPROM


  Electrically Erasable and Programmable ROM
• Buses


  Data bus, address bus, and control bus connect the registers, ALU, and other components
• Port


  A group of 8 pins or a set of pins used for exchanging data with the external world
• Pull-up and Pull-down Resistors

  Used to ensure tri-stated input pins always read HIGH (1) when not driven by an external entity
• I/O Ports


  • Port A, Port B, Port C, Port D - General Purpose 8-bit bidirectional I/O ports with optional internal pull-up resistors
• DDRx (Data Direction Register)


  Configures the data direction of the port pins (input or output)
• PORTx (R/W)


  Used to write values to the port pins in output mode, and configure pull-up/tri-state in input mode
• PINx


  Used to read data from port pins when the port is configured as input