CS-280Dr. Mark L. Hornick

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Parts of a GP Computer (Microcomputer)

Contains separate•Microprocessor chip•Memory/Memory controller•MB control chips•Peripheral (I/O) devices(one chip for each function)

• serial comm• parallel comm• USB • Bluetooth• IR• AGP graphics• WiFi• CD/DVD interface• PCI expansion slots• …

CS-280Dr. Mark L. Hornick

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How does a Microcomputer differ from a Microcontroller?

CS-280Dr. Mark L. Hornick

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How does a Microcomputer differ from a Microcontroller?Microcontroller:

“1-chip” solution (monolithic) Built-in components (depending on variant)

Microprocessor Memory: RAM/SRAM, EEPROM/EPROM/PROM/ROM Peripheral devices

serial/parallel ports digital I/O ports Analog/Digital converter Timer/Counter

Inside an IC package

CS-280Dr. Mark L. Hornick

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Inside an IC package

CS-280Dr. Mark L. Hornick

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CS-280Dr. Mark L. Hornick

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Atmel Atmega32 Central Processing Unit

Arithmetic Logic Unit (ALU) performs the actual arithmetic, logical, and bit-functions

Memory – SRAM, EEPROM, Flash, etc.

Clock circuit – internal/external I/O – Input/Output; video, serial,

parallel, USB, SCSI, etc.

CS-280Dr. Mark L. Hornick

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CS-280Dr. Mark L. Hornick

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Atmel Atmega32 highlightsAn 8-bit microcontroller featuring:

3 separate on-chip memories (Harvard architecture) 2KB SRAM (for data – volatile; data lost on power off) 1KB EEPROM (for persistent data storage – holds data after power off) 32KB Flash (organized as 16K of 16-bit words for persistent program code)

Native data size is 1 byte (SRAM and EEPROM)

16-bit data addressing Up to 64 KB (216 bytes) of data memory can be accessed

8-pin I/O ports named A, B, C, and D, configurable as: Digital input (for reading discrete external signals on each pin (0v or 5v) as data

values 0 or 1) Digital output (for writing binary data values as discrete output signals (0v or 5v) Analog input (for reading continuous external signals (0v-5v) as data values) Serial/Parallel (for reading or writing streams of bytes) Pulse accumulator (for counting #changes of external signals)

The Atmega32 design is based on a Harvard Architecture: Assigns data and program instructions

to different memory spaces. Program data occupies a different and

separate memory from the program itself.

Each memory space has a separate bus, allowing:1. Different timing, size, and structure for

program instructions and data

2. Concurrent access to data and instructions (increases speed)

3. Clear partitioning of data and instructions (better security)

Drawback: Harder to program

Microcontroller Components 9

Most general-purpose microprocessors (like in your PC) use a von Neumann Architecture

1. Data and instructions are both stored in the same main memory

2. The content of any part of memory is addressable by location without regard to what is stored in that location – program or data

3. Instructions are executed sequentially. In case of accidental or intentional programming errors, data can be executed – a common attack used by viruses

Main Memory

CPU

Data

+Program

10Microcontroller Components