CS-280 Dr. Mark L. Hornick 1 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-280 Dr. Mark L. Hornick 2 How does a Microcomputer differ from a Microcontroller?

CS-280 Dr. Mark L. Hornick 3 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-280 Dr. Mark L. Hornick 4

Inside an IC package CS-280 Dr. Mark L. Hornick 5

CS-280 Dr. Mark L. Hornick 6 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-280 Dr. Mark L. Hornick 7

CS-280 Dr. Mark L. Hornick 8 Atmel Atmega32 highlights An 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 (2 16 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 Components9

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