Microprocessors

1. Microprocessors Chapter 2

2. External Data Bus • Make sure that you read the analogy explaining exactly what the external data bus is • binary system - a numbering system using 0’s and 1’s only • Binary numbering will be in groups of 8 because 8 bits make a byte • How do you read bits, and change binary to decimals?

3. Binary System • Example: 10010101 • 1 : 1 • 2 : 2 • 3 : 4 • 4 : 8 • 5 : 16 • 6 : 32 • 7 : 64 • 8 : 128

4. Registers / Clocks • Registers • Used as a workplace for problems that you give the PC • Clocks • the maximum number of clock cycles that your CPU can handle is called the clock speed • a CPU’s clock speed is its maximum speed, not the speed that it will always run at • the system crystal determines the speed at which the CPU will operate

5. Clocks • The system crystal is a quartz oscillator that is soldered into the motherboard • A CPU can be pushed by a crystal with a lower clock speed that its own, but the CPU will operate at the speed of the crystal • Don’t try to run a CPU faster than its clock speed, or it will overheat and lock up • Underclocking - run a CPU slower that its CS • Overclocking - run a CPU faster than its CS

6. RAM as a spreadsheet • The CPU needs a place to store data, that’s where RAM comes into place • Quick Terminology Chart • Any individual 1 or 0 = a bit • 4 bits = a nibble • 8 bits = a byte • 16 bits = a word • 32 bits = a double word • 64 bits = a paragraph

7. MCC / Address Bus • Memory Controller Chip (MCC) • device that facilitates the flow of data from RAM to the CPU • Address Bus • second set of wires that enables the CPU to communicate with the MCC • MCC - grabs contents of RAM • Address Bus - controls what it gets

8. CPU packages • Dual Inline Pin Package (DIPP) • Pin Grid Array (PGA) (ZIF) • Staggered Pin Grid Array (SPGA) • Plastic/Ceramic Quad Flat Pack (PQFP) • Used on laptops • Plastic/Ceramic Leaderless Chip Carrier • Single Edge Contact Cartridge (SECC) • Plastic Pin Grid Array (PPGA)

9. Voltage Regulators • Can convert one voltage of electricity into a lower one • Are near a fan because they generate a good deal of heat • Thanks to laptops we use these in PCs • Necessary to reduce CPU to 3.3 v • Voltage set by jumper setting • APM also was developed around this time

10. Cache • Cache - set aside data used in the past in a special, fast storage area • enables you to speed up the system by creating special storage areas for data being moved form the hard rive, RAM, and CPU

11. Dynamic RAM (DRAM) • RAM of choice in the PC world • cheap, small, and relatively fast • Hold capacitors, like batteries, that hold small charges, need to be refreshed • considered volatile RAM • not as fast as the CPU

12. Static RAM (SRAM) • SRAM helps get rid of wait states • uses a special circuit called a flip-flop, which gets rid of refresh • almost as fast as the fastest CPU • very expensive, but doesn’t need to be refreshed, so uses less effort, PC more efficient

13. Internal/External Cache • Internal cache • small SRAM Cache built in to chip • called L1 cache • External cache • called L2 cache • soldered onto the motherboard in old PC’s • mostly integrated into chips since Pentium II

14. Clock doubling • Running the internals of a CPU at one clock speed, and running the external data bus and address bus at another slower, speed • to help CPU makers increase clock speeds without having to change the motherboards

15. Pentium • Intel introduced the Pentium processor in 1993 • had a 64-bit external data bus that split internally as 2 dual pipelined 32-bit data buses • dual pipelining - second set of circuitry that enables more than one command to be processed at a time

16. Pentium • The first 2 Pentium CPU’s, the 60 MHz and 66MHz, needed 5 volts for operation • ran very hot • Used clock doubling because motherboards that couldn’t keep up with speed • Jumper used to set multiplier

17. Pentium and competitors • The text discusses several different competitors as well as Pentium II & III. You should know why each one was introduced and different cache sizes, speeds, and clock doubling. Take time to read through these.

18. Celeron • Intel-based CPU • Low-end (cheap) • SEP (like SEC, but no plastic side) • Added 128K cache • Problems • SEC was proprietary • Only ran at 66Mhz, with multiplier • Celeron II • Same thing, only in PGA form

19. Duron • AMD’s answer to Celeron • 200 Mhz bus (2 X 100), faster than 66 Mhz • Cheap, therefore popular • PGA

20. Pentium II • SEC cartridge • Fit into “Slot 1” (Intel) • Used MMX technology • 57 new commands in instruction set • Four new registers • AMD countered with K6 • Could support 100 Mhz motherboards • Could not fit into Slot 1, so motherboards had to be created for it

21. Athlon • AMD’s answer to the Pentium II • Proprietary to AMD, SEC-type • Faster than Celeron (100 Mhz vs 66) • Could run 2 calculations per cycle, so effectively ran at 200-266 Mhz

22. Pentium III • Supports 100/133 Mhz motherboards • High-speed L2 cache • First came in SEC, then in PGA type • Less space, cheaper to make

23. Xeon • Intel-based CPU, slot 1 (SEC) • Even bigger caches

24. Pentium 4 • Takes 100 Mhz motherboard and allows four data transfers per cycle, total of 400 Mhz bus (double of Athlon)

25. Miscellaneous • Slockets • Adapters that allow you to place a PGA CPU in a Socket 1 slot • Overclocking • Author discourages it, although it may work • Intel doesn’t guarantee it above certain speeds • More worried about resellers than ultimate customers