MICROCOMPUTER application introduction.ppt

MICROCOMPUTER application introduction.ppt

• 1.
  Microcomputer Systems • Outline –What is a Microcomputer? – Types of Microcomputers – Modular Microcomputer – Clock and CPU Control Circuits – Address Decoder – Address and Data Bus Buffers – Buffer Control – Bus Arbitration Control – Memory Management – Memory Module – Peripherals Module • Goal – Understand components of modular microcomputer • Reading – Microprocessor Systems Design, Clements, Ch. 1
• 2.
  Topics • Microcomputer systems •68k programmer model • 68k signal description • 68k memory hierarchy • 68k instruction set - briefly • 68k C and assembly code programming • Static RAM • Memory read and write cycles • Address decoding • Exceptions - interrupts, exceptions
• 3.
  Topics • I/O fundamentals •Parallel I/O & Timers • Serial I/O • Microcomputer buses • Dynamic RAM - organization and timing • Microcomputer systems design
• 4.
  Assignment (cont.) • Ifyou have PC with CD-ROM drive – get CDROM out of your book – try to install cross-assembler and C compiler on your PC – see if they will assemble and compile a simple program – you can then do coding at home and bring floppy to lab – note we will use GNU C compiler in class • Everyone – labs start second week – read lab assignment in advance – bring some PC floppies to lab – end of this week - check that your ID will access HRBB 217 – make sure you have Neo account for class email
• 5.
  What is aMicrocomputer? • Microcomputer (uC) = microprocessor-based computer • Microprocessor (uP) = single-chip or chipset CPU • Chipset - few closely-interacting chips – 68020 - integer+control, MMU, floating point – VAX 8200 - integer+control+MMU, microcode, floating point • All computers today have single-chip CPU – off-chip delays force all high-speed paths on chip – 2.26+ GHz P4 » off-chip path is 500 MHz » 2 levels of memory cache on chip – “chipset” is interface chip for CPU » memory interface, mouse, keyboard, graphics, USB, ...
• 6.
  Types of Microcomputers •Single board computer (SBC) – usually an embedded computer - buried inside a product • Features – dedicated to a single fixed task – minimum hardware to support the task » minimize cost, power, weight, size • Examples – PostScript printer, ATM, microwave oven, cell phone • Microcontroller – board shrunk to single chip - most common uC – CPU, memory, I/O – Examples: ARM, 68HC11, 8051
• 7.
  Types of Microcomputers •Modular microcomputer – modules connected by a bus – usually a general-purpose computer • Features – used for wide range of applications – flexible hardware to support application range » can mix and match modules as needed » example - add more memory modules • Examples – personal computer, factory controller
• 8.
  Modular Microcomputer • System= modules linked by system bus – system bus - data transfer between modules – local bus - data transfer within module • Advantages – standard modules assembled to form computer – large number of module types available – can easily customize computer to application needs • System bus standards – bus specification agreed upon by all manufacturers – often first a proprietary bus » Motorola Versabus => VME bus – now industry committees agree to bus standards
• 9.
  Figure 1.1 CPU ModuleMemory Module Peripherals Module System Bus Buffers Buffers Buffers CPU MMU Local Memory Clock Bus Arbitration DRAM DRAM Ctl Addr Decode Parallel I/O Serial I/O Timer Disk Cntlr USB Firewire ...
• 10.
  Clock and CPUControl • Time reference to CPU. – square or sine wave – 1000 MHz for 500 MHz Alpha • Also forms master clock used for rest of system – synchronize bus, other modules • Power-on reset – force CPU to initialize and execute start-up routine » bootstrap code – initiated when power first turned on » can also initiate manually - the reset button
• 11.
  Address Decoder • Divide upaddress space – allocate to individual memory units • Divide up among memory chips – e.g. split 64 MB across 32 16 Mb DRAM chips • Partition physical memory locations – local memory on CPU board » SRAM, EEPROM, Flash, ROM » data transfer on local bus » accessible only to CPU » allows CPU module to be independently tested – main memory in memory module » data transfer on system bus
• 12.
  Address and DataBus Buffers • uP output pins can only drive small load – a few nearby chips • Use buffers or bus drivers to drive large buses – chips with big transistors, little logic – shield uP from load • Interface between uP and local and system buses • Need buffer control to coordinate drivers
• 13.
  Buffer Control • Determinesoperating mode of bus drivers and receivers – only turn on drivers when they need to send data – e.g. disable system bus drivers during local memory access • Only one device can drive the bus at a time – tristate - buffer goes into high impedance state » like an open circuit • Operations on parts of a word – e.g. 32-bit uP wants to write one byte or a 16-bit word – memory has byte addresses • Byte/word control turns on drivers in part of bus
• 14.
  Bus Arbitration Control •Master and slave devices – CPU is master – memory and peripherals are slaves – CPU controls all bus usage • Multi-master system – multiple devices can access bus – DMA (direct memory access) controller » moves data between memory and peripheral » autonomous of CPU – multiprocessor - multiple uPs • Need protocol (rules) for bus access – one at a time, fair access, timely access – in hardware for speed – master - currently controlling bus – slave - devices accessed by master
• 15.
  Memory Management • Translate uPlogical address to memory physical address – logical address - any address in uP architecture address space » issued by program – physical address - actual memory location • Virtual memory – make small physical memory look like large logical memory – store part of data on disk – system vs. user protection domains • Location independence – programmers use logical address – operating system figures out what physical address to use • Memory management unit (MMU) – part of CPU today - 68030, 486, and later
• 16.
  Memory Module • Typesof memory – read/write random access memory (RAM) – read-only memory (ROM) » programmed when manufactured » use for bootstrap programs, fixed code » example: PostScript interpreter – EPROM, EEPROM, flash » program once, or once in a while » use for program storage, preferences • Interface – bus interface - buffers, buffer control – address decoders – refresh logic
• 17.
  Memory Module (cont.) •Dynamic RAM (DRAM) – lowest cost/bit - 1 transistor+capacitor per bit – used for large main memories – must refresh bits every few milliseconds • Static RAM (SRAM) – faster – more expensive - 6 transistors per bit – often used for cache memory – often used for battery applications » holds data at very low power
• 18.
  Peripheral Module • Interfacesto outside world • Serial input/output (I/O) – terminal line • Parallel I/O – printer cable • Timer – measure time – generate series of pulses - e.g. interrupt uP at fixed interval – used for real-time systems • Disk controller – disk operations – data format conversion • Network interface – Ethernet, IEEE 488 bus, etc.
• 19.
  ColdFire MCF5206e