• • • • • • • • • • • • • • • • • • • • • • • • • A microcontroller is meant to be more self-contained and independent, and functions as a tiny, dedicated computer. The great advantage of microcontrollers, as opposed to using larger microprocessors, is that the parts-count and design costs of the item being controlled can be kept to a minimum. They are typically designed using CMOS (complementary metal oxide semiconductor) technology, an efficient fabrication technique that uses less power and is more immune to power spikes than other techniques. Microcontrollers are sometimes called embedded microcontrollers, which just means that they are part of an embedded system that is, one part of a larger device or system. Controller: A device that controls the transfer of data from a computer to a peripheral device and vice versa. For example, disk drives, display screens, keyboards and printers all require controllers. In personal computers, the controllers are often single chips. When you purchase a computer, it comes with all the necessary controllers for standard components, such as the display screen, keyboard, and disk drives. If you attach additional devices, however, you may need to insert new controllers that come on expansion boards. Controllers must be designed to communicate with the computer's expansion bus. There are three standard bus architectures for PCs - the AT bus, PCI (Peripheral Component Interconnect ) and SCSI. When you purchase a controller, therefore, you must ensure that it conforms to the bus architecture that your computer uses. Short for Peripheral Component Interconnect, a local bus standard developed by Intel Corporation. Most modern PCs include a PCI bus in addition to a more general IAS expansion bus. PCI is also used on newer versions of the Macintosh computer. PCI is a 64-bit bus, though it is usually implemented as a 32 bit bus. It can run at clock speeds of 33 or 66 MHz. At 32 bits and 33 MHz, it yields a throughput rate of 133 MBps. Short for small computer system interface, a parallel interface standard used by Apple Macintosh computers, PCs, and many UNIX systems for attaching peripheral devices to computers. Nearly all Apple Macintosh computers, excluding only the earliest Macs and the recent iMac, come with a SCSI port for attaching devices such as disk drives and printers. SCSI interfaces provide for faster data transmission rates (up to 80 megabytes per second) than standard serial and parallel ports. In addition, you can attach many devices to a single SCSI port, so that SCSI is really an I/O bus rather than simply an interface Although SCSI is an ANSI standard, there are many variations of it, so two SCSI interfaces may be incompatible. For example, SCSI supports several types of connectors. While SCSI has been the standard interface for Macintoshes, the iMac comes with IDE, a less expensive interface, in which the controller is integrated into the disk or CD-ROM drive. The following varieties of SCSI are currently implemented: SCSI-1: Uses an 8-bit bus, and supports data rates of 4 MBps.
• • • • • • • • • • • • SCSI-2: Same as SCSI-1, but uses a 50-pin connector instead of a 25-pin connector, and supports multiple devices. This is what most people mean when they refer to plain SCSI. Wide SCSI: Uses a wider cable (168 cable lines to 68 pins) to support 16-bit transfers. Fast SCSI: Uses an 8-bit bus, but doubles the clock rate to support data rates of 10 MBps. Fast Wide SCSI: Uses a 16-bit bus and supports data rates of 20 MBps. Ultra SCSI: Uses an 8-bit bus, and supports data rates of 20 MBps. Wide Ultra2 SCSI: Uses a 16-bit bus and supports data rates of 80 MBps. SCSI-3: Uses a 16-bit bus and supports data rates of 40 MBps. Also called Ultra Wide SCSI. Ultra2 SCSI: Uses an 8-bit bus and supports data rates of 40 MBps. Embedded system: A specialized computer system that is part of a larger system or machine. Typically, an embedded system is housed on a single microprocessor board with the programs stored in ROM. Virtually all appliances that have a digital Interface- watches, microwaves, VCRs, cars -utilize embedded systems. Some embedded systems include an operating system, but many are so specialized that the entire logic can be implemented as a single program. MICRO CONTROLLER MICRO PROCESSER • It is a single chip • Consists Memory, I/o ports • It is a CPU • Memory, I/O Ports to be connected externally CP CPU MEMORY I/O PORTS
8085 Microprocessor ContentsGeneral definitions Overview of 8085 microprocessor Overview of 8086 microprocessor Signals and pins of 8086 microprocessor • • • The salient features of 8085 µp are: It is a 8 bit microprocessor. It is manufactured with N-MOS technology. It has 16-bit address bus and hence can address up to 216 = 65536 bytes (64KB) memory locations through A0-A15. • The first 8 lines of address bus and 8 lines of data bus are multiplexed AD 0 – AD7. • Data bus is a group of 8 lines D0 – D7. • It supports external interrupt request. • A 16 bit program counter (PC) • A 16 bit stack pointer (SP) • Six 8-bit general purpose register arranged in pairs: BC, DE, HL. • It requires a signal +5V power supply and operates at 3.2 MHZ single phase clock. • It is enclosed with 40 pins DIP (Dual in line package). Overview of 8085 microprocessor 8085 Architecture • Pin Diagram •
Microprocessors and Microcontrollers/Architecture of Microprocessors RES 5. 5 INTA RES 6. 5 RES 7. 5 TRAP SID Lecture Notes SIO INT SERIAL I / O CONTROL INTERRUPT CONTROL 8 BIT INTERNAL DATA BUS ACCUMULATOR INSTRUCTION (8) TEMP REG REGISTER (8) FLAG ( 5) FLIP FLOPS INSTRUCTION DECODER AND MACHINE ENCODING ARITHEMETIC LOGIC UNIT ( ALU) +5V (8) MULTIPLXER (8) R E G . S E L E C T W(8) TEMP. REG. C REG ( 8 ) B REG ( 8 ) D REG ( 8 ) E REG ( 8 ) H REG ( 8 ) STACK POINTER L REG ( 8 ) ( 16 ) PROGRAM COUNTER ( 16 ) INCREAMENT / DECREAMENT ADDRESS LATCH ( 16 ) GND X1 CLK TIMING AND CONTROL ADDRESS BUFFER ( 8) GEN X2 CONTROL CLK OUT READY RD WR ALE DMA STATUS S0 S1 RESET IN RESET OUT DATA / ADDRESS BUFFER ( 8 ) A 15 – A8 ADDRESS BUS IO / M HOLD HLDA AD7 – AD0 ADDRESS / BUFFER BUS Block Diagram Flag Registers D7 D6 S Z D5 D4 D3 D2 AC D1 P CY General Purpose Registers INDIVIDUAL B, C, D, E, D0 H, L