System-on-a-chip From Wikipedia, the free encyclopedia Jump to: navigation, search System-on-a-chip or system on chip (SoC or SOC) is an idea of integrating all components of a computer or other electronic system into a single integrated circuit (chip). It may contain digital, analog, mixed-signal, and often radio-frequency functions – all on one chip. A typical application is in the area of embedded systems. If it is not feasible to construct an SoC for a particular application, an alternative is a system in package (SiP) comprising a number of chips in a single package. SoC is believed to be more cost effective since it increases the yield of the fabrication and because its packaging is simpler. Contents [hide] • 1 Structure • 2 Design flow • 3 Fabrication • 4 See also • 5 External links [edit] Structure y513719001187192499 from [email protected] was published by D-Publish on August 15, 2007 Microcontroller-based System-on-a-Chip A typical SoC consists of: • One or more microcontroller, microprocessor or DSP core(s). • Memory blocks including a selection of ROM, RAM, EEPROM and Flash. • Timing sources including oscillators and phase-locked loops. • Peripherals including counter-timers, real-time timers and power-on reset generators. • External interfaces including industry standards such as USB, FireWire, Ethernet, USART, SPI. • Analog interfaces including ADCs and DACs. • Voltage regulators and power management circuits. These blocks are connected by either a proprietary or industry-standard bus such as the AMBA bus from ARM. DMA controllers route data directly between external interfaces and memory, by-passing the processor core and thereby increasing the data throughput of the SoC. [edit] Design flow y513719001187192499 from [email protected] was published by D-Publish on August 15, 2007 System-on-a-Chip Design Flow A SoC consists of the hardware described above, and the software that controls the microcontroller, microprocessor or DSP cores, peripherals and interfaces. The design flow for an SoC aims to develop this hardware and software in parallel. Most SoCs are developed from pre-qualified blocks for the hardware elements described above, together with the software drivers that control their operation. Of particular importance are the protocol stacks that drive industry-standard interfaces like USB. The hardware blocks are put together using CAD tools; the software modules are integrated using a software development environment. A key step in the design flow is emulation: the hardware is mapped onto an emulation platform based on a field programmable gate array (FPGA) that mimics the behavior of the SoC, and the software modules are loaded into the memory of the emulation platform. Once programmed, the emulation platform enables the hardware and software of the SoC to be tested and debugged at close to its full operational speed. After emulation the hardware of the SoC follows the place and route phase of the design of an integrated circuit before it is fabricated. Chips are verified for logical correctness before being sent to foundry. The process is called ASIC verification. Verilog and VHDL are the Hardware Descriptive languages used for verification. With growing complexity of Chips HVLs like SystemVerilog, SystemC, e, Vera are used. The bugs found in the verification stage are reported to the y513719001187192499 from [email protected] was published by D-Publish on August 15, 2007 designer. Traditionally, 70% of time and energy in chip design life cycle are spent on verification. [citation needed] [edit] Fabrication SoCs can be fabricated by several technologies, including: • Full-custom • Standard cell • FPGA SoC designs usually consume less power and have a lower cost and higher reliability than the multi-chip systems that they replace. And with fewer packages in the system, assembly costs are reduced as well. However, like most VLSI designs, the total cost is higher for one large chip than for the same functionality distributed over several smaller chips, because of lower yields and higher NRE costs. [edit] See also • List of system-on-a-chip suppliers • PSoC • ASIC • Microcontroller • Electronic design automation • NES-on-a-chip [edit] External links • SoC Article Series • TSC electric power meter IC- a typical mixed-signal system on chip • MIPS-based SoCs at linux-mips.org • Embedded Processor and System-on-Chip Quick Reference Guide • System-on-a-Chip by www.SiliconFarEast.com • Navarre AsyncArt. Asynchronous System-on-Programmable-Chip Research & Services. Public University of Navarre • HybridThreads(Hthreads) Programmatically building semi-custom multiprocessor systems-on-chip using hybrid CPU/FPGA components. • Systems-on-chip using hybrid CPU/FPGA components. y513719001187192499 from [email protected] was published by D-Publish on August 15, 2007 Microcontroller From Wikipedia, the free encyclopedia Jump to: navigation, search It has been suggested that this article or section be merged with embedded microprocessor. (Discuss) The integrated circuit from an Intel 8742, an 8-bit microcontroller that includes a CPU running at 12 MHz, 128 bytes of RAM, 2048 bytes of EPROM, and I/O in the same chip. A microcontroller (or MCU) is a computer-on-a-chip. It is a type of microprocessor emphasizing self-sufficiency and cost-effectiveness, in contrast to a general-purpose microprocessor (the kind used in a PC). The only difference between a microcontroller and a microprocessor is that a microprocessor has three parts - ALU, Control Unit and registers (like memory), but the microcontroller has additional elements like ROM, RAM etc. Contents [hide] • 1 Embedded design • 2 Higher Integration • 3 Large Volumes • 4 Programming Environments • 5 Interrupt Latency • 6 History • 7 Development platforms for hobbyists o 7.1 Arduino o 7.2 Platforms from Parallax, Inc. o 7.3 PICAXE o 7.4 A-WIT Technologies, Inc. o 7.5 Comfile Technology Inc. y513719001187192499 from [email protected] was published by D-Publish on August 15, 2007 o 7.6 Coridium ARMexpress o 7.7 ZX-24, ZX-40, ZX-44 • 8 Notes • 9 See also • 10 External links • 11 External links [edit] Embedded design The maJority of computer systems in use today are embedded in other machinery, such as telephones, clocks, appliances, vehicles, and infrastructure. An embedded system usually has minimal requirements for memory and program length and may require simple but unusual input/output systems. For example, most embedded systems lack keyboards, screens, disks, printers, or other recognizable I/O devices of a personal computer. They may control electric motors, relays or voltages, and read switches, variable resistors or other electronic devices. Often, the only I/O device readable by a human is a single light- emitting diode, and severe cost or power constraints can even eliminate that. [edit] Higher Integration In contrast to general-purpose CPUs, microcontrollers may not implement an external address or data bus, because they integrate RAM and non-volatile memory on the same chip as the CPU. Because they need fewer pins, the chip can be placed in a much smaller, cheaper package. Integrating the memory and other peripherals on a single chip and testing them as a unit increases the cost of that chip, but often results in decreased net cost of the embedded system as a whole. (Even if the cost of a CPU that has integrated peripherals is slightly more than the cost of a CPU + external peripherals, having fewer chips typically allows a smaller and cheaper circuit board, and reduces the labor required to assemble and test the circuit board). A microcontroller is a single integrated circuit, commonly with the following features: • central processing unit - ranging from small and simple 4-bit processors to sophisticated 32- or 64-bit processors • input/output interfaces such as serial ports (UARTs) • other serial communications interfaces like I²C, Serial Peripheral Interface and Controller Area Network for system interconnect • peripherals such as timers and watchdog • RAM for data storage • ROM, EPROM, EEPROM or Flash memory for program storage • clock generator - often an oscillator for a quartz timing crystal, resonator or RC circuit y513719001187192499 from [email protected] was published by D-Publish on August 15, 2007 • many include analog-to-digital converters This integration drastically reduces the number of chips and the amount of wiring and PCB space that would be needed to produce equivalent systems using separate chips and have proved to be highly popular in embedded systems since their introduction in the 1970s. Some microcontrollers can afford to use a Harvard architecture: separate memory buses for instructions and data, allowing accesses to take place concurrently. The decision of which peripheral to integrate is often difficult. The Microcontroller vendors often trade operating frequencies and system design flexibility against time-to- market requirements from their customers and overall lower system cost. Manufacturers have to balance the need to minimize the chip size against additional functionality. Microcontroller architectures are available from many different vendors in so many varieties that each instruction set architecture could rightly belong to a category of their own. Chief among these are the 8051, Z80 and ARM derivatives.[citation needed] [edit] Large Volumes Microcontrollers take the largest share of sales in the wider microprocessor market. Over 50% are "simple" controllers, and another 20% are more specialized digital signal processors (DSPs) [citation needed]. A typical home in a developed country is likely to have only one or two general-purpose microprocessors but somewhere between one and two dozen microcontrollers. A typical mid range automobile has as many as 50 or more microcontrollers. They can also be found in almost any electrical device: washing machines, microwave ovens, telephones etc. A PIC 18F8720 microcontroller in an 80-pin TQFP package. Manufacturers have often produced special versions of their microcontrollers in order to help the hardware and software development of the target system.
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