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PIC is a family of modified Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC1650〔http://ww1.microchip.com/downloads/en/DeviceDoc/39630C.pdf〕〔http://www.datasheetarchive.com/dl/Databooks-1/Book241-407.pdf〕〔"PICmicro Family Tree", PIC16F Seminar Presentation http://www.microchip.com.tw/PDF/2004_spring/PIC16F%20seminar%20presentation.pdf〕 originally developed by General Instrument's Microelectronics Division. The name PIC initially referred to ''Peripheral Interface Controller''.〔"MOS DATA 1976", General Instrument 1976 Databook〕〔"1977 Data Catalog", Micro Electronics from General Instrument Corporation http://www.rhoent.com/pic16xx.pdf〕 The first parts of the family were available in 1976; by 2013 the company had shipped more than twelve billion individual parts, used in a wide variety of embedded systems. Early models of PIC had read-only memory (ROM) or field-programmable EPROM for program storage, some with provision for erasing memory. All current models use Flash memory for program storage, and newer models allow the PIC to reprogram itself. Program memory and data memory are separated. Data memory is 8-bit, 16-bit and in latest models, 32-bit wide. Program instructions vary in bit-count by family of PIC, and may be 12, 14, 16, or 24 bits long. The instruction set also varies by model, with more powerful chips adding instructions for digital signal processing functions. The hardware capabilities of PIC devices range from 8-pin DIP chips up to 100-pin SMD chips, with discrete I/O pins, ADC and DAC modules, and communications ports such as UART, I2C, CAN, and even USB. Low-power and high-speed variations exist for many types. The manufacturer supplies computer software for development known as MPLAB, assemblers and C/C++ compilers, and programmer/debugger hardware under the MPLAB and PICKit series. Third party and some open-source tools are also available. Some parts have in-circuit programming capability; low-cost development programmers are available as well has high-production programmers. PIC devices are popular with both industrial developers and hobbyists due to their low cost, wide availability, large user base, extensive collection of application notes, availability of low cost or free development tools, serial programming, and re-programmable Flash-memory capability. ==History== The original PIC was built to be used with General Instrument's new CP1600 16-bit Central processing unit (CPU). While generally a good CPU, the CP1600 had poor I/O performance, and the 8-bit PIC was developed in 1975 to improve performance of the overall system by offloading I/O tasks from the CPU. The PIC used simple microcode stored in ROM to perform its tasks, and although the term was not used at the time, it shares some common features with RISC designs. In 1985, General Instrument spun off their microelectronics division and the new ownership cancelled almost everything — which by this time was mostly out-of-date. The PIC, however, was upgraded with an internal EPROM to produce a programmable channel controller. Today, a huge variety of PICs are available with various on-board peripherals (serial communication modules, UARTs, motor control kernels, etc.) and program memory from 256 words to 64k words and more (a "word" is one assembly language instruction, varying in length from 8 to 16 bits, depending on the specific PIC micro family). PIC and PICmicro are registered trademarks of Microchip Technology. It is generally thought that PIC stands for Peripheral Interface Controller, although General Instruments' original acronym for the initial PIC1640 and PIC1650 devices was "Programmable Interface Controller".〔 The acronym was quickly replaced with "Programmable Intelligent Computer".〔 The Microchip 16C84 (PIC16x84), introduced in 1993, was the first Microchip CPU with on-chip EEPROM memory. By 2013, Microchip was shipping over one billion PIC microcontrollers every year.〔 Microchip press release. ("Microchip Technology Delivers 12 Billionth PIC® Microcontroller to Leading Motor Manufacturer, Nidec Corporation" ). 2013. 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「PIC microcontroller」の詳細全文を読む スポンサード リンク
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