Monday, April 14, 2008

History of pic microcontrollers


The original PIC was built to be used with GI's new 16-bit CPU, the CP1600. 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 wasn't used at the time, it shares some common features with RISC designs.

In 1985 General Instruments 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off their microelectronics division, and the new ownership cancelled almost everything — which by this time was mostly out-of-date.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 EPROM to produce a programmable channel controller, and 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 512 words to 64k words and more (a "word" is one assembly language instruction, varying from 12, 14 or 16 bits depending on the specific PIC micro family).

Microchip Technology does not use PIC as an ; in fact the brand name is PICmicro. It is generally regarded 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".

Various older (EPROM) PIC microcontrollers
Various older (EPROM) PIC microcontrollers

The Microchip 16C84 (PIC16x84), introduced in 1993 was the first CPU with on-board EEPROM memory. This electrically-erasable memory made it cost less than CPUs that required a quartz "erase window" for erasing EPROM.


PIC microcontrollers in DIP and QFN packages
PIC microcontrollers in DIP and QFN packages
16-bit 28-pin PDIP PIC24 microcontroller with a metric ruler
16-bit 28-pin PDIP PIC24 microcontroller with a metric ruler


PIC is a family of Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC1640 originally developed by General Instrument's Microelectronics Division. The name PIC initially referred to "Programmable Interface Controller", but shortly thereafter was renamed "Programmable Intelligent Computer".

PICs are popular with developers and hobbyists alike due to their low cost, wide availability, large user base, extensive collection of application notes, availability of low cost or free development tools, and serial programming (and re-programming with flash memory) capability.

Microchip recently announced the shipment of its six billionth PIC processor.


1 comment:

Anonymous said...

Nice job dude,
Pranav Swaroop.