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 Resources
©1999 Joseph Birr-Pixton email: jbp@cheerful.com |
Microchip History Microchip Technology incorporated was started by a group of venture capitalists who saw potential in the semiconductor division of General Instruments. General Instruments, which produced various electronic components, many years ago developed a series of programmable, high output current, input/output controllers. They called them Peripheral Interface Controllers, or PICs. They were actually simple microcontrollers built around a RISC (reduced instruction set code) architecture. They ran efficiently at 1 instruction per clock cycle at a high oscillator frequency of 20 MHz. This made PICs relatively fast for an 8-bit micro, but their main feature was 20 ma of source and sink current capability on each I/O pin. Typical micros of the time were advertising high I/O currents of 1 ma source and 1.6 ma sink. For some business reason, General Instruments decided that the semiconductor division was not worth keeping and sold the operations (along with the factory in Chandler, Arizona) to the venture capitalists. This group formed what is now known as Microchip Technology. Those PICs became the main components offered by Microchip. Initially the selection of parts was small, and none of the parts had some common micro features like interrupts. They also used a somewhat unusual banking arrangement for memory that still exists today in many of Microchip's parts. Despite these limitations, the parts sold well and allowed Microchip to develop new components with new features including interrupts, on-board A/D, on-board comparators, and more. Microchip's lineup soon included flash memory parts as well as low cost OTP (one time programmable) parts. This low cost OTP feature set Microchip apart from their competitors. Other 8-bit micro companies offered OTP's but they usually came at a high price premium to the masked ROM (read only memory) version. Masked ROM micros are built by placing layers of semiconductor atop each other to form the transistors and other components that make up a micro. The proper arrangement makes the micro operate according to the software. After a masked ROM is created, it cannot be changed. One single software command change requires a new masked ROM. Microchip found a way to produce OTP's at only a small cost premium over their masked ROM parts. This allowed designers to use OTP's in final designs so small changes could be made without stopping production or spending more money for a new masked ROM. Microchip also made the parts serially in-circuit programmable. This allowed a manufacturer to build up electronic modules with an unprogrammed PIC on board and then program it right on the factory floor. That flexibility, along with the other features, made Microchip popular with professionals and experimenters. Microchip has since grown to become the second largest producer of 8-bit microcontrollers. PIC History The PIC (peripheral interface controller) was developed in the early '90s by Arizona microchip to meet a demand for a cheap, small and practical microcontroller which was both easy to use and program. The thing that made the PIC so successful was the fact that it was so small compared to the other options available on the market at the time. For example:
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