LIFE IN today’s time is improving leaps and bounds as far as technological innovation is concerned. All this has been made possible due to that small piece of wonder, the ‘microprocessor’. The microprocessor, with its humble beginning has transformed in to a very complex device with applications extending from the most trivial of daily life gadgets to super computers capable of performing astronomical calculations. The need for smaller and efficient designs required that the microprocessor be available in a compact version thus giving birth to microcontrollers. Microcontrollers have found a vast array of applications as far as day to day affairs are concerned, doing jobs that make our lives more convenient and safer.
The PIC (Peripheral Interface Controller) microcontroller series manufactured by Microchip Inc provides the user with a large variety of options which give the user a head start in developing embedded applications with over 400 microcontrollers to choose from. In fact, according to Microchip Inc, it shipped its 6th billionth PIC microcontroller in 2008, that’s 1 for every person on earth. Microchip has several flavors that it offers in terms of computational capability, pin count and integrated features.
The baseline series consists of some of 10F, 12F and 16F PIC microcontrollers. They provide users with low pin count, medium processing capabilities and a cheap solution by starting at only $0.33. They are used for commercial systems where prototyping is carried out once followed by commercial manufacturing.
The next series in the 8 bit architecture is called the Midrange series. The midrange series encompasses 12F and 16F series controllers including the all so famous 16F84 PIC microcontroller. The Midrange series allows the user to strike a compromise between integrated peripherals such as built in Analog to Digital (ADC) converter modules, Serial Interface Bus (SPI), Inter-Integrated Circuit (I2C) module and Enhanced Universal Synchronous and Asynchronous Transmitter Receiver (EUSART) Module for communicating with the computer. They provide a cheap option with relatively high pin count and integrated accessories.
The next series i-e the Enhanced Midrange Series has been developed recently and contains some new 12F and 16F series processors. Microchip offers these in low power types as well. Multiple peripherals are offered.
The high end devices consist of the 18F series of microcontrollers that tend to the needs of microcontroller enthusiasts and system developers alike, featuring options such as built in Ethernet, Controller Area Network (CAN) and USB modules in addition to the peripherals available in other flavors. Some of these microcontrollers also have a built in LCD driver.
There is also a Radio Frequency series of 8 bit PIC microcontrollers known as rfPICs that have built in ASK and FSK Transmitters, only requiring an antenna for wireless communication. Microchip also produces a class of 16 bit PIC microcontrollers and ones that are dedicated for Signal Processing known as dsPIC or Digital Signal Controllers that can work directly with softwares such as Matlab to reduce the development time. The last type of PIC microcontrollers is the PIC32, which provides a 32 bit core for applications that require complex processing algorithms, these come with built-in USB, and Ethernet modules as a standard along with supplementary flavors featuring CAN modules and Parallel Master/Slave port for connecting external memory.
The development tools for all of the PIC microcontrollers are provided by microchip for a nominal price, besides most of the development tools are open ended for e.g most of their kits and programmers can be cloned with easily available parts. Libraries and design guides are available to use the many functions that PIC microcontrollers lay at the user’s disposal. Programming in supported in a variety of languages stretching from Assembly, Basic, C to Flowchart programming.
PIC microcontrollers have been widely used for developing applications ranging from a simple clock to industrial automation systems for motor control, digital power conversion, graphics display, speech and sound processing, lighting solutions, automobiles, touch sensing applications for home automation, medical devices such as ECG machines, oxygen concentrators etc. They have also been used in smart sensor systems for monitoring purposes in remote areas using microchip’s own wireless modules exhibiting very low power consumption and very little cost. Thus PIC microcontrollers provide a cost optimal solution to DIY project development as well as automation problems. There is a great need to impart technical knowledge about PIC microcontrollers based embedded systems in our engineering and technological educational and research institutions in the country. It is believed that such technical expertise will lead the country towards low cost indigenous industrial automation.
Authors are faculty members of Department of Electronic and Biomedical Engineering, Mehran University of Engineering and Technology, Jamshoro
http://www.technologytimes.pk/mag/2011/feb11/issue02/picking_the_processor.php
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