SECTION I-4: Criteria for Choosing a Micro-controllers

SECTION  I-4: Criteria for Choosing a Micro-controllers

There are 5 major 8-bit micro-controllers. They are...

  • Free scale Semiconductors formerly Motorola 68HC08/68HC11
  • Intel's 8051
  • Atmel's AVR, Zilog's Z8
  • PIC Microchip

The Above micro-controllers has a unique instruction set and register set. They are not compatible with each other. Programs written for one will not run on the others. there are also 16-bit and 32-bit micro-controllers.

What criteria do designers consider in Choosing one?

  1. Meeting the computing needs of the task at hand efficiently and cost effectively.
  2. Availability of software and hardware development tools such as compilers, assemblers, debuggers, and emulators.
  3. Wide availability and reliable sources of the micro-controllers.

1) Meeting the computing needs of the task at hand efficiently and cost effectively:

The first and foremost criterion in choosing a micro-controllers is that it must meet the task at hand efficiently and cost effectively. In analyzing the needs of a micro-controller-based project, we must first see whether an 8-bit, 16-bit, or 32-bit micro-controller can best handle the computing needs of the task most effectively. Other considerations in this category are:

  • Speed: What is the highest speed that the micro-controller supports?
  • Packaging: Does it come in a 40-pin DIP, dual inline package or QFP quad flat package, or some other packaging format. This is important in terms of space, assembling, and prototyping the end product.
  • Power consumption: This is especially critical for battery-powered products.
  • RAM/ROM: The amount of RAM and ROM on the chip.
  • I/O Pins: The number of I/O pins and the timer on the chip.
  • Upgrade: Ease of upgrade to higher-performance or lower-power-consumption versions.
  • Cost per unit: Important in terms of the final cost of the product in which a micro-controller is used. Some micro-controllers cost 50 cents per unit when purchased 100,000 units at a time.

2) Availability of software and hardware development tools such as compilers, assemblers, debuggers, and emulators.

It is how easy to to develop micro-controller products around it. Including the availability of an assembler, debugger, a code-efficient C language compiler, emulator, technical support, and both in-house and outside expertise. The third party vendors, a supplier other than manufacturer, support for the chip is as good as, if not better than, support from the chip manufacturer.

3) Wide availability and reliable sources of the micro-controllers.

Its ready availability in needed quantities both now and in the future. For some designers this is even more important than the first two criteria. Currently, of the leading 8-bit micro-controllers, the 8051 family has the largest number of diversified suppliers. In the case of 8051, which was originated by Intel, several companies also currently produce the 8051. The Free scale or Motorola, Atmel, Zilog, and Microchip technology have all dedicated massive resources to ensure wide and timely availability of their products because their products are stable, mature, and single sourced. In recent years, companies have begun to sell Field-programmable Gate Array FPGA and Application-Specific Integrated Circuit ASIC libraries for the different micro-controllers.

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