Alternatives Evaluation

Introduction

The HCS12 μProcessor from Freescale, the PIC24 μProcessor from Microchip, and the Amtel Atmega 2560 μProcessor were evaluated for suitability for gathering, recording and then playing back sensor data. All three μProcessors had mostly similar capabilities, but a few important differences. The number of A/D interfaces on the Freescale based μProcessor disqualified the HCS12 μProcessor. Then by weighing the design criteria, the differences between the PIC24 and the Atmega 6250 were used in selecting the PIC24F μProcessor from Microchip.com

Design Alternatives

HCS12 μProcessor from Freescale.com.

The Freescale family of microprocessors are well known and used in various classes at MSU. The HCS12 is a 16-bit processor used in EELE 371 and is well suited for this project. The only problem is that it does not have enough A/D input channels as required by this project, so it will not work.

PIC24F μProcessor from Microchip.com.

The Microchip family of microprocessors have several 8-bit and 16-bit versions, but the one selected for prototyping is the PIC24 16-bit processor with256KB programmable flash memory. The pertinent specifications follow:

Table 1: PIC24 Microprocessor Specifications

Figure 5.1 � Picture of packaging used for the PIC24F

Mega2560 μProcessor from Arduino.cc.

The Arduino family of μProcessors uses various Atmel processors. The most advanced being the Atmega 2560 processor. The pertinent specifications follow:

Table 2: Mega2560 Microprocessor Specifications

Client/User Operation

Design Matrix

Weighing the main differences between the competing processors on a scale of 0-10 and then scoring each processor on a scale of 0-10, multiplying the weight by the scale and then summing all the products gives a weighted score for each processor. A perfect score for a processor is 440 points. Neither got perfect scores, but the Microchip PIC24F processor got a much better score of 377 versus 325, which leads to deciding that the Microchip PIC24F processor should work better for this application.

Table 3: Descision Matrix