Bailey O.H.Embedded systems.Desktop integration.2005

due to the integration of the editor and debugger within the C++BuilderX product. It is worth noting that the Intel C++ compiler is included with C++BuilderX.

C++BuilderX scores slightly higher alone than when used with the Intel C++ compiler. This is due to the additional support for Microsoft C++ 6 and 7 and GNU C++ (3.2.3), and the inclusion of the Intel C++ compilers for Windows and Linux. In both evaluations we used wxWindows as the cross-platform GUI builder of choice.

We wrap the highest scores up with Delphi/C++Builder/ Kylix for Windows/Linux. These products work identically when using the CLX (Cross-platform Libraries) on Windows and Linux. No other tools include a compiler, debugger, visual designer, and visual libraries for both platforms with support for a singlesource code base.

And the Winners Are…

We are going to take two different approaches for the prototype development. Our first approach is to use commercial products

— the Delphi/C++Builder/Kylix combination. By using the visual design capabilities of these products and the cross-plat- form support for the visual components, the majority of our work has been greatly reduced. Our second approach is to use the personal version of C++BuilderX with the GNU compiler suite, and wxWindows. In deciding to use wxWindows there were several factors to consider. Qt, wxWindows, GTK+, and Zinc are all great tools. While Zinc is very well documented and mature, it is not currently being publicly supported and that means any problems encountered will be left to our developers to fix. Qt is also a great product with excellent documentation and support. If we needed support for the Macintosh, this would certainly give Qt an edge, but to produce the prototype we want to keep our costs down. Remember, we have not decided at this point if the same tools used in the prototype will also make the final product. If we choose to sell a prototype and use the noncommercial version of

requirements play a big role in the tools needed to do the job right. Had our requirements been different, the tools selected for our workbench would also have been different. The next chapter is a recap of our design.

Chapter 6

Final Design

Overview

Everything we’ve learned so far will be applied in this chapter. The result will be the master design document and master flowchart. This will serve as a summary of Chapters 1 through 5. The next chapter begins Part II, where we will build the embedded system and actually integrate it to the host systems.

Master Design Document

Purpose

This document will serve as the verbal road map through the development process. It provides the guidelines and standards to which the end product will be developed and measured. We will begin with the design definition of the embedded system, followed by the host interfaces, host integration design, user application design, and protocol design. Each interface will be covered in depth, as will hardware definitions and component selection for each chosen processor. The master flowchart will follow the design documentation.

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USB-232M from FTDI

PIC 16C765 from Microchip

EZ-USB from Cypress MicroSystems

Each of these devices has a different cost or development benefit associated with its use.

Three different approaches using two different types of Ethernet hardware will be used. They are:

Ethernet Development System from NetBurner

Embedded Ethernet from Systor

The NetBurner product uses an AMD Ethernet chip coupled with a Motorola Coldfire processor. While using a second processor may seem redundant, this does provide expansion capabilities. Again, we have chosen this as a launch pad for our prototype. There are several other microprocessor manufacturers that have embedded Ethernet. The choice was made by a combination of costs, functionality, and usable features for our product. We have consciously chosen to use microcontrollers instead of microprocessors due to pin count and intelligence. While microprocessors offer more in intelligence and expandability, they also contain much more power than needed in this project. Due to the added complexity, simpler products were chosen as a development platform.

Temperature Measurement

Since a major function of this device is temperature measurement and the ability to read multiple temperature sensors, the Dallas DS1822 1-Wire sensor was chosen for the prototype. This device was chosen because it is a part of the 1-Wire network product line that allows multiple devices to be attached to a single pair of wires. The 1-Wire scheme also allows additional sensors to be added on the same bus, conserving components and board space. While the 1-Wire protocol is complex, it is reliable and other device types that support the 1-Wire bus can be added without additional hardware. In short, the 1-Wire is mostly

software dependent once the hardware interface has been refined. Other 1-Wire temperature sensors can replace the DS1822, providing higher temperature resolution without any hardware changes. This allows us to offer a variety of products with varying degrees of temperature accuracy without any hardware changes at all.

Output Display

The system communicates with the user through a 2-line by 20-character LCD display. A keypad is used to edit and update system parameters. There are also two LEDs for displaying temperature alarm and power conditions. A red LED is turned on when a temperature limit has been exceeded. A green LED indicates that external power is being provided to power the unit.

User Input

User input is accomplished via a seven-key keypad. There are three control keys and four cursor keys. The control keys are:

Function/Menu

Set/Select

Clear

The four cursor keys are defined as:

Up Arrow/Increase

Down Arrow/Decrease

Left Arrow

Right Arrow

Chapter 6

Command Mode

To view or change a setting, the user will press and hold the Function/Menu key for five seconds. When command mode is entered the unit will sound a single beep through the internal speaker. Command mode is exited automatically upon 30 seconds of keyboard inactivity. Any changes not saved with the Set key are lost upon leaving command mode.

Menu Navigation

Once command mode is entered, a main menu will be displayed. Each menu selection is identified by a single uppercase letter. The currently defined selections are:

Time — Set time of day

Date — Set current date

Interface — Choose host interface

High Temperature — Set high temperature alarm

Low temperature — Set low temperature alarm

Exit Command Mode — Return to display mode

Sensor Reset — Reset temperature sensor network

Unit Reset — Reset entire unit

Cursor movement is obtained via the up, down, left, and right arrow keys as shown in Figure 6-1.

Figure 6-1

To change or view a specific function, press the left or right arrow keys to highlight the letter that identifies the chosen function and press the Set button. A new menu will be displayed with only function-dependent features.

Following is an illustration of the control keys.