Palm Programming: GPS receiver
This paper looks at the process of developing an application for a device running a Palm operating system; specifically, any device running OS 3.x or newer. The main focus is broken into two separate ideas: understanding the process flow and minimum requirements of any Palm application and the development of a program to receive and display data gathered from a Garmin GPS 25 LVC receiver unit. All of the programs, processes, and ideas contained herein are based on the use of CodeWarrior, a developer's environment for the PC available as freeware from Metrowerks Corporation.As with any programming environment, the programmer must first learn the basics of how the computer functions. Most programmers are familiar with the PC environment and standard flow of an application. When programming in any language on a PC, the developer must create and include any functions or additional files that are necessary for use with the application being created. However, the Palm OS is slightly different, and rightfully so considering the limited storage capacity available on most handhelds. When a Palm application is being developed, many of the functions that are going to be needed for performing the most comm
The program does gather data and display it properly but the device must be run through a soft reset when exiting the application by pressing the on screen reset button. The user interface for this program appears on page 5 in Figure 1. When the program is running and the search for data is complete, the original search label is erased and one of the strings are called and inserted in its place. are each anchored to a specific form and are only visible and active when that particular for is displayed on the screen. The third file in the project is the function library that is stored in the Metrowerks directory on the PC. That is, if the program is run with no module attached to it (obviously there will be no data) it opens and closes correctly with no failure. If this string is found, the sentences in the buffer are broken up into single characters and placed in an array for easy access to the strings. This main form acts as the backdrop for all of the actions that will occur in the program. After this data is received it is checked for validity by searching for a specific string that is the first byte of any valid transmission from the receiver unit. The actual source code generated by the project stationary is included in Appendix A. Each alert is a standard size and appears at the bottom of the screen. CodeWarrior generates this file when the resource file is constructed. 0 or better returning an error if it is not and closing the application. Under the assumption that there was likely a programming error the code was modified and rearranged into several different configurations to attempt to remedy the problem. This functions as a visual editor of exactly what the user interface (UI) will look like when the program is completed.
Common topics in this essay:
Function ReadSerial,
Searching GPS,
Project Structure,
Constructor Figure,
PilotMain EventLoop,
GPS Program,
Finishing Application,
Palm OS,
PilotMain RomVersionCompatible,
Palm C/C++,
serial port,
event loop,
main form,
user interface,
source code,
gps program,
source file,
resource file,
figure 1,
called pilotmain,
user interface elements,
created serial port,
messages created serial,
file resource file,
static labels created,
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Acceptance Essays
