Problems

At the time of the submission the board was not functioning as intended, but the designers are confident that full functionality could be achieved given sufficient time for debugging of the board's hardware and software. The main difficulty encountered during the course of the semester was the time limitation of a one-semester class. While the semester afforded sufficient time for designing the board, not enough time remained at the end of the class for complete debugging of the board. The designers wholeheartedly recommended that this course be extended into a second semester in the future to enhance the probability of realizing fully functioning projects.

Unfortunately, debugging and programming efforts were stopped entirely as of Monday, April 30, 2001, due to a broken Cypress EZ-USB development board. Since there was only one development board to be shared among all the groups using the Cypress controller, code debugging and board functionality testing could not progress any further. Since communication among and control of all the individual subsystems on the eRaj board depend on software, there is no way to verify the board's functionality.

Before the development board ceased to function, several specific problems were identified in eRaj. First, the board was not receiving power to all the components when it was connected to a wall cube. Although the on-board power jack seemed to be seeing full voltage from the wall cube, the power was not being distributed properly to the 3.3V and 5V power planes.

Second, the memory interface was not fully operational, and debugging efforts in the interface control code indicated that an error in storage medium choice may be to blame. During preliminary design of the eRaj MP3 Alarm Clock, the SmartMedia format seemed to be a simple solution. The implementation required a seemingly minimal pin budget of 6 control pins and 8 data I/O pins. The control algorithm for reading and writing is relatively easy. Unfortunately, the pin budget may have taken too many of the programmable I/O pins of the EZ-USB such that the functionality was compromised. In the next version of the board, switching to a SanDisk MultiMedia card, which supports the SPI 4-wire communication protocol, could rectify the memory situation. This would further simplify the software aspects as well as reduce the pin budget.

Finally, the display was not fully functional due to conflicts in reference initialization procedures and timing requirements. A number of different initialization methods were being explored when development was halted due to the failing of the EZ-USB development board.

Conclusion

Even though the software and hardware debugging are incomplete, the eRaj MP3 Alarm Clock can be considered a success. The primary goal of this Elec 424 project was to produce a usable, marketable project that provided the opportunity to learn about high-speed digital design. Because much thought was given to concepts such as processors, memory, power management, and user interface, as well as the software needed to control the board, the eRaj MP3 Alarm Clock definitely accomplished this objective.

In terms of cost, this project actually came in slightly under budget. According to specifics given at the beginning of the year, each group was allocated $2500. Development of the eRaj project cost under $2200.

Of course, bulk pricing would cut the cost to nearly half this value, which would make this product a very viable, marketable option in the alarm clock market. With some further work to resolve the issues discussed earlier, the eRaj MP3 Alarm Clock can definitely become a major force in tomorrow's consumer electronics industry.

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