Members: Mark Chew, Meng Li, Robin Lin, Roger Shih, Yuet Suen (West)
There is more information on the Motorola Microcontroller here
The objective of this project is to build a portable electronic speaking device that is capable of playing pre-recorded short messages, such as "may I have a ticket" or "can I get a Coke please", so that handicapped people incapable of speech can have an easier time by themselves in public places.
This project involves the utilization of a microchip built by Motorola, an external memory, and an ISD sound chip all assembled on a Motorola evaluation board. We would like to utilize these easy to use components along with a user interface in the form of a keypad so that short messages can be recorded and replayed in an efficient manner.
We hope to take advantage of the easily programmable Motorola microchip to avoid the nitty gritty details of hardware design. This way, the project can be accomplished by writing C programs and use pre-built compilers and assemblers to translate into assembly code that can be directly used by the microchip. However, in order to have the versatility of programming in C, we had to add an external RAM to supplement the insufficient on board RAM inside the microchip.
We have assembled on the Motorola evaluation board the microchip, external RAM and ISD sound chip. In addition, we have also attached a four to eight button keypad as the user interface. Of course, we hope the end product will not be such a bulky device, but for testing purpose it is unavoidable. The way the device works is that the user will choose three operating modes: off, record, play. In record mode, by pressing one of the numbered buttons, the user can record a short message such as "may I have a ticket." After having recorded for all the numbered buttons and becoming familiar with which particular button is associated with which message, the user can confidently go out in public and switch the device to play mode and play the pre-recorded messages when necessary.
Four to eight button keypad will be the chosen user interface simply because it's easy to work with and easy to use. One button will be used to switch among the three modes: off, record, play. All other available buttons can be used as numbered buttons to record and play messages. Four button device means there will be the capacity to record three messages, whereas eight button devices means the user may record seven messages.
A Buffalo compiler is a high level language that combines the programming ease of an interpreter with greater speed. This is accomplished by translating the C program (on a host machine such as a desktop PC) directly into machine language. The machine language program is then burned onto an EPROM or downloaded directly to the microcontroller. The microcontroller then executes the translated program directly, without having to interpret first.
C is now the language of choice for the entire universe. C is used on computers from the tiny microcontroller up to the largest Cray supercomputer. Although a C program can be a bit tedious at times to read (due to the terse programming style followed by many C programmers), it is a powerful and flexible development tool. Although a high level language, it also gives the developer access to the underlying machine. There are several very good and cheap C compilers available for the more popular microcontrollers. It is widely used, available, supported, and produces fairly efficient code (fast and compact).
An assembly machine language program is fast and small. Since no one in our group really know how to program in assembly language, we are using buffalo compiler to translate C language to Assembly language. So, we can take advantage of the assembly language to program the microcontroller.
For this semester, we agreed on a basic user-interface for the speaking device including a telephone-style keypad that will include record, on, erase, and message-number keys. The play button will be incorporated into the message-number keys in order to maintain ease of use. Since the speaking device will be designed for easy use by those with disabilities, we decided to use large individual keys.
The next task is to program the microcontroller in C and using the aforementioned C/Buffalo compiler. We will need to program the microcontroller so that it will be able to access information stored in the sound chip as well as being able to understand input from the user interface.
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