EE 5340/7340 Biomedical Instrumentation Laboratory 4:

Serial Port Design

Our goals in this lab are to:

1. Familiarize ourselves with the Motorola 68HC11 microcontroller, addressing modes, and assembler directives.
2. Become familiar with the Axiom debugger and monitor.
3. Learn how the serial port on the 68HC11 works.
4. Understand the program “Hello.asm”

We can begin by looking at the following slides to get a quick introduction to the 68HC11. Next, it will be useful to look over the manual for the evaluation board we will use, the CME11E9-EVBU. If you have not had experience with assembly language programming, you may want to do the following simple tutorial. Otherwise, go on to the tutorial found in the manual. Once you have gotten your tutorial to work, then read Section 9 of the 68HC11 reference manual to become familiar with the operation of the asynchronous serial port. Once you are familiar with the serial port, then go back and carefully study the program “hello.asm” used in the tutorial. In your lab write-up, explain in detail what each of the lines of code in “hello.asm” are doing.

Here are some additional resources to learn about the basics of serial communications:

1. http://www.camiresearch.com/Data_Com_Basics/data_com_tutorial.html
2. http://www.smarthomeusa.com/books/habc.pdf

Appendix A of the 68HC11 reference manual contains additional information about the instruction set and addressing modes.