June 16, 2002
June 16, 2002
June 19, 2002
7.884.1 - 7.884.9
New Life for the MC68HC11 Evaluation Board
Christopher R. Carroll, Rocio Alba-Flores, Fernando Rios-Gutierrez
Electrical and Computer Engineering University of Minnesota Duluth email@example.com, firstname.lastname@example.org, email@example.com
Abstract Motorola’s MC68HC11 microcontroller has been the mainstay of laboratories in introductory microprocessor courses across the country for about ten years. The Evaluation Board (EVB) for that processor has formed the basis for lab stations in most of those courses. The MC68HC11 is still probably the most popular and most capable 8-bit microcontroller in the marketplace today, so using that processor as the foundation for laboratories in microprocessor courses continues to be common.
As current lab stations age, however, lab exercises using them are becoming stale and repetitive. This paper describes a new lab station based on the MC68HC11 EVB with enhancements to support an alphanumeric keyboard, multidigit LED display, and, most interestingly, an alphanumeric CRT display that uses a standard composite video signal generated by the MC68HC11 lab station to produce a display of four rows of sixteen characters on a standard video monitor. These capabilities are achieved using a minimum of additional components added to the standard EVB. Most of the input/output (I/O) capabilities of the MC68HC11 microcontroller are employed in one way or another to implement the I/O features of this lab station. In particular, the Serial Peripheral Interface (SPI) in the MC68HC11, an I/O feature of the processor that often goes unused, is the primary means by which the video signal for the CRT monitor is generated. With both a keyboard and a CRT display directly controlled by the EVB, the need for an external terminal at the lab station is eliminated. The MC68HC11 itself can emulate a terminal through which the user interacts with a host computer for writing, assembling, and downloading programs written as student solutions to various laboratory exercises.
In this paper we describe the new lab station hardware, detailing the two additional TTL chips and handful of passive devices added to the EVB to implement the CRT video signal generation and other I/O features of the station. We also describe lab experiments and experience gained in actually using this lab station in our microprocessor class.
Proceedings of the 2002 American Society for Engineering Education Annual Conference & Exposition Copyright ã2002, American Society for Engineering Education
Alba-Flores, R., & Carroll, C., & Rios-Gutierrez, F. (2002, June), New Life For The Mc68 Hc11 Evaluation Board Paper presented at 2002 Annual Conference, Montreal, Canada. https://peer.asee.org/11147
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