Val's MC68HC11 Emporium

This page is dedicated to the users of the Motorola MC68HC11 microcontroller chip. Its purpose is to openly contribute hardware design and code to those who may find this information useful. Everything you see here is original work, designed by the author (except where noted), and is free for the taking. Hopefully, it makes up in content what it lacks in pizzazz.

File Name Description Size Interrupt driven communications interface. This code uses the SCI port in interrupt mode thereby eliminating the continuous polling required by other methods. This document includes a description of most of the subroutines found in the software.  30KB Multi-tasking dispatcher. This document describes a method by which a multi-tasking system can be implemented for microprocessor applications without undue overhead associated with full-blown operating systems. 55KB Loader program for the MC68HC711D3 microprocessor. By burning-in this program into the EPROM or OTPROM, the hardware becomes a development system. Code can be downloaded into RAM for testing repeatedly without having to resort to continuous erase and burn cycles. 6KB Complete design of a digital clock with RS-232 interface. This document describes the protocol of the commands and data sent over the interface for setting the clock timer and for retrieving the clock date and time. The complete source code is included both for an EPROM implementation and for testing in RAM. 212KB
 Clock.exe This program, written in Borland's Delphi is used to communicate with the digital clock above. It can be used to set the date and time of the clock from a fixed input or from the PC system clock directly. It can also retrieve the date and time and set the PC system clock. 377KB Software Serial Interface. When you need a second serial interface you can make one up by using one port input and one port output pin. This code, however, operates on an interrupt basis freeing up the CPU for other tasks.  135KB The Dallas Semiconductor DS1820 is a digital thermometer which requires no analog circuitry for its operation. The 1-wire interface can be implemented using one bi-directional bit of the microprocessor I/O. 36KB This code demonstrates the use of an external UART driving a RS-485 interface. It is the slave end of a master-slave combination. It responds to commands from the master according to the Half-Duplex Protocol described in the documentation. 194KB This code shows how to implement a keyboard scanner with n-key rollover. The hardware implementation uses a Programmable Logic Device from Xilinx (formerly Philips). The CoolRunner PLD technology uses very little power while maintaining high speed. For more information check out the Xilinx site. 344KB This example consumes two output compare timers and one input capture register to implement a full-duplex software serial interface. In addition to demonstrating the calls to the SSI services, the main routine can be used to enable/disable the COP circuit by programming the CONFIG register. 135KB Infrared Transmitter. This design is the transmitter portion of the infrared transmitter/receiver project. The transmitter sends codes for one of three push buttons. 86KB Infrared Receiver. This design is the receiver portion of the infrared transmitter/receiver project. The received codes can turn on one of three relays. 86KB In this example the MC68HC11 controls a high speed modem and communicates with a PC over the telephone lines. The SCI is used for the modem. Therefore, a second serial port, implemented in software, is used for messages and for downloading code during development. This code includes an example of a dynamic task that is started when needed and self-terminates when the job is done. 360KB This hardware and code is used to monitor a low frequency (60 Hz) electromagnetic field and provide a date and time stamp whenever the field comes on and goes off. When the data is retrieved by the PC, calculations can be made to determine the total power consumed by the monitored device. 120KB This program for the PC is written with Borland's Delphi and is intended to be used with the Flux Logger hardware above. The main source code module is included to show the PC side of the communications protocol. 893KB This code is an example of how to use the analog-to-digital converter of the HC11 in a multi-tasking environment. 128KB This is a program written in Delphi that can be used with the analog-to-digital example above to continuously read the A/D value from the hardware, transfer it over the serial port, and put the result into simulated analog meters. 162KB This circuit and program implement a sensor which uses eddy currents to detect the presence of metal objects entering and leaving the sensor zone. The example makes heavy usage of the HC11 internal timer and interrupt hardware. The resulting detection signals can be fed into a counter or used to switch external equipment for process control. 235KB This code was submitted by David Evans. CRC_V41 is a subroutine that encodes and decodes data blocks using the CCITT V.41 recommendation.  The subroutine uses a variable to specify whether data is decoded or encoded, and upon returning uses another variable so that the calling software can determine the status of the executed subroutine (e.g.: no errors or detected errors). The software has been written in a manner that allows it to be tailored to any HC11 system with any given data block length. All the information is in the software guide. 83KB

For more interesting sites re 68HC11 see Roger's Embedded Microcontrollers Home Page.
Also check out Peter Spasov's 68HC11 Microcontrollers Resources.


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