68HC11 Microcontroller

Build a low-cost learning board, HC-11 EVB for studying the MOTOROLA 68HC11A1 Assembly and C language programing. Downloadable Buffalo V3.4 through the use of Randy`s S19 Downloader. After reading the Mobile Robots Book, written by Joseph L. Jones and Anita M. Flynn, and get the Interactive-C file from ftp://cher.media.mit.edu, I found a very nice S19 downloader written by Randy Sargent. I started to download the pcode to my HC-11 board, and run Interactive C. No problem with my board, it works very nice...

Build a 32-bit power single board computer. The board fetures 68HC000 @ 8MHz, 256kB FLASH, 256kB SRAM. Available now schematic of DTACK and decoder that use CPLD. Finally I got the problem with the limited resource of 8-bit microprocessor. One of my experiment needs the computing power between 8-bit and 32-bit cpu. For 8-bit applications I used MCS51 and AVR. Whereas the 32-bit applications, I used embbeded PC running linux...

Build a timer with Motorola Nitron MCU and using ICC08 to develop c program. Loader schematic also included. New s-record for 8-pin 68HC908QT2! The fan has mechanical timer for 0-180mins. One day it broken. So I got the idea to use Nitron chip to replace the mechanical timer. Someone may ask me why so complicated timer made by microcontroller chip? Actually we can build a timer with 555 and a 14-stage cmos counter! The 555 runs astable with time constant controlled by RC and for long period timing we can divide the output frequency of 555 by a cmos counter...

This project demonstrates the use of 16x1 line LCD module to interface with Nitron 16-pin MCU, 68HC908QY4. The original idea came from one evening I went out with my son to the park near my home in Korat. The park has a nice walking way for people to exercise. I was wondering how long the distance is? I thought it would be nice if we know distance for one round. It seemed to me that it`s quite long, but I didn`t know exactly...

My sister asked me to help make the device to control nigh light at her new house in Korat. I thought, it `s time for Motorola MCU and better to have LCD and keypad for program and time settings. I am so fun using Nitron chip. It can run from +3V to +6V. The most important for battery operated is low voltage reset module. Figure 1shows the prototype of the Time Swicth V1.0. I made it with universal pcb and placed Nitron chip at the bottom layer. The output has two channels with optotriac. It can drive the resistive AC load directly...

This application note shows how to interface Motorola`s MC68HC11 family of microcontrollers to the LM12458 parallel data acquisition system (DAS). It is intended to give the reader a better understanding of the DAS and how it can be integrated in a mP/mC system. There is a brief description of the MC68HC11Ax and the LM12458. An example is provided that will illustrate how to use the DAS in a system where a specific sampling rate is desired, single-ended and differential measurements of multiple channels need to be made, and alarm conditions must be monitored...

This is a simple display controller. It can be controlled with a small microcontroller, such as MCS51, 68HC11, Z80, AVR and others. Several years ago, I found an article that controlling a TV with only a PIC micorcontroller, and I surprised to it. It is very interesting to attempt to synthesize video signal with a micorcontroller. However, it is not suitable for practical use because the microcontroller is occupied in synthesizing video signal, it cannot process any other operation. Therefore, this technic can be applied to a toy at the best. It is required a display controller to contorl the video monitor, so I designed and built a simple display controller for RGB monitor and TV monitor...

This is a simple display controller. It can be controlled with a small microcontroller, such as MCS51, 68HC11, Z80, AVR and others. Several years ago, I found an article that controlling a TV with only a PIC micro controller, and I surprised to it. It is very interesting to attempt to synthesize video signal with a micro controller...

The MiniBoard, a Motorola 68HC11 Robot Controller board designed by Fred G. Martin, also uses this driver. The day after, I then decided to prepare the page describing how to use C-52 EVB as a robot controller board. I asked my student for competition, build yourselves robot that can track the black tape. Prize for the winner is 100 US$, with a bit condition that the winner must pay for a big party at Soi Jinda`s Somtum (Papaya Salad) shop. And one of the competitor is me. I thought the rule should be conceived roughly by students and technically by me. The picture on that day will put here soon...

Using the circuit in Fig 1, a 68HC11 µP`s stop instruction can put the µP`s external RC-oscillator clock, as well as the µP itself, into a low-power mode. On receiving an interrupt, the µP will exit the stop condition and enable the RC clock. The RC clock, being a low-Q circuit, will start up immediately. Crystal oscillators, on the other hand, can waste precious milliseconds coming up to speed and stabilizing...

Figure 2 shows a block diagram for this sine-wave generator. You can easily analyze the generator`s behavior by writing state equations in the z domain. You can also write equations in the s domain. The location of the two poles on the right-hand side reveals the generator`s oscillatory nature. The inverse Laplace transformation is simple and results in a sine-wave statement...

This algorithm uses steps in the form of n/m, where n is an integer multiplier that is not a power of 2 and m is an integer that is a number with a power of 2. Making n and m relatively independent allows you to accurately set the number of samples in one cycle. When n is larger than 255, multiplying by n using 8-bit is time consuming. This algorithm allows n to be as high as 215 and the results to be as high as 231. Division by m is easy and fast because you simply left shift the register value. The overall operating principle is to keep these values as integers to avoid using floating-point arithmetic. The resultant assembler routine is simple and fast...

The cross compiler works on any host supported by GNU tools (Solaris, GNU/Linux, FreeBSD, HP/UX, MacOS X, Windows,...)...

A simple schematic for 68HC11 or 68HC811 in Bootstrap-Mode. MODA and MODB = 0 Volt. The RS232-circuit has a automatic RESET-circuit. My assembler ASY.EXE send a BREAK-Signal with 110...

other circuits:decode, eprom ram and LCD...