MCU Circuits

The microprocessor circuit using a power linear regulator

The microprocessor uses a linear regulator power circuit constructed as shown below, use two MAX666 simply. CPU and A / D converter power supply using A2, RAM and real-time clock power supply with A1. MAX666 output voltage Vo by the VSET (6 feet) .
MCU power supply wiring portion

High-precision voltage regulator, isolation transformer with the correct wiring and low-pass filter, to further improve the electrical noise immunity source portion. The wiring in Figure 20-48 and 20-49 as shown in FIG. Figure, chokes (Li, Lz) choose an inner .
High Quality Valve Amplifier

In recent years more and more, have a tendency ket demanded higher reimbursement structures with lights and music lovers in general and manufacturers of tube amplifiers. The reason, in their view is that the sound of tubes is more sweet, how rich and incomparably cleaner, On the other hand, however, the entire structure is much more massive than transistor amplifiers, considerably more expensive, while the operation voltages are very high that... .
Trimming the Internal Clock Generator on the 68HC908KX8 Microcontroller

One of the nicest features of the 8-bit KX8 microcontroller (manufactured by Freescale Semiconductor) is that it includes an internal clock generator (ICG). This allows the chip to run without the trouble and expense of an external crystal or canned oscillator. .
Bugdozer

Bugdozer is an autonomous mini-Sumo robot. Her main board consists of a MC68HC908GP32 microcontroller along with input/output support chips, a voltage regulator, a crystal oscillator, and the usual assortment of resistors, capacitors, and switches. All chips are socket mounted. I`m not experienced at soldering, so soldering the sockets avoided damage that could have resulted from soldering the chips directly. Also, if a chip becomes damaged in... .
Jet

The microcontroller is able to make about 7000 complete line-following decisions per second, which is almost 7 decisions per millimeter when the robot is going full speed. By upping the clock, unrolling loops, and removing my wireless debugging and extraneous code, I could increase the number of decisions per second. .
5x7 DISPLAY

The project consists of 35 LEDs arranged as a 5x7 matrix. This may not seem very impressive but you can display all sorts of effects and treat it like a "window on a large video screen." The project comes with a series of test programs to test the operation of the screen and also the surrounding components. Then we come to the experiments. They start with a simple routine to illuminate a single LED and progress to flashing a LED, running a...
LED Chaser

This was my first sucessful project with a PIC chip. I used a 16F84 with a 10MHz resonator with built in caps. Click here to view the source code to this project. The code is written in Hi-Tech C. Click here to download the source code to this project. File has a ".c" extension. .
JavaBot1

The JavaBot1 is a small line following robot designed to follow a black line drawn on a dry erase board. It is designed to follow very tight curves. The software still has lot`s of room for improvement but works well as is. The JavaBot1 uses 2 Cirrus CS-70 servos that have been modified for full rotation and have had their controller boards removed to convert them from servos to gear motors. Servos are a common motive power for small robots... .
Hidden Radio Transmitter Controller

PicCon is a PIC microcontroller based radio controller designed for hidden transmitter hunting. When combined with a radio transmitter, it will produce tone sequences and Morse code messages at user-programmed times. It is completely field programmable via DTMF tones, utilizes EEPROM for all programmed options so they are remembered when power is removed, and is quite compact. .
PIXpand (beta 0.1)

This is a beta release of the PIXpand project. The PIXpand which is a device that connects to a TI calculator and enable it to store and retreive data to and from Playstation Memory cards. I am making this beta release as I do not have the time to continue with the project right now. Thus I would be grateful if people can build this device and test it to see how well it work and to check for any bugs. .
Power up a microcontroller with pre-power-down data

It is sometimes necessary to retrieve data at power-up in the same way that they were at the last power-down, so that the product wakes up in the state it had before shutdown or to retrieve some measurement. One approach is to save critical variables into EEPROM or flash memory as soon as they change. This approach is generally not a good idea, because flash is typically limited to 100,000 write cycles, and EEPROM is typically limited to 1...
Program turns PC sound card into a function generator

You can use a low-cost PC sound card as an analog-function generator by controlling the PC with the program "SoundArb." [To obtain SoundArb, download di2409setup.exe, a 1.06-Mbyte self-extracting installation program.] The program generates standard waveforms, noise, and arbitrary waveforms. The program reads arbitrary waveforms from simple ASCII text files consisting of white-space-separated numbers. You can use a program such as Mathcad to...
Rolling-code generator uses flash microcontroller

Many security-alarm systems require the use of a random number. A computer program uses this random number to create a sequence of random numbers to prevent unwanted visitors from gaining entry into a protected facility. You can use a "rolling-code generator" to produce random numbers. To implement such a generator, you would typically need a microcontroller with external memory. Instead, you can use National Semiconductor`s COP8SBR flash µC...
Routine automates pattern/sequence detection

Sequence detection is a common operation in many communication and security systems. Some good examples are HDLC-flag identification and signature analysis. As the complexity of the system increases, designing circuitry for sequence detection becomes tedious and laborious. Using the software tool in this Design Idea, you can generate HDL code in VHDL or Verilog formats for both Mealy and Moore machines for any sequence of arbitrary length.
A serial to parallel converter using the AT89C2051

The example program included with the PG2051 evaluation kit is a basic serial to parallel converter written in 8051 assembler. This is probably a good example of the uses to which an AT89C2051 can be put - it would be hard to get a serial to parallel converter much simpler than the single 20 pin IC in this circuit. The program is meant to serve as a useful example of 8051 serial routines and other programming, whether or not you actually need... .
Simple logic analyzer pushes microcontroller to its limit

A simple logic-analyzer design is compatible with all versions of Windows and pushes the PIC 18C252 chip to its speed limit to achieve a 1-MHz sampling rate (Figure 1). The circuit can examine three channels of relatively low-speed logic signals that have infrequent, or sparse, transitions. The analyzer can record only 510 transitions per run, but a run can last as long as several minutes, if necessary. Applications include monitoring the I/O...
Single processor pin controls on/off function

A recent Design Idea prompted me to offer the simpler solution that I used in a recent project (Reference 1). We needed a momentary power switch with processor supervision. This supervision would allow the processor to delay a power-down request from a press of the power switch until all routines exited properly. In addition, in periods of inactivity, the processor could shut down the product to conserve battery life. The project also required...
Speed C functions for C16x microcontrollers

The Infineon C16x Series of µCs use an internal 16-bit-register architecture. The architecture can also process byte-wide functions. The µC uses byte moves to implement library functions such as memset() or memcopy(). This process makes the library code independent of count values and address values; both may be odd or even. The disadvantage is the loss of speed because of the need to process loop counters for every byte.
Squeeze extra outputs from a pin-limited microcontroller

Many of today`s designs use low-cost microcontrollers from Freescale and Microchip, but during the last decade, device packages have resorted to ever-smaller footprints featuring as few as eight or even six pins. Although these packages minimize pc-board area, they also reduce the number of available I/O pins and pose problems for designers who need to add one more function without migrating to a device that occupies a larger package.
10 Tricks for the `508A

Most of the ideas in this chapter can be found on the pages of this website, but just in case you want to go over the capabilities of the `508A, we have brought them together. Quite often when you are programming, the first thing you will run out of is output lines. Many projects need lots of drive lines and if you need more than about 8, you should go to another micro-controller. Don`t expect an 8-pin chip to perform the impossible. .
Pocket Programmer

The Pocket Programmer is a stand alone serial programmer that can program most of the PICmicro®MCU range of microprocessors. (12C6xx, 16Cxxx, 16Fxxx, 18Cxxx) It works from a single 18VDC supply or with 2 X 9 volt batteries. Combine this with 64K of on board EEPROM which can store upto 32 HEX files and you have a truely portable programmer / patcher. .
Two gates and a microprocessor form digital PLL

You can use Microchip`s low-cost PIC16F818 microprocessor and a pair of gates to construct a digital PLL that can clean noisy digital signals over a range of 4 to 40 kHz. Featuring programmable lock range, phase differential, and loop gain, the digital-PLL engine and lock detector can extract clock and data information from noisy, short-range radio signals (Figure 1). When you construct it using a QFN-packaged microprocessor and discrete...
Use 8051`s power-down mode to the fullest

The 8051 series µCs offer idle and power-down modes, both of which you invoke by setting appropriate control bits from the code. For instance, a 5V, 12-MHz Atmel AT89C2051 consumes approximately 9 mA in active mode, 1.8 mA in idle mode, and only 12 µA in power-down mode. Although power-down savings outperform those of the idle mode by two orders of magnitude, the only way to restore the AT89C2051`s operation from a power-down state is to...
Circuit provides 4- to 20-mA loop for microcontrollers

The 4- to 20-mA current loop is ubiquitous in the world of controls in manufacturing plants. Discrete logic, microprocessors, and microcontrollers easily cover the digital portions of control schemes, such as limit switches, pushbuttons, and signal lights. Interfacing a 4- to 20-mA output to a rudimentary microcontroller can be problematic.
Circuit provides watchdog for microcontrollers

The watchdog circuit in Figure 1 uses a single NAND Schmitt-trigger IC. The circuit is more cost-effective than dedicated, commercially available watchdog ICs. The circuit generates an active-high reset signal upon power-up and remains in a low state as long as the control input receives pulses. Whenever the pulsing at the control input stops, whether the circuit is in a high or a low state, the circuit emits a reset signal.
Wisp628

Wisp628 is designed to be used as an in-circuit programmer only, hence no socket is provided for the target chip. `Why use such a limited design`, you might ask, `an ex-circuit programmer with a ZIF socket can do the same things and more!` You are partially right, but consider the way you would use and ex-circuit programmer for development: take the chip from its circuit, put it in the programmer, program it, take it from the programmer, put... .
WLoader - a 16f877 application loader

If the piclist is an any indication the 16f877 seems to be the new favorite hobby microcontroller, a position that used to be occupied by the 16f84/16c84. Compared to is older brethren the 16f877 has much more to offer at around twice the price. As for all Microchip controllers the datasheet (pdf) and the MPLAB assembler IDE are available for free. (Microchip keeps changing its website, so when these links turn out to be invalid you might have... .
An 89C2051 CPU 8 driver outputs

This document describes the HSETI PCB. This PCB is a small simple application for the Atmel AT89C2051 microprocessor - a 20 pin 8051 variant, with FLASH (reprogrammable) program memory. The board has just two chips on it, the CPU and a driver/buffer. .
Microcontroller or DSP circuit controls on/off function

In many applications, a single on/off button switches the power supply on or off. Usually, the system switches off regardless of the processing function or workload the microcontroller or DSP circuit is currently handling. The small circuit in Figure 1 is intended to make the microcontroller or DSP circuit the master over this on/off function. The circuit allows the microcontroller or DSP circuit to take ownership over the on/off function.
Microcontroller provides SRAM battery backup

To maintain content in the event of power loss, many designs that include SRAM require a dedicated device that can automatically switch from a standard power supply to battery operation. Microcontrollers seldom find use in power-switching applications. Because microcontrollers typically operate from the primary power supply, they stop execution if that supply drops, thereby making it impossible to perform the switching operation.
Microcontroller takes control of comparator

In many µC applications, a signal conditioner modifies an analog input signal from a sensor and passes it to the µC for processing. The last stage of the signal conditioner is always a device that transforms the signal level to a value acceptable for the µC`s input. Usually, it is a comparator. Often, this signal channel is open or closed for some programmable time period.