Logic_Circuits

?C implements Pushbutton Light Dimmers: 06/18/98 EDN-Design Ideas

10 Tricks for Interfacing to the PIC16C508:

101 AT Keyboard to ASCII Decoder using 68HC705J1MCU:

101 AT Keyboard to ASCII Decoder: The Host to Keyboard Protocol is initiated by taking the KBD data line low. However to prevent the keyboard from sending data at the same Time that you attempt to send the keyboard data, it is common to take the KBD Clock line low for more than 60us. This is more than one bit length. Then the KBD data line is taken low, while the KBD clock line is released.

12C508 Smart Lock: The base sends a data sequence (the password) which is recognized by the key. The key checks the sequence and -if it recognizes it -sends to the base another data sequence, as an answer to the password. At the Time when the base gets a correct answer (which means that the key has been introduced), the relay is put into action, and it can command a number of consumers.

15 Step Digital Power Supply:

2 Chip Digital Thermometer Delivers 0.4?C Accuracy : 07/08/02 Electronic Design - Ideas for Design / An LED digital thermometer with an operating range betw1een 0?C and 150?C, 1?C resolution, and ?0.4?C accuracy is presented in the figure. This design is based on the PIC16F872...

2 Transistors Form Bidirectional Level Translator: 11/07/96 EDN-Design Ideas / Illustrates a translation from5 to3V, but it can accommodate almost any other voltage levels, provided the logic-low levels are equal (usually0V), translation from1 to100-Volt are possible although slow.

2 Wire LCD Interface using PIC16CF84:

24 Bit RGB Video Digitizer: designed for use as the front end of a digital video processor

68HC11 Function Generator:

68HC11 Instruction halts External RC Clock: 04/27/95 EDN-Design Ideas

68HC11 Stepper Motor Control:

68HC11 Synthesizes Accurate Sine Wave: 09/02/96 EDN-Design Ideas

About PIC Microcontrollers:

AFSK 1200 Modem Based on PIC16C620:

Analog input circuit serves any microcontroller: 12/20/2001 EDN - Design Ideas / The simple ADC in Figure 1 is perfect for getting analog signals into a purely digital microcontroller. Using just five surface-mount parts, you can assemble it for less than 50 cents (1000), which is approximately half the cost of a single-chip-ADC approach in the same volume. Moreover, this design takes only one pin from the microcontroller to operate. .

Analog to Digital Conversion Notes for PIC Processor:

Array Logic Provides High Speed Multiplication: 07/18/96 EDN-Design Ideas

AT89C2051 / 4051 Driving Dot LED:

AT89C2051 / 4051 Easy Downloader:

AT89C2051 / 4051connecting Dumb Terminal:

AT89C2051 / 4051scanning 7 Segment Display & Keypad:

AT89C2051 / 4051Stepper Motor Interface:

AT89C2051 Digital Thermometer & Clock:

AT89C2051 Line Follower Robot:

AT89C2051 Night Light Saver:

AT89C2051 Real Time Controller:

AT89C2051 Serial Coms to LED Driver:

AT89C51 / 52 / 55 Easy Downloader:

Atmel 8051 Flash Based Microcontroller Programmer:

Atmel 89C Series Flash Microcontroller Programmer:

AVR microcontroller makes improved motor controller: 10/17/2002 EDN - Design Ideas / The circuit in Figure 1 provides a novel method of reading the pulse train using an Atmel (www.atmel.com) AVR processor, from a typical radio-controlled receiver, and to determine the velocity of a motor. To capture the pulse train from a typical receiver, you need an external interrupt that triggers based on a rising and a falling edge..

Basic Stamp Computer Eases Prototyping hassles: 04/09/98 EDN-Design Ideas

Build a PIC Controlled DDS VFO, 0 to 6 MHz:

Build Logic Gates using Discrete Parts:

C 52 EVB Robot Controller:

Casio QV 200 Digital Camera Cable: Lose your cable? Build it yourself and save $29. Fits many QV models.

Circuit Controls tw1o LEDs With One Microcontroller Port Pin : 04/01/02 Electronic Design - Ideas for Design / Microcontroller port pins can typically be driven either high or low, or else be put into an "input" or high-impedance state. This circuit uses the three states to drive tw1o separate LEDs with one port pin. This can be very useful when there are no...

Circuit Converts Betw1een TTL & Shifted ECL: 08/15/96 EDN-Design Ideas

Circuit forms industrial grade digital potentiometer: 09/20/2001 EDN - Design Ideas / Both ac and dc motors in modern industrial systems often receive their control from PLCs (programmable-logic controllers) in a control room safely away from the process. If an operator must manually set the motor speed while observing the proc.

Circuit provides watchdog for microcontrollers: 12/26/2002 EDN - Design Ideas / 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, th....

Circuit transmits ARINC 429 data: 07/11/2002 EDN - Design Ideas / The ARINC (Aeronautical Radio Inc) 429 specification defines the air transport industry`s hardware and protocol standards for the transfer of digital data betw1een avionics systems. Circuitry that can implement elements of the 429 spec is often an essential part of control and sensor electronics intended for the aviation environment..

Clock Divider Circuit:

Clock Doubling Circuit (500KHz) for CMOS Logic: Exclusive OR gate

Closed Caption Decoder: This is a closed-caption decoder with serial output, based on a PIC16C71, an ?lantec EL4581C sync separator, and an LM393 dual comparator (for data slicing with automatic threshold).

Combination Lock (PIC16F84):

Connecting LED to PIC Micro I/O Pins:

Connecting PIC12C508 8 to 93AA46 Serial Eprom:

Controller Provides Multiple Alarm Driver Formats: 01/15/98 EDN-Design Ideas

Correlator Works in Presence of Noise: 02/03/94 EDN-Design Ideas / Clipped-signal Correlator outperforms any resistor-capacitor clipped-signal Correlator, and the circuit has no race paths

Difference amplifier uses digital potentiometers: 05/30/2002 EDN - Design Ideas / You sometimes need to measure a small signal in the presence of a large common-mode signal. Traditional instrumentation amplifiers that use tw1o or three op amps in their internal structure find common use in these applications. The circuit in Figure 1 presents an alternative approach that is useful when low cost and low drift are important, but when you don`t need high precision..

Digisound Ring Modulator:

Digisound VCDO Parts Lists / Layout:

Digital / Standard Phone Line Tester: make sure that the line is suitable for modem use and your PCMCIA does not damage if you plug it in

Digital Automatic Gain Control (AGC):

Digital Camera Interface: (PDF) project shows how a CMOS ‘Camera On a Chip’ image sensor can be interfaced to an XSA-100 Board through an I2C bus. The pixel data is buffered in the XSA-100 SDRAM and is then uploaded through the parallel port to be displayed on a PC.

Digital Combination Lock:

Digital Compass Schematic:

Digital current source is nonvolatile: 02/07/2002 EDN - Design Ideas / Digitally programmable current sources that feature automatic trimming and retain the setting despite power-down cycles are useful in applications such as RF- and laser-communications drivers. The circuit in Figure 1, for example, is particularly suited for setting the drive current for the optical pump in widely tunable VCSELs (vertical-cavity surface-emitting lasers). .

Digital Delay Unit for Surround Sound:

Digital Echo:

Digital Filter Makes Simple Spike Eliminator: 04/10/97 EDN-Design Ideas

Digital Frequency Counter:

Digital Knobs:

Digital Mains Voltage Indicator:

Digital PC Oscilloscope:

Digital PLL Synthesis: National Semiconductor Application Notes,04-Nov-1995

Digital Position Encoder Does Away With ADC: 05/08/97 EDN-Design Ideas

Digital Pot Adjusts LCD`s Contrast: 02/04/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find circuit.

Digital Pot Corrects for System Drift: 11/10/94 EDN-Design Ideas

Digital Potentiometer Autonulls OpAmp: 10/22/98 EDN-Design Ideas

Digital Potentiometer Controls LCD Bias: 03/17/94 EDN-Design Ideas

Digital Potentiometer Controls Phase Shift: 02/15/96 EDN-Design Ideas

Digital potentiometer programs and stabilizes voltage reference: 05/30/2002 EDN - Design Ideas / The potentiometer portion of a mixed-signal, digitally programmable potentiometer adds variability to an analog circuit, and its digital controls provide programmability. You can use a digital potentiometer in tw1o ways in an analog circuit. You can use it as a tw1o-terminal variable resistance, or rheostat, or as a three-terminal resistive divider..

Digital Pressure Gauge:

Digital Quality Microphone Pre Ampl. Using the Model 425 OPAMP :

Digital signal controls sine generator: 05/15/03 EDN-Design Ideas / The circuit of Figure 1 produces an accurate, variable-frequency sine wave for use as a general-purpose reference signal. It includes an eighth-order elliptic, switched-capacitor lowpass filter, IC3, which uses a 100-kHz square-wave clock signal that microcontroller IC2 generates. (Any other convenient square-wave source is also acceptable...

Digital Signal Processor (DSP) for Radio Communications:

Digital Signals Produce Pure Sine Waves: 10/09/97 EDN-Design Ideas

Digital Speed Control for RC Car: DC motor PWM controller that takes the1ms to2ms pulse from the RC receiver and converts it into a PWM train at1Khz

Digital Step Km Counter Max.: Pedometer has a range of 9.950 meters with2-digits. Slip it in pants pocket for walking and jogging

Digital Stereo Potentiometer: in PDF format, text in Finnish

Digital Storage Oscilloscope Adapter Mk #3:

Digital Storage Oscilloscope :

Digital Switching System:

Digital Sync tip Clamping: 10/08/98 EDN-Design Idea / Digital sync-tip Clamping allows an ac-coupled ADC to digitize analog video without restoring the horizontal Timing. A new approach to video signal conditioning.

Digital Tachometer Avoids Analog Vices: 11/10/94 EDN-Design Ideas

Digital thermometer:

Digital Timer has Independent On / Off Periods: 03/28/96 EDN-Design Ideas

Digital to Analog Centronics D / a & Filter:

Digital Video Processor:

Digital Video TBC / Standards Converter: This project is a Time base corrector/standards converter. There is only a partial project description available.

Digital Volt Meter With Video Output:

Digital Volt Meter:

DIGITAL VOLTMETER: This is just a schematic view of a digital voltmeter all components and values are listed.

Digital volume control has log taper: 04/11/2002 EDN - Design Ideas / Digital potentiometers provide a compact and convenient way to attenuate audio-amplifier signals. However, most such potentiometers suffer from at least one flaw: a nonlogarithmic step increment. To avoid this problem, a user must usually step.

Digital Volume Control: based on DS1669 Digital Pot IC

Digital Water Wave/Tide/Level Meter (PIC16F876):

Digitally Adjust Regulator`s Output Using a JFET Interface : 04/29/02 Electronic Design - Ideas for Design / Often, electronic systems are guaranteed to operate with any supply voltage, within a given VCC range. Testing these circuits requires a regulated voltage supply that can be automatically incremented, from a minimum to a certain maximum....

Digitally Control Gain over a ?40 DB Range: 09/12/97 EDN-Design Ideas / digitally control an amplifiers gain over a ?40-dB range gain Resolution of1.25 dB

Digitally Controlled Phase Shift: Altering the phase response of a signal without changing its amplitude characteristics is commonly performed using an all pass filter. This circuit implementation is well suited to using digital potentiometers as the controlling element.

Exclusive Or Gate Applications:

Generate Video Signals: in real-time using a PIC16F84

High Efficiency Halogen Bike Light Dimmer: This circuit uses a PIC16F84 microcontroller with some softw1are to control20-Watt12V DC halogen lamp

High Performance FM Receiver for Audio & Digital:

Interfacing thePIC16C508:

Key reading circuit saves I/O pins: 03/06/03 EDN-Design Ideas / Some microcontroller applications usually use too many I/O pins to read keys or onboard switches; in many cases, few pins remain available for other uses. Some alternative ways to read keys yield more free pins. First, consider some ways to effect key reading. Table 1 presents a comparison of four methods with references to circuit configurations (figures 1, 2, 3, and 4)

Logic Family Voltage Translation: how to translate betw1een TTL, 74xx, CMOS, ECL, PECL, Low Voltage TTL, LVTTL, etc.

Logic offers complementary switch control: 12/06/2001 EDN - Design Ideas / The complementary-switch controller in Figure 1 uses a few inverter gates to provide drive signals for the complementary switches. Complementary-switch configurations find widespread use in synchronous-rectification circuits, charge pumps, full-bridge control circuits, and other circuits. The circuit in Figure 1 provides not only a complementary drive signal but also a deadtime delay ... .

Logic Probe:

Low Cost Digital Thermometer Uses SingleChip Microcontroller : 02/18/02 Electronic Design - Ideas for Design / In many applications, the ability to read and display temperature is either desirable or an absolute requirement. Some of these applications include temperature probes, thermostats, CPU monitors, and process-control equipment. The ...

Low Voltage Interface Circuits Translate 1.8 to 5V: 11/05/98 EDN-Design Ideas

Low Voltage Reset operates Below 2.7V: 03/26/98 EDN-Design Ideas

Make a DAC with a microcontroller`s PWM timer: 09/05/2002 EDN - Design Ideas / Many embedded-microcontroller applications require generation of analog signals. An integrated or stand-alone DAC fills the role. However, you can often use PWM signals for generating the required analog signals. You can use PWM signals to create both dc and ac analog signals. This Design Idea shows how to use a PWM timer to simultaneously create a sinusoid, a ramp, and a dc voltage..

Make noise with a PIC : 08/07/03 EDN-Design Ideas / Building a stable noise generator for audio-frequency purposes requires only a few components. The circuit in Figure 1 relies on linear-feedback shift registers and some simple softw1are. An eight-pin Microchip (www.microchip.com) PIC12C508 controller (IC2) with a short program generates pseudorandom noise at its output pin, GP0....

Methods Link ECL & PECL: 03/02/95 EDN-Design Ideas

Microcontroller becomes multifunctional: 10/25/2001 EDN - Design Ideas / A microcontroller, by default, can execute only one program at a time. What do you do if, in a given project, you need to perform more than one operation at a time? Add more microcontrollers to the design? In certain cases it`s unnecessary. Consider a real-life situation (Figure 1). The microcontroller constantly generates on its Pulse output pin a sequence of pulses with 25-msec duration... .

Microcontroller Emulates Numerically Controlled Oscillator : 02/21/02 EDN-Design Ideas / Microcontrollers commonly add intelligence or digital functions to products, but they can also provide a variety of analog signals. This circuits uses an18-pin PIC16C54 microcontroller, combined with an inexpensive, 8-bit DAC and a simple lowpass filter.

Microcontroller Interface for 5KWatt Microwave oven:

Microcontroller Makes Effective Frequency Counter: 11/23/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Microcontroller MultiChannel Light Dimmer: The project is a microprocessor-controlled multiple channel lighting dimmer, that could be used in theatrical and other applications. The device will accept input from a wide range of interfaces: RS232 input, DMX512 (theatrical lighting standard) or RS485, or a Musical Instrument Digital Interface (MIDI). The device will control a number of lamps by using some form of AC power control. The firmware in the microcontroller will handle all functions, from decoding the protocol on either of the input interfaces through to Timing the firing of power triacs for the output.

Microcontroller Watches, Controls AC Power: 06/22/95 EDN-Design Ideas -- circuit allows an isolated microcontroller to both sense and control ac power to an externally plugged-in device

Microprocessor RS232 Reset:

MiniLOGGER V1.0:

Mk1 PC Based EPROM Programmer:

Mk2 PC Based EPROM Programmer:

Multi Chip Programmer:

Multimedia Electronic Crib: microcontroller based light controller which generates sequence of day-night with light fading, optional serial control interface, based on 87C51

One Microcontroller Serves Multiple External Interrupts: 02/01/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Pedometer:

PIC 5x7 Display:

PIC Based Keyboard Emulator:

PIC Based Motor Controller:

PIC Based Web Server:

PIC Controlled DDS VFO, 0 to 6 MHz:

PIC Logic Probe With Pulser:

PIC Programmer: to download programs into PIC microprocessors.

PIC Tetris Game:

PIC12C508 Night Light Saver:

PIC16C84 VT 52 Emulator for Linux: