Microcontroller Circuits
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Generic Digital Switches are in-circuit programmable devices made by Lattice Semiconductor that allow pin to pin routing, buffering, and inversion. Perfect for making last minute circuit changes. Don't muck around with the software provided by Lattice, do it....
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While there is a list of features that I would like to add (32k EEPROM support, line numbers to 65,535, more stack space, strings, arrays, 16 bit variables and arithmatic, possibly named variables and REM statements for starters), I have not been able to....
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This firmware is intended to run on Atmel ATmega163 (499 bytes for program memory) or AT90S8515 (298 Bytes for program memory). Communications with the terminal is via RS-232 at 9600 baud. Use 8 data bits, 1 stop bit, and no parity. The RXD pin and TXD pin....
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Atmel described a simple programmer based on the AT90S1200 (NOT the AT90S1200A) controller in their application note, AVR910 (a modification to use the AT90S2313 is also given below).The circuit is so small and simple, I was able to put two of them together....
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The Lazy Adapter is composed of a 20 pin DIP socket, a 20 pin DIP header, and 6 pin ISP header, and a small phenolic circuit board to hold them all together. The green fiberglass PCB is a Dontronics DT104 SIMSTIC(This plug is in return for a favor.) I am....
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This adaptor lets me program 8 or 20 pin DIP devices using the In-System Programmer (ISP) described in Atmel's AVR910 application note. This circuit provides power and clocks for the part to be programmed and power to the ISP circuit. When programming 8 pin....
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I had been putting off writing a driver for some 24LC64 and 24LC256 EEPROMS I was thinking about using, when I came across a temperature logger application written by Seal Ellis. The Temperature logger was posted on on www.avrfreaks.net on January 10, 2002,....
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Plug an ATtiny12 into the 8 pin socket and hold down "GO!" button. The LED will come on at the end of the programming process, which only takes a couple hundred millisecond. The fuses are now restored to their factory default states. This picture was taken....
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This technique uses digital I/O pins to multiplex analog voltages into an analog input on the microcontroller. The method is most suitable for signals that do not need to be sampled frequently and it may be extended to accommodate a large number of inputs,....
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A simple, low component count phase locked loop that locks onto and detects the amplitude of an incoming baseband 7 bit Barker code using a switched resistor demodulator that is driven directly by a microcontroller's output pins. Balanced modulators using....
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The approaches using on-chip A-to-D converters on AVR, PIC, and Cypress controllers reached sample rates of up to about 60 kHz. Not really very useful for the sort of thing I was thinking about using this for: encoded data, radio control signals, A-to-D....
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This circuit employs a synchronous demodulator to separate a 1 KHz signal from noise and measures the amplitude of the 1 kHz signals once a second at about 60 microvolts per count then sends the measurements via an RS-232 interface for further processing or....
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The DS protocol was designed to provide firmware-based bidirectional host-to-slave inter processor communications for situations in which no hardware solution is available and the host and/or the slave in incapable of tending the interface in real time. The....
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This device provides three channels of 8 bit pulse-width modulation. Output pulse duty cycle ranges from 0 to 255/256 in 255 steps. DACs may be loaded by the DS interface. DAC values may also be copied into the on-chip EERPOM and then automatically be loaded....
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Works on AVR controllers with RAM and a hardware UART. This code is easily modified to integrate with ROM applications to provide the ability to monitor and interact with ROM applications via an terminal simulation program over an RS-232 port. It can also be....
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The assembly code given here was written to see what it would take to make an AT90S1200 generate 8 channels of proper PWM. In this case, by proper, I mean with the maximum high frequency content consistent with the needed duty cycle and give clock. Take a....
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The servo driver is just simply two 4017 decade counters and lots of 0.1" headers. Only populate the A side headers; the B servo bank is optional and will require a few more header pieces. If you received 20 headers, you'll be short two of them. If you....
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The ELC presented here has some flexibility, thanks to being software-controlled, but also has its limitations: It's intended for microhydro systems that employ a single-phase synchronous alternator, working at 220-240V, 50Hz, in a power range up to 25....
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To get enough outputs from the PIC chip, a pair of 74HC164 shift registers was used. These need only two lines from the PIC (data & shift) to produce the twelve signal pulses for the servos. A single bit is shifted into the first shift register, then, after....
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The PIC16F870 keeps track of battery voltage as well as both charging and discharging currents. It also drives the 4 digit display, and switches the AC and load relays. The basic operation is as follows: While AC power is available, the battery voltage is....
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This simple AVR Programmer will allow you to painlessly transfer hex programs to most ATMEL AVR microcontrollers without sacrificing your budget and time. It is more reliable than most other simple AVR programmers available out there and can be built in very....
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This board layout was created using the SOIC version of a PIC16F627A without drawing the usual schematic first. Most of the part values are etched on the Layout. The SIP resistor packs I used are 10k ohm, some experimentation with this value may be....
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This programmer requires only a basic terminal program capable of uploading an ascii PIC HEX file. It does not matter what operating system or computer (MAC, Win98, XP, Vista, DOS, Linux, etc.) is used to talk to it. All of the software necessary for....
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The principle of operation is quite simple, a counter measures the VFO frequency, the new
reading is compared with the previously stored value and an adequate correction is applied
consequently. This process has been implemented in the past using several....
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C1 is a charge pump capacitor*. This works voltage doubler. When TxD is negative voltage, C1 is charged through D7 from GND. If TxD carries out turn-on, since it will become positive voltage, the voltage charged in C1 is raised. The created high voltage is....
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If you are developing applications for the PIC mcu, and miss debugging tools, or don't have enough I/O pins for a parallel LCD interface in your design, this serial interface can help printing debug messages and/or reduce the pin count. This version uses a....
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Using the software during flight simulation models of planes: REAL-FLIGHT, we first chose a housing of any transmitter empty direct connection potentiometers innings. However this is not good because, first races of the potentiometers are only 90 degrees,....
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The SCHAER+ programmer is a programmer for PIC18 family from a PC parallel port (LPT). It is derivated from the SCHAER programmer I used to download my projects in PIC1684. The SCHAER+ programmer should be improved to use a USB connection, without any....
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Most of the newer PIC come with the EUSART module which have the function for auto baud rate detection. The features allow a person to set the baud rate at runtime by sending the character "U" or 0x55 to the PIC. With ABDEN (auto baud rate enable) bit set....
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The use of pulse width modulation (PWM) is common for the use of controlling power to a particular electrical device. Motor speed control, LED contrast control, power supplies are some of the example usage of PWM. 18 series PIC always come with a CCP module....
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There are 4 timers in PIC18 which are timer0 to timer3. Timers are used when precise timing event need to be generated. Timers are usually used in conjunction with interrupt to keep the timing accurate. This guide will show an example of using timer0 to....
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Here is some experimental hardware and software to transmit and receive AX.25 packets.
It is essentially a PIC-E clone designed around a Atmel AT90S2313 with a few extra bells and whistles.
I had picked up a couple of MXCOM MX-614s at the TAPR display (I....