LCD circuits

The most popular LCD interface is the Hitachi 44780 based LCD controller chip which provides a fairly easy to work with interface and low power consumption. The major drawback of the interface is the perceived complexity of working with the interface. This perception has been promoted by the lack of good (i.e. well translated) and accurate datasheets and web site information. This has been largely mitigated by the availability of a new data sheet from Hitachi; (available at here and user sites (such as my own at LCD Page with accurate information and example code that can be downloaded...

The circuit in Figure 1 can control such parameters as the view angle of an LCD screen or the volume in audio applications. One of the main advantages of this design is that a microcontroller and associated software can control it. The microcontroller system can, for example, adjust itself or calibrate peripherals depending on external conditions. With some extra logic (Figure 2), the digital potentiometer can work as a stand-alone system...

There is enough of poorly constructed RS232 alike TTL level interfaces (+5volt) , this one generates it`s own +/- 10..11volts as RS232 specs. require , and is able to use very long cables like RS232 can , and protects computer as well , nice in funny environment like inside a "MP3 in car" setup...

This is a project that I started back late 2003 when I just starting to learn PIC programming. I wanted to building something that actually did somthing useful. This project is based on a PIC16F84. I actually came up with this idea and then after doing some searching I found that a few people had the same idea. But, I wanted to build my own that I could call mine, developed by me...

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

With the HC11 board you will see all the advantages of the MC68HC11. The control of any LCD, a menustructure, the saving of data in the internal EEPROM, the application of SPI and SCI and many more. You will learn these and more using this card...

Integrating analog-to-digital converters (ADCs) provide high resolution analog-to-digital conversions, with good noise rejection. These ADCs are ideal for digitizing low bandwidth signals, and are used in applications such as digital multi-meters and panel meters. They often include LCD or LED drivers and can be used stand alone without a microcontroller host. The following article explains how integrating ADCs work. Discussions include single-, dual- and multi-slope conversions...

Many high end PDAs and smart phones have adopted color LCD screens. These LCDs are usually illuminated using white LEDs as a backlight. Since white LEDs require a higher voltage than the typical battery voltage, a boost circuit is required to boost the battery voltage. Many smart phones and PDAs also include a digital camera. Many of these cameras utilize an LED flash that helps illuminate the subject in a dark environment. The schematic below shows the application circuit. In this circuit an SC-70 Dual NMOS (Fairchild FDG6303N) device is used to switch on the flash LEDs. The flash LEDs are set for a current of 83mA (as determined by the value of R6). The backlight LEDs are dimmable by either a logic PWM signal applied to the PWM input or a DC adjust voltage applied to the DC_ADJ input...

This project displays telephone numbers decoded from tones. A microphone picks up the tones, a preamplifier boosts the signals, an SSI-202 DTMF chip decodes the tones, a Basic Stamp acts as an interface to an LCD display and also provides "RS-232" serial output. If you`d like to build your own tone decoder "from scratch", read on: You might have trouble finding the SSI-202 chip, even though Radio Shack used to sell them. In the United States, the best place to buy them in small quantities is B.G. Micro, www.bgmicro.com. They have the SSI-202 chip for $2.25. If you have access to Mitel 8870 DTMF chips, you could use it in this circuit if you change the pins to match the corresponding functions. I have not done it, so I cant help you...