LCD and 7segment circuits
LCD : liquid crystal display The 16*2 character LCD screen component has 14 or 16 pins. The pin connection table is: Pin #1 is connected to ground Pin #2 is connected to power supply through a resistor Pin #3 is usually to a potentiometer and determines the contrast of the characters Pins #4, #5 and #6 are the control inputs Pins #7 to #14 are the data inputs Pins #15 and #16 are the back-light control and are usually not connected In order to control or write to the LCD screen component a micro-controller has to be used. The data inputs of the LCD can be wired to the micro-controller with an 8 bit bus or a 4 bit bus. Example of wiring an LCD screen to a Microchip pic18f452 in an 8 bit bus: Tutorials teaching code writing for LCD: http://www.piclist.com/techref/io/lcd/pic.htm www.8051projects.net/microcontroller-tutorials/ Datasheets of LCD: http://www.datasheetcatalog.org/datasheet/vishay/016m002b.pdf http://www.sparkfun.com/datasheets/LCD/HD44780.pdf 7 segment a form of electronic display device for displaying decimal numerals by using arrays of light-emitting diodes (LEDs). Meaning displaying 0-F . There are two types of LED 7-segment displays: common cathode (CC) and common anode (CA). The difference between the two displays is the common cathode has all the cathodes of the 7-segments connected directly together .For the use of this seven segment the common cathode connection must be grounded and power must be applied to appropriate segment in order to illuminate that segment. And the common anode has all the anodes of the 7-segments connected together. Then by applying a ground to a particular segment connection (a-g), the appropriate segment will light up. One method of displaying characters is directly with a micro-controller: Second method involves a converter from BCD inscription to 7-segment: The truth table for the BCD to 7-segment converter is: back to basic electronic circuits for robotics page |
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