How multiplexing works with 7-segments Display in Assembly Language скачать в хорошем качестве

How multiplexing works with 7-segments Display in Assembly Language

Working with Seven Segment LED Displays Structure and operation of a seven segment LED display This is s a quick introduction to the basics of using seven segment LED displays with microcontrollers. Be sure to refer to the manufacturer's data sheets for more information about the devices mentioned in this tutorial. Figure 1 shows a seven segment LED display. As indicated by the diode equivalent circuit on the left, each segment is an individual LED. This is a Common Cathode (CC) display. All of the cathodes (or negative terminals) of the segment LEDs are connected together. In this video , we discussed about interfacing a seven segment LED display to a PIC microcontroller. The seven segments were driven individually through separate I/O pins of the microcontroller. If we do just like that then for 4 seven segment LED displays, 28 I/O pins will be required, which is quite a bit of resources and is not affordable by mid-range PIC microcontrollers. That’s why a multiplexing technique is used for driving multiple seven segment displays. This tutorial shows how to multiplex 4 common anode type seven segment LED displays with a PIC16F628A microcontroller. The theory behind the multiplexing technique is simple. All the similar segments of multiple LED displays are connected together and driven through a single I/O pin. In the circuit the seven segments are connected to PORT0 through current limiting resistors Rs. A particular segment is active when the corresponding PORT2 pin is low. However, it will not glow until it’s anode is connected to Vcc. You can see the anodes of the four LED displays are not directly connected to Vcc. Instead, 4 NPN transistors are used as switches to connect or disconnect the anode terminals from Vcc. When the base of the NPN transistor is high, the transistor conducts and corresponding digit’s common anode is connected to Vcc. Therefore, the transistor selects which displays is active. The conduction of the transistors are controlled through pins of PORT2. Suppose, if we want to display 7 in the units digit place, then segments a, b, and c should be turned on firs and then PORT 0 should be pulled low so that only units digit display will be active. In order to display all 4 digits, each seven-segment display is activated sequentially using an appropriate refresh frequency so that it will appear that all the them are turned on at the same time. Follow us on Facebook   / star-technology-5g-114217917006898   Follow us on Twitter   / startechnolog18   Follow us on Blogger https://www.blogger.com/blog/posts/34... Follow us on Tumblr   / startechnology5g   Follow us on Pinterest   / startechnology5g   Follow us on Linkedin   / star-technology-5g-0779661b2   Follow us on Reddit   / startechnology5g   Follow us on Mix https://mix.com/startechnology5g Follow us on Skyrock https://skyrock.com/m/account/confirm... #microcontroller #electricalengineering #assemblylanguage