November 2012
Intermediate to advanced
496 pages
12h 2m
English
Content preview from Using LEDs, LCDs and GLCDs in Microcontroller Projects
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
9.4 PROJECT 9.4 – Wheel of Lucky Day
9.4.1 Project Description
In this project, 7 LEDs are connected to PORT C of a PIC microcontroller. In addition, a push-button switch (START) is connected to bit 7 of PORT C. The LEDs are numbered with the days of the week, as shown in Figure 9.21. When the project is started, the LEDs are turned ON and OFF very fast in a rotating manner, such that it is not possible to see which LED is ON at any time. Pressing the button stops the rotation and only the last LED, which was ON at the time, remains lit. The day corresponding to this number is your lucky day of the week.
Figure 9.21 Wheel of lucky day
9.4.2 Block Diagram
The block diagram of the project is shown in Figure 9.22.
Figure 9.22 Block diagram of the project
9.4.3 Circuit Diagram
In general, a push-button switch can be connected to microcontroller I/O pins using two methods: Active Low and Active High.
The Active Low connection is shown in Figure 9.23. When the switch is not pressed, the input pin of the microcontroller is at logic HIGH. Pressing the switch pulls down this pin to logic LOW and this change of state can be determined by the program.
Figure 9.23 Active Low switch connection
The Active High connection is shown in Figure 9.24. Here, when the switch is not connected, the ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.