Getting started with CPLDs – Part 8

cpldjIn this article, we’re going to re-use the hardware from the 4-bit binary adder but convert it into a 4-bit binary subtractor instead.

It’s a very simple modification to the schematic design. We simply invert the B inputs and leave the A inputs as they are. Instead of adding A and B, this configuration will subtract B from A.

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Getting Started with CPLDs – Part 7

cpldjIn part 6, we built a 1-bit full adder. In this part we’re going to expand upon that and build a complete 4-bit binary adder. I have made the assumption that you already know about the binary number system but in case you don’t, have a look here and do some searching to learn about it.

Back? Great, let’s get on with it. Grab your CPLD development board, a breadboard and the usual handful of LED, switches and resistors. We will need switches for this guide instead of buttons.

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