Reverse Engineering

 

There are flip flops but there is also something called a flip-flop

I came in today with a completed circuit built using logic gates. The students were tasked to figure out what it does and how it does it! In this way they were put in the roles of reverse engineers! They had to test the inputs, observe the results, look at the chip on the board, match it up to a data sheet to know the pins and gates, draw out the logic diagram and solve the circuit.

The circuit in question was what is know as a Flip-Flop, or SR latch. This circuit is the simplest form of computer memory, capable of storing a single Bit of data even once the original high or low signal is removed. It is a little trickier than previous logic diagrams because the circuit exhibits a feedback loop. This loop is what enables a Bit of data to be stored as an electrical signal. 

 
 
 
This is the first in a series of videos about latches and flip-flops. These bi-stable combinations of logic gates form the basis of computer memory, counters, shift registers, and more. In particular, this video covers the set-reset latch, otherwise known as the SR latch.