How does computer chip know what a 0 and a 1 is at base level? [closed]

Question

I know there are some questions answered like this, and I have read them. I still have the same question though.

So from my understanding is that machine code is basically 0's and 1's. There are many switches that basically get turned on and off by when electricity is running through, its on (or is 1) and when no electricity it is off (or is 0).

We upload machine code so that the metal or what ever the chip on the board is comprised off, understands this and 0's and 1's. My question is how does this chip once it is built know to even recognize that we're saying 0's and 1's? How does the chip even know what a 0 or 1 is? How does it know that when switch is on to be assigning 1 to it and vise versa?

I know I cant just take a piece of metal(or what ever the chip is made of) and upload machine code it thinking that it will understand that I am trying to tell it that when switch is on to be assigned 1. How does this work?

This is one site I looked at:

How does a computer recognize 0s and 1s?

The problem is when the explanation gets to "The transistor can be turned on to enable access to the capacitor, either to charge it up and store a 1". So basically electricity goes through and the transistor is on and is charged and then stores a 1. But how does it know what a 1 is? How does it know how to interpret that 1 is associated with electricity charging the capacitor up?

As you can see, these are the questions I have. Any help would be great.

Answer 1

The core of basic computer is comprised of "binary" elements, or flip-flops. Or FF for short. The element has two states, "flip-left", and "flip-right". When the FF flops, "electricity flows" from one side to another in a fast, avalanche-like process, one side assumes high potential (voltage), the other assumes "low" voltage. Either side of FF can be considered as "right output", and all FFs are following this arbitrary convention.

As result, an information gets represented as "low voltage", and "high voltage", both somewhere in between the ground and supplying voltage. It is important to note that these two levels are fairly distinct, they don't have a continuous "analogish" spread of values. That determines the fundamental difference between analog and digital electronics. And the FF can stay in this state as long as the supply voltage is there, unless a special kick is applied so the FF can flip. These "storage elements" can be implemented in several different ways, but the principle is the same - their output assumes either a distinctive "high" level, or "low", with a noticeable gap between these two levels.

Once the levels are defined and distinct, there are elements that can discriminate between these two levels, just like a normal comparator. If a signal is above some threshold between "low" and "high", the result is amplified to "strong high". This would be a simple logical buffer. One can say that the output has "assigned" high level, or "1". Since the power supply usually is limited to certain level, 1.8V, 3.3V, or older 5V, the actual output voltage doesn't go too far, and stays within the same voltage "bin" as in the original flip-flop. So we have a consistency in voltage levels representing "low" and "high", or "0s" and "1s".

If the output gets amplified in opposite direction, it will be called "inverter". The next in complexity is a "gate" that receives two input signals, so a certain combination of them results in "strong output". Look up NOR gate as a fundamental example.

So, a computer logic "knows" which is "0" and which is "1" by sensing the difference between two levels (say, with "buffers" as described above), and flipping other internal FFs into corresponding states if needed/instructed. The actual FFs are a bit more complicated than the one shown at the beginning of Wikipedia article, scroll down to more useful FFs called D-flops. They have "reset" signal allowing to put every FF into (known) initial state, and have "enable" inputs that allow to distribute/latch common signals with discretion.

The rest of a computer is simple - FFs are grouped into registers that are wired to buses of buffers, some functions (a bit more complex than NOR) are designed, clock is ticking, and when instruction codes are fetched from memory (similar kind of flip-flop arrays), sequences of logic operations lead to desired results.

Does this explanation address your concern?

Answer 2

It doesn't "know" anything, it just does what it does. An "on" transistor conducts, an "off" transistor doesn't. We build patterns out of the electrical components, in such a way that a certain pattern of high and low voltages here results in a different pattern of high and low voltages there a moment later. We call the low voltages 0 and the high voltages 1, but the components don't care what we call them.

We choose a representation of numbers as 0s and 1s, and then we build a circuit so that if we put the representation of a number A here and the representation of another number B here, then the representation of A+B comes out there, and we say that the component is doing addition, but all the electrons know is that they're following a potential gradient.

We hook things up so that when the user presses a button with the picture "7" on it, a collection of wires get high and low voltages forced on them in the pattern that we decided corresponds to the number 7. We hook other things up so that the voltages on another collection of wires light and extinguish small lamps in just the right pattern to make a picture of the number those wires represent. Now we've got ourselves... well, a calculator really, but we're on our way to a computer.