So in this lecture, I want to start talking about LCD.
Now, LCD or used to display all type of data.
So instead of through your print end, we could be using an altered in order to print the status of
our machine, the status of our algorithm.
We could use it as a visual interface for the user.
It's just a screen and it can rise up to 32 characters.
So it has an upper line and a lower line and every line can fit 16 characters.
Now, this is not a lot, but it's a great start in order to understand this topic.
So the first thing I want to do is I want to break down the terminal.
So this is the terminal right here.
And I just want to explain to you what each of these do.
I don't want to just give you a diagram and tell you just why it's like this and why the code like this.
And you should have it magically working.
Well, LCD is actually a state machine.
We have studied that in VDL.
We studied how we can create small architectures.
Actually, this LCD is just a small architecture that contains resistors.
It contains small memories and it contained display boards.
So we can actually design a whole controller and be able to control this LCD in Adreno.
It's way simpler than that.
In order.
We know we have a ready made library that can do all the functions for us, but then we can write everything
from scratch.
Now I'm going to focus on the only part on the original part.
And I'm just I'm just going to explain the terminal for you.
It's a good thing that I give you a detailed background, because a lot of the terms I'm going to be
using right now are actually from the virtual backgrounds we have talked about.
So the first two obvious as and they are nothing but the power supply for this LTT.
Next we have a V zero, which we can which we can connect a potential meter to it.
And by rotating it, we can control the backlight of this LCD.
There is a backlight in every TV or LCD that can be controlled.
It's like controlling the brightness on your TV.
Next, we have a N.K. and they are used in order to light up the LEDs.
There is a backlight and there is a backlight is just like a plain light, the LSD of the characters
you are seeing.
So you need to power the characters of LSD individually and separately from the backlight.
They are two different things.
And actually I'm going to show you a simulation.
What's the difference if you disconnect AFIK or if you disconnect with, you know, the register is
actually to choose if you want to use a data register or an instruction register, no address is only
one bit.
Right, so it can take a value of zero or one.
So if you connect it to zero, you are using data register.
If you are connected to one, let's say you are using an instructional register.
OK, so now the data register of the data, you are going to write to your LCD and actually imagine
that you have a register and it's input of the data between zero and seven.
This is the input.
I was registered here.
It could be a democracy, SELEK, it could be a Multiplex's select in order to choose between two registers.
OK, so let's say you choose the data register.
You feed the data from all of this spend.
Let's say you choose an instruction register.
You feed also the instructions using the Spetz.
OK, so this register can play in two modes and the data will feed to it is through these bins right
here.
OK, so instructions could be something like Move the Groser.
It could be like move the character.
It could be like move the closer one or two or three characters or maybe move to a new line, stuff
like that.
Those are the instructions.
The data resistor is the data you're going to display on your LCD.
Next we have.
Right, right.
Or W.
The LCD has Dumont's either.
You can write data to it and display it second mode, which is rarely used and unusual and which is
rarely used, and we use it in order to read data from LCD.
So you wrote stuff through LCG and you want to read it using code, not visual.
L.E. not your naked eye, not your visual eye.
Then you would simply just go to the read mode and you would with all the characters that are displayed
on your LCD.
So we usually fix this to write mode so that we can only write stuff to our LCD and just display read
mode is not really that common.
Next is the enable.
This is like do you remember the flip flop we've talked about?
Well, it has a right in order to write the data or fix the data inside the register.
So imagine that these are the data on the resistor input or the different input.
And this enables here is actually the enabled pen in order to latch the data that is on this bus right
here.
OK, next, we have this zero to the seven, which are the data, as I have been saying for a while
now.
Now, actually, we will be using only the four up to the seven and we will ignore the zero up to the
three.
And you might ask, why would we do that?
Well, LCG has to move forward and now the character is actually snakebit.
So it would make sense to use that.
You use all the lines right here.
However, we don't like why do we want to minimize wires in a lot of time?
So we canceled this for and we write for bits by forwards to those before up to the seven we write them.
So if you have a character which is consist of eight bits, usually all characters are actually eight
bits.
You write the first four bits in the first cycle and the second forwards in the second cycle.
OK, this is the mode we are going to use.
And as I said, the library in between is going to take care of all of that.
You don't have to worry about it now.
These will stay empty.
Now, it is true that eight bits is faster, but as I said, we compromise it with with the need that
we do not want to use a lot of wires.
So this is the introduction to this LCD.
And as I've told you, it's just like writing code in FPGA.
And I'm telling you, this LCD is very similar to what we have learned.
And it is a statement.
There is a state machine, there are registers, there are instructions to do stuff.
This is the background of all of these small devices.
This is why it was a very good idea that I introduced you first to veejays at the so that you can understand
what's going on behind the scene.
Now, the next lecture, we're going to start applications on this LCD.