How do computers work? CPU, ROM, RAM, address bus, data bus, control bus, address decoding.

Summary

This script delves into the fundamentals of computing, focusing on the CPU and memory interaction. It explains how CPUs execute programs, the role of ROM and RAM, and the significance of address decoding. The video illustrates how data is read and written between the CPU and memory chips, the use of address, control, and data buses, and the importance of decoding in a computer system. It also touches on the evolution of computer buses and the principles behind input/output operations, concluding with a simple example of controlling an LED, showcasing the practical application of these concepts.

Takeaways

• 💡 The CPU is the heart of any computing device, executing programs and consuming data from external memory.
• 🔍 The CPU reads programs byte by byte, similar to reading a book word by word, with each byte having a value from 0 to 255.
• 📚 Computer memory is organized as an array of bytes, each with a unique address starting from zero.
• 🔢 Memory types include ROM, which contains pre-programmed code, and RAM, which holds temporary data and is erased when power is interrupted.
• 🛤️ The address bus is a set of wires that encode memory cell addresses in binary for the CPU to communicate with memory chips.
• 🔁 The control bus, with signals like read (Rd) and write (WR), determines the operation the CPU intends to perform with memory.
• 🔄 The data bus is bi-directional, transferring data between the CPU and memory or peripherals, with its size impacting system performance.
• 🔑 Address decoding is crucial for memory chips to know which device the CPU is addressing, preventing data bus collisions.
• 📉 The size of the address space is determined by the number of address bus lines and is tied to the CPU model.
• 🔠 Hexadecimal is used in computing for its efficiency in representing binary numbers, simplifying memory address and data representation.
• 🔩 Real computers use a more complex decoding mechanism to allow for multiple memory and input/output devices to be addressed individually.

Q & A

What is the primary function of a CPU in a computing device?

The primary function of a CPU in a computing device is to execute programs or code. This involves reading and processing data from external memory as long as power is applied.

How is computer memory organized?

Computer memory is organized as an array of integer numbers called bytes, with each byte capable of taking a value from 0 to 255.

What is the difference between ROM and RAM in a computer system?

ROM (Read-Only Memory) typically contains pre-programmed code for the CPU to execute, while RAM (Random Access Memory) mostly contains temporary data that can be both read and written to by the CPU. ROM retains data even when the power is off, whereas RAM is erased when power is interrupted.

What is the purpose of the address bus in a computer system?

The address bus is used by the CPU to communicate the memory cell address it wants to read from or write to. It's a set of electrical wires that encode memory cell addresses using binary system (ones and zeros).

Why are read and write signals in a computer system active low?

Read and write signals are active low due to power consumption considerations. This means that the CPU pulls the read line low to perform a read operation and the write line low to perform a write operation.

What is the significance of the data bus in a computer?

The data bus is crucial for transferring data between the CPU and memory chips. It's bi-directional and its size directly affects the performance of the system. The data bus carries data in binary format, with the size of the data bus determining the size of a single memory cell.

How does address decoding help in differentiating between different memory chips in a computer system?

Address decoding uses logic gates to output logic 0 when a certain pattern of ones and zeros is present on its inputs. This mechanism allows the CPU to differentiate between memory chips by assigning them specific address ranges.

What is the role of the control bus in a computer system?

The control bus is a signaling system that includes lines like read (Rd) and write (WR) to indicate the operation the CPU intends to perform. It helps in managing the communication between the CPU and other devices on the computer motherboard.

Why is the hexadecimal numbering system used in computers and programming?

The hexadecimal numbering system is used because it simplifies the representation of binary numbers. It replaces every combination of four binary digits with one hexadecimal digit, making it easier to work with memory addresses and data.

How does the CPU interact with input/output devices in a computer system?

The CPU interacts with input/output devices using read and write operations, which are decoded into a separate address space. This is facilitated by additional signals on the control bus, such as input/output request (IOWR) and memory request (MEMR).

Outlines

00:00

🖥️ CPU and Memory Basics

This paragraph introduces the central processing unit (CPU) as the core of any computing device, responsible for executing programs. It explains how the CPU reads programs byte by byte from memory, similar to reading a book. The concept of memory cells, addresses, and the types of memory (ROM and RAM) are discussed, highlighting the permanence of ROM and the volatility of RAM. The BIOS chip and its role in system startup are also mentioned, along with a simple example of how a CPU and ROM chip interact using an address bus to read program code.

05:00

🔄 Understanding Memory Operations

The second paragraph delves into the mechanics of memory operations, focusing on the unidirectional address bus and the control bus that signals read (Rd) and write (WR) operations. It discusses the mutual exclusivity of read and write signals and the rationale behind active low signals for power consumption. The paragraph also introduces the data bus, which is bi-directional and central to the system's performance, with an example of how the CPU reads a byte of data from ROM and interprets it as a machine code instruction.

10:03

📚 Address Decoding and Memory Mapping

This section explains the concept of address decoding, which is essential for distinguishing between different memory devices in a computer system. It describes how the address space is divided into fixed ranges for ROM and RAM, using the CPU's address lines to determine the maximum addressable space. The paragraph also covers the hexadecimal numbering system as a more convenient way to represent binary numbers and how memory chips are activated based on address ranges, with examples of how ROM and RAM are assigned to different parts of the address space.

15:04

🔌 Chip Select and Memory Interaction

The fourth paragraph discusses the chip select (CS) signal and its role in activating memory chips based on address ranges. It explains how the least significant bit (LSB) and most significant bit (MSB) of an address determine which memory chip is active. The paragraph also describes the use of control lines like output enable (OE) for ROM and the right signal for RAM, and how these are used in conjunction with address decoding to prevent data bus collisions during read or write operations.

20:06

🔄 Memory Access and I/O Operations

This section describes the process of memory access and input/output (I/O) operations in a computer system. It explains how the CPU interacts with memory and I/O devices through a contiguous address space, with each device responding based on its assigned address range. The paragraph also introduces the concept of memory request and input/output request signals on the control bus to differentiate between memory and I/O operations, using an example of how to add an output port to control an LED.

25:07

🔌 Expansion and Decoding in Computer Systems

The final paragraph explores the principles of expansion and decoding in computer systems, comparing the traditional parallel connection and individual addressing of peripheral devices with modern approaches used in PCI Express buses. It discusses how expansion cards and slots operate, the role of decoder chips, and the shift towards independent communication lines for each expansion board in contemporary systems. The paragraph concludes with an invitation for viewers to engage with the content and the channel.

Keywords

💡CPU (Central Processing Unit)

The CPU is the primary component of a computer that performs the execution of a program's instructions. It is often referred to as the 'brain' of the computer. In the context of the video, the CPU's role is to read and execute code from memory, emphasizing its importance in the fundamental operation of any computing device.

💡Program Execution

Program execution refers to the process by which a computer runs software instructions. The video script explains that the CPU reads programs byte by byte, executing them as long as power is applied, akin to reading a book word by word.

💡Memory Cell

A memory cell is the basic unit of computer memory that stores a single piece of data, which can range from 0 to 255. The script uses the analogy of a memory cell to a book where each page is a cell, highlighting how the CPU accesses these cells through unique addresses.

💡Address

In computing, an address is a unique identifier for a memory cell. The script explains that all cells are numbered starting from zero, and this numbering system is crucial for the CPU to locate and access specific memory cells.

💡ROM (Read-Only Memory)

ROM is a type of memory that contains pre-programmed code intended for the CPU to execute. The video mentions ROM as a memory type that is typically used to store firmware, a proprietary software that runs on specific hardware.

💡RAM (Random Access Memory)

RAM is a type of memory that is used to store temporary data and can be both read and written to by the CPU. The script contrasts RAM with ROM, noting that RAM is erased when power is interrupted, unlike ROM which retains data.

💡Address Bus

The address bus is a communication system that carries the memory cell address information from the CPU to memory or input/output devices. The video script describes how the CPU uses the address bus to specify the address of the memory cell it wants to read from or write to.

💡Control Bus

The control bus is a set of signals used to manage the operations between the CPU and other devices. The script explains that the control bus includes signals like read (Rd) and write (WR), which indicate the CPU's intention to read from or write to a memory cell.

💡Data Bus

The data bus is a bi-directional communication system that carries actual data between the CPU and memory or input/output devices. The video script uses the data bus to illustrate how data, such as the contents of a memory cell, is transferred during read and write operations.

💡Firmware

Firmware is a type of software embedded in a hardware device for controlling its operation. The video script mentions firmware as the program stored in ROM that the CPU reads and executes when power is applied, emphasizing its role in the boot-up process of a system.

💡Address Decoding

Address decoding is the process of determining which device should respond to a CPU's request based on the address provided. The script explains that this is achieved through logic gates that activate memory chips only when the correct address pattern is present, preventing conflicts on the data bus.

💡Hexadecimal

Hexadecimal is a base-16 number system used in computing to simplify the representation of binary numbers. The video script introduces hexadecimal as a way to represent memory addresses and data, making it easier for humans to read and understand binary values.

💡I/O Ports (Input/Output Ports)

I/O Ports are interfaces on a computer that allow for communication with external devices such as keyboards and mice. The video script discusses how the CPU uses read and write operations on these ports, which are decoded into a separate address space, to interact with the user.

Highlights

The CPU is the heart of any computing device, executing programs and code.

CPUs read programs byte by byte, similar to reading a book word by word.

Computer memory is organized as an array of bytes, each with a value from 0 to 255.

Memory cells are numbered starting from zero, with the ordinal number called the address.

There are two types of memory: read-only memory (ROM) and random access memory (RAM).

ROM contains pre-programmed code, while RAM mostly contains temporary data.

ROM retains data even when the computer is off, unlike RAM which is erased when power is interrupted.

BIOS is a small program that executes every time you boot up your system.

The address bus is a communication system that uses binary to encode memory cell addresses.

The control bus uses signals like read (Rd) and write (WR) to indicate the operation intended by the CPU.

The data bus is bi-directional and carries data between the CPU and memory chips.

Address decoding is a mechanism used to determine which device the CPU is addressing.

The address space is divided into ranges, with each memory device assigned a specific address range.

Hexadecimal numbering is used in computers and programming for easier representation of binary numbers.

The CPU accesses memory cells by address and receives data based on the address range decoded by memory ICs.

Real computers use more complex decoding mechanisms to allow multiple memory and input/output devices to be addressed.

Input/output ports allow the CPU to interact with peripheral devices through read and write operations.

The video demonstrates how to add a simple one-bit output port to control an LED, showcasing the principles of computer engineering.

Transcripts

the heart of absolutely any Computing

device be it personal computer

smartphone or a programmable calculator

is the center processor or CPU

the cpu's main job is to execute

programs or code

what this actually means is that as soon

as power is applied the processor hungry

for executable code starts consuming

data from external memory

just like a person who reads a book word

by word the processor reads the program

by it by bite as long as power is

applied to the Circuit the CPU cannot

stop and program execution continues

forever

and just like a book is made up of

sequence of letters words and sentences

computer memory is organized as array of

integer numbers called bytes and each

byte can take a value from 0 to 255.

in order for the CPU to know which

memory cell exactly IT addresses all

cells are numbered starting from zero

the ordinal number of a cell is called

address

for example memory cell number 300 has

an address of 299

that's because cell numbers start from

zero

computer memory is very similar to a

sheet of paper you can write something

in it that can be read later there are

basically two types of memory read-only

and random access

read-only memory or ROM usually contains

pre-programmed code which is intended

for the CPU to execute while random

access memory or ROM mostly contains

temporary data either generated by the

CPU itself or loaded by the CPU from

external media during program execution

as the name suggests read-only memory

can only be read by the CPU while Random

Access Memory can be both read and

written to

this means that ROM retains data even if

you turn off your computer while Ram is

erased every time Powers interrupted

dim sticks installed in your PC or

laptop is RAM

and bios chip is wrong

bios is a small program that is executed

every time you boot up your system

let's now take a glance at how it works

imagine a very simple Computing device

consisting of a CPU and a ROM chip

the ROM chip contains a program called

firmware

the name firmware suggests that it's a

proprietary piece of software that can

only run on a certain device

as the power is applied the CPU

immediately addresses the ROM chip in an

effort to read program code that it

could execute

obviously for that to happen it needs to

read data from a number of memory cells

so each cell is read by specifying its

address which like was mentioned above

is its unique ordinal number

for the CPU to be able to tell the ROM

chip the address of the cell it wants to

read all computers have a communication

system called address bus

by Design it's basically a set of

regular electrical wires that use binary

system that's ones and zeros to encode

memory cell address

this method in fact is always used by

computers to communicate numbers between

devices

imagine that the CPU wants to read cell

whose address is 44 206.

this is just a random sample number it

doesn't mean anything

let us now open Windows calculator and

convert it to binary

the result is this binary number

note that it has 16 bits that's binary

digits

so exactly these ones and zeros the CPU

will put up on the address bus to reach

cell number 44 206.

yep it's that simple

please note and that is very important

the least significant bit LSB of the

address which is zero in our case will

be put up at address line a0

well the most significant bit MSB will

be at line a15

address numbering like everything in

programming also starts at zero

because the address is always sent from

the CPU to external devices and never in

the reverse Direction the address bus is

unidirectional which means the CPU

address lines are outputs and the ROM

chips address pins are inputs

so all devices on a computer motherboard

are connected to the address bus in

parallel

but it's obvious that computer memory

supports two types of communication

reading and writing

how would the memory chip know which

operation exactly the CPU intends to

perform

for that computers use a signaling

system called the control bus

it also consists of regular wires and

its two most important lines are read

and write designated as Rd and WR

please note both the read and write

signals are active low meaning if the

CPU intends to perform a read operation

it pulls the read line low

if it wants to write data it pulls the

right line low

these two signals are mutually exclusive

because it's not possible to read and

write simultaneously

the reason why I read and write and

other control signals are active low is

power consumption considerations

okay so the CPU outputs the binary value

of 44 206 to the address bus

now to let the ROM chip know it intends

to read the contents of this memory cell

it also activates the read line

you might wonder now why would the ROM

chip need the read signal if read is all

it can do and the CPU cannot write

anything to it

well thing is the CPU has no idea what

type of memory it's addressing

actually doesn't care

so every time it wants to read something

no matter if it's ROM or Ram it's

reading from it will always pull the

ridline low

and in fact the ROM chip does need the

read signal because it needs to know

when exactly it's supposed to send the

data requested to the CPU

looks like now we need a mechanism to

transfer data

and here comes to play

the data bus

probably the most important and also

complicated communication system in a

computer and it's bi-directional in our

example the data bus carries exactly

eight bits of data

because the size of the data bus

directly affects the performance of the

entire system it is precisely this that

we mean when we say for example that the

computer is 8-bit and the game console

is 16-bit and the version of Windows is

32 or 64-bit

in response to the cpu's request the ROM

chip puts the contents of the memory

cell located at address

44206 onto the data bus

let's say the value is 112.

naturally the data will also be

presented in binary format

112 will look like this

while the read operation is in progress

the CPU becomes the receiving side and

its data bus lines act as inputs and the

ROM chips data bus pins act as outputs

our little computer here has an 8-bit

data bus which means the size always

single memory cell is one byte which is

exactly 8 Bits

so our CPU has read exactly one byte of

data and its value equals 112.

like I said before the ROM chip contains

firmware a computer programming machine

code written by a programmer

so 112 which is again just a sample

value I picked is the command that tells

the CPU to perform a certain task

these commands are also called operation

codes opcodes or machine code

instructions

so imagine it's the instruction to write

a value of 205 to the memory cell

located at address 62 088

please allow me to add a ram chip to

write to to our improvised computer

it will be connected in parallel to both

the address and the data bus of our

system

like I said the address bus is

unidirectional and in theory we can

connect an infinite number of devices to

it

but now we got a problem

when the CPU initiates a read or write

operation because we now got two memory

chips in our system how would they know

which one the CPU is addressing

if both of them get activated

simultaneously their outputs will

struggle and we're going to have a

collision on our data bus

here another very important mechanism in

computer engineering comes into play

it's called address decoding

the term decoding here has nothing to do

with ciphering or encryption

it's merely a set of logic gates that

output logic 0 whenever a certain

pattern of ones and zeros is present on

its inputs

what exactly this combination should be

is determined by the Circuit of the

decoder itself

so in order for the CPU to know exactly

which device it's addressing when

designing a computer system all address

space is divided into ranges

some part of it is taken by Rome another

part by Ram

imagine a book that has several chapters

we know exactly which page each chapter

starts and ends in

and it's impossible to move chapters if

the book had already been printed

same thing happens in a computer's

address space

each memory device is assigned a certain

address range which is fixed and cannot

be altered

the size of the entire address space is

determined by the number of address bus

lines and is always tied to the CPU

model

our computer here has a CPU with 16

address lines so the maximum number of

bytes the CPU can address is 2 to the

power of 16. which is 65

536 bytes or 64 kilobytes

you can also come up with this number

using Windows calculator

16 binary Ones Will yield a decimal

value of 65

535 because memory cell number one mind

you as the address 0 not 1.

so the address space of our computer

starts at byte number zero and NZ byte

number 65

535 and the total number of bytes that

can be addressed is 65 536.

for the CPU to be able to work both with

ROM and RAM

we need to wire them in such a way that

they're activated whenever accessing the

address range that is assigned to each

of them based on our concept

or we can say these two chips must be

properly decoded

to keep things simple in our little

experiment each chip will have exactly

half the memory space which is 32

kilobytes a piece

ROM will take the lower 32k and RAM the

upper 32k

so the ROM will be located in the

address range from 0 to 32

767 and Ram from 32

768 to 65 535.

why exactly like that and not the other

way around

ROM is usually placed at the start of

the address space because that's where a

typical CPU starts program execution

after the reset signal arrives

when you hit reset what you actually do

is zero the program counter PC

so address 0 is where the very first

firmware instruction must be located

all data between the CPU and memory

chips will naturally be transferred in

binary format

here's what it's going to look like

to be honest these numbers do not really

fit well with the ear and are pretty

hard to perceive

so in computers and programming a

hexadecimal numbering system is used

it differs from decimal system and that

in addition to digits from 0 to 9 Latin

letters from A to F are used that also

act as digits

so hexadecimal uses a total of 16 digits

instead of 10.

in essence the hexadecimal system is a

simplified way of representing binary

numbers

it basically boils down to a simple

replacement of every combination of four

binary digits there are also 16 of them

with one hexadecimal digit like this

so 8-bit of binary data can be

represented by two hex digits while 16

bit of binary data will take up four hex

digits and so on

by the way in programming four bits are

called a nibble 8 Bits are called a byte

and 16 bits and up are called a word

now these values will look like this and

our ROM chip will decode to addresses

from 0 to 7 FFF while the ram chip will

take up address range from 8000 to ffff

we must pronounce hex numbers by a

single digit because 8000 is not 8 000.

it's a different number

hex numbers have their own designation

and programming for example the C

language uses prefix Ox while in

Assembly Language Latin letter H H for

hex uppercase or lowercase doesn't

matter is appended at the end of the

number

all these designations are equivalent

okay let us take a close look at these

values and try to figure out how they

differ in terms of address Buzz bits

their binary representation tells us

that their distinct difference is their

most significant bit

any HEX number in the range above 7ff

has the highest address line that's a15

equal to 1.

any HEX number below 800 has address

line a15 equal to zero

so we need the ROM chip to activate when

a15 is low and RAM chip to activate when

a15 is high

memory chips have a special control line

for Activation called CS chip select or

C chip enable which is basically the

same

the Cs signal is also active low

if the IC is not active its outputs will

be in the so-called z-state High

impedance

which means that the pin is effectively

disconnected

such outputs are also called Tri-State

memory ICS also have the OE control

signal which stands for output enable

since ROM can only send data the Cs and

oeither have basically the same meaning

but for Ram active OE means the data is

being read from the memory

so to decode these two memory ICS all we

have to do is use a simple inverter gate

the ROM c signal will be wired directly

to the a15 address line and ram C will

be fed from the inverter

the read signal will be wired to the

output enable pins of both chips while

the right signal will go to the right

enable input of the ram chip

the right signal is not used with the

wrong chip naturally

before us ladies and gentlemen is the

real working Circuit of the simplest

computer

so how does it work

once the CPU is reset its address

pointer the program counter PC is zeroed

so all address lines are set to logic 0.

as the CPU immediately starts reading

program code from memory it sets the

read line low

because the CE line of the ROM chip is

also pulled Low by the a15 address line

the ROM IC activates

and puts up the contents of the

requested memory cell address 0 on the

data bus

although Ram is wired to all buses in

parallel it does not interfere because

it's not active

it's CS input is fed logic high from the

inverter and its data lines are in the Z

State effectively disconnected

now imagine the CPU reads the upcode

that instructs it to write byte AA 1070

decimal to address b00 45 056 decimal

the CPU sets its address bus to this

value in binary format

then it puts the integer number AA which

is

1010101 or binary on the data bus

the AA and 55 bytes alternating zeros

and ones is the value often used in

programming for memory testing

so we got the binary representation of a

a integer on our data bus

what happens next is the CPU pulls the

right line low and the ram chip mind you

the a15 is high and CS is low which

means it's active performs the right

operation storing value a a in a memory

cell whose address is b00

now this data is stored and whenever the

processor needs it it can read it

to do this it has to set the address bus

to b00 and pull the read signal low

the chip enable line of the ram chip

will also be pulled Low by the inverter

and it will place the contents of the

memory cell b00 on the data bus and the

CPU will read it switching its data

lines to input mode

okay so we have created a contiguous

address space of 64 kilobytes covered by

two memory chips

the CPU has no idea about the structure

it simply accesses a Cell by address and

receives data and each of the memory ICS

responds to the CPU based on which range

the address requested belongs to

in real computers decoding is of course

much more complex

the decoder can use several address

lines and other signals to obtain a

narrower address range

using this mechanism several memory and

input output devices can be decoded

in any case it's up to the developer to

decide which address range each memory

chip must be decoded

and when firmware is written the

programmer naturally must be aware which

devices decode to which address range

for example every personal computer has

this thing called display memory area

also known as video Ram or vram

it's basically your regular Random

Access Memory however writing data to it

changes the contents of the computer

screen

typically vram memory cells are located

according to their position on the

screen that is from left to right and

from top to bottom the lower address is

the upper left corner the higher address

is the lower right corner

all those are maybe exceptions

now we have studied a very important

mechanism that explains the interaction

of the servo processor and memory

devices

with this knowledge it's easy to

understand the principles of operation

of any computer

but it seems our virtual PC is missing

something

it does not in any way interact with the

user

all real computers in addition to memory

have input output ports this is where

you plug in your keyboard mouse or

gamepad

to work with ports the CPU also uses

read and write operations

but they are decoded into a separate

address space and accessed with separate

machine language instructions

the address bust used however is the

same so to separate ports from memory

devices there exists additional signals

on the control bus called input output

request Iowa REC and memory request

memric

traditionally their active level is also

low

so for the CPU to be able to talk to

memory correctly we must also decode the

memory request signal

here's what the schematic will look like

then

now both memory chips can get a logic

low on their chip enabled inputs only on

condition the memory request line is

also low

so what are we gonna do with our little

computer now

say we want to impersonate Arduino and

Flash an LED

let us add a simple one bit output port

to our system

we will use add d-type flip flop to

implement it

the data input will be wired directly to

the data bus

while the clock input needs to be

properly decoded

let our Port use the address FF

this number corresponds to eight ones in

binary

like I said CPU uses the same address

bus to the code ports so we will need an

and gate with 8 inputs to track this

combination on the address bus

our Port will be right only so we also

need to decode the cpu's bright line

the device must react only to Port

output instructions and ignore memory

right instructions so we also need to

decode the input output request signal

if we don't the CPU won't know how to

differentiate between memory cellff and

port number FF and when it performs a

write operation both will be affected

okay

let us analyze the circuit step by step

say the CPU wants to turn on the LED

so it executes a machine code

instruction that writes value 1 to Port

FF

as we have wired the flip-flop D input

to the d0 line the state of the LED will

correspond to the least significant bit

LSB of the data byte

so the CPU sets the address lines from

a0 to A7 to 8 ones that's value FF and

puts up logic 1 on d0 line

then it pulls the right and input output

request lines low

at this very moment the flip-flop will

be clocked at the scene Boot and data

will be copied into the register

the LED will illuminate

to turn the LED off the CPU must perform

exactly the same action except the value

written to the flip-flop board must be

zero

this principle of parallel connection

and individual addressing of peripheral

devices with the help of decoding has

been used in computer engineering for

decades

and that's exactly how Isa and PCI buses

and personal computers work

all slots and such systems are connected

in parallel and decoding happens on the

expansion cords inserted

if you've ever used the ISA Sound

Blaster you remember you had to set up

its address and interrupt line

what you were actually doing is setting

up its decoder chip

so any expansion card can be inserted

into any slot and will work the same way

however starting with a PCI Express Bus

manufacturers have abandoned this

principle and today each motherboard

slot has independent lines for

communication with every individual

expansion board installed

and that would be it for today I hope

you enjoyed this video and learned

something new

if you did make sure to give it a thumbs

up and hit the Subscribe button if you

haven't already

and please don't hesitate to share it on

social media

this was Ron matino

take care see you soon

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