Hi everyone,

I’d like to learn how to make a computer on a breadboard.

I got recommended a book called “digital computer electronics” by malvino. Unfortunately, it’s £150 - out of my price range.

is there another book I could get that will get me started??

kindest regards and thanks in advance for your suggestions

 

Hi everyone,

I’d like to learn how to make a computer on a breadboard.

I got recommended a book called “digital computer electronics” by malvino. Unfortunately, it’s £150 - out of my price range.

is there another book I could get that will get me started??

kindest regards and thanks in advance for your suggestions

Welcome to AAC.

What is the goal of the breadboard computer?
How much do you already know about computers—hardware, firmware, operating systems, programming?

There is a very big range of what you might have in mind.

One immediate suggestion, if you aren’t already aware of it, is the YouTube channel of Ben Eater.

He’s got a large playlist about breadboarding a 6502-based computer based on the Malvinas book, and even an operating system.

​

 

I wouldn't expect to find a book dedicated to that goal, it involves multiple subjects really too so you'd likely need several books.

Have a read of this, dig out similar articles too:

https://hackaday.com/2020/11/23/full-8-bit-computer-on-breadboards/

The guy in that video says (at 2:20) "the clock runs at a fixed rate of 1.8 GHz" which I find hard to believe...

For some real fun, consider building a computer from just relays, that's something I'd love to attempt one day myself!

 

Using what?

A microcontroller or system on a chip?

CMOS logic chips?

Transistors, diodes and resistors?

 

This is impressive:

​

needs about 30 amps at 80 volts...

 

Hi everyone,

I’d like to learn how to make a computer on a breadboard.

I got recommended a book called “digital computer electronics” by malvino. Unfortunately, it’s £150 - out of my price range.

is there another book I could get that will get me started??

kindest regards and thanks in advance for your suggestions

Hi,

What kind of parts do you want to use, like 7400 series TTL or CMOS logic.

 

This pdf document is not about building computers but how computers work.
It is a top read in my opinion.

M68HC05 Family - Understanding Small Microcontrollers

 

Hello again,

I was going to suggest some logic counters like 7493 (or similar CMOS) and some ROM memory chips and some decoder chips and something to use as an ALU Arithmetic Logic Unit).
The ROM (or RAM) is programmed with a set of instructions, the 7493's step through the ROM memory addresses, the decoder decodes the instruction, the ALU does any arithmetic required, other decoders decode input/output port addresses.
It's a simple setup but it works it's been used in commercial products back in the 1970's.
You also need a ROM programmer or some other way to set instructions into memory.

 

Welcome to AAC...
One immediate suggestion, if you aren’t already aware of it, is the YouTube channel of Ben Eater.
He’s got a large playlist about breadboarding a 6502-based computer based on the Malvinas book, and even an operating system

Thanks for taking the time to reply.

Yes Ben Eater is where i got the idea to build a computer on breadboards. I'd like the book, except it's too expensive for me, so I was wondering if anyone knew of an alternative??

 

I wouldn't expect to find a book dedicated to that goal, it involves multiple subjects really too so you'd likely need several books.

Have a read of this, dig out similar articles too:

https://hackaday.com/2020/11/23/full-8-bit-computer-on-breadboards/

The guy in that video says (at 2:20) "the clock runs at a fixed rate of 1.8 GHz" which I find hard to believe...

For some real fun, consider building a computer from just relays, that's something I'd love to attempt one day myself!

Thank you for that - I'll read the website properly soon

 

Using what?

A microcontroller or system on a chip?

CMOS logic chips?

Transistors, diodes and resistors?

Thanks for replying.

It was a book recommendation I was after.

Do you have any recommendations for a beginner for the above items you mentioned??

 

This is impressive:

​

needs about 30 amps at 80 volts...

wow

Thanks for replying

 

Hi,

What kind of parts do you want to use, like 7400 series TTL or CMOS logic.

Errrmmm

Could you provide the book recommendations for both???

Which is appropriate for a total beginner???

 

This pdf document is not about building computers but how computers work.
It is a top read in my opinion.

M68HC05 Family - Understanding Small Microcontrollers

Wow - thank you

 

Hello again,

I was going to suggest some logic counters like 7493 (or similar CMOS) and some ROM memory chips and some decoder chips and something to use as an ALU Arithmetic Logic Unit).
The ROM (or RAM) is programmed with a set of instructions, the 7493's step through the ROM memory addresses, the decoder decodes the instruction, the ALU does any arithmetic required, other decoders decode input/output port addresses.
It's a simple setup but it works it's been used in commercial products back in the 1970's.
You also need a ROM programmer or some other way to set instructions into memory.

Thank you for replying

 

Thanks everyone for replying.

Seems I need to start somewhere way way more basic.

Perhaps some fun bits with breadboards.

Can anyone recommend a beginners breadboard electronics hobby book?? something that explains everything to you??

Anyway - thanks again everyone

 

Thank you for replying

Hello again,

Oh you are welcome. I happen to have a lot of experience with this because way back in the early 1970's before computers were so widespread and even microprocessors were widespread i worked for a company where we had to design our own computers using discrete logic like TTL 7400 series and ROM memory chips we had to program by hand, and for the ALU we used a very early model calculator chip which we interfaced to the rest of the board. The board was something like 8 inches by 10 inches and all it did was process the instructions in the little ROM chip and interface with the calculator chip. Was quite a project. Now, the same thing is done in a tiny chip you can get for $1.00 USD and some you can even get as small as 5mm x 5mm size. It's incredible how small things have gotten and how powerful, like the PIC line of microcontrollers. Our board was really meant to be used like a microcontroller because it was used for machine control.

Good luck with your project and if you get around to building one maybe you can post some pics here. Would be interesting to see.

 

Errrmmm

Could you provide the book recommendations for both???

Which is appropriate for a total beginner???

Hi,

You mean which type of components or what books?

The 7400 series TTL is easiest to learn i think, and there are the LS versions 74LS00 and CMOS versions which use lower power.

As far as a book, what aspect do you need to learn about. Soldering, parts choices, schematics, etc.

I could draw you up a quick working diagram that would show how the components go together, you'd have to study the chips being used though.
You can get so much data online now. If you look up a chip like the 74LS00 you will get an entire data sheet that shows the pinout and internal workings of the chip. The 74AHC00 series is a CMOS series equivalent to the old 7400 series and uses much less power and allows a wider range of power supply voltages, from i think 3v up to 15v but double check that range. You can power a lot of those chips with a battery, probably even a 9v battery.

I'll draw you up a quick diagram of the basic structure of a computer using these parts.

 

Errrmmm

Could you provide the book recommendations for both???

Which is appropriate for a total beginner???

Here is a block diagram of a system. This is probably the simplest system that can actually do anything useful.
The implementation would be done with logic gates, counters, Rom, Ram, logic decoders, etc. The counters should be the synchronous type.
This structure might be referred to as a von Neuman architecture.
If you did not want to implement the CPU part (address counter, instruction decoder, ALU) you could start with a simple CPU like the 8008 or z80 CPU.
As an aside, it might be interesting to program a simpler small microcontroller to act as the CPU with an external address counter. It might be done with an 8 pin dip microcontroller. Would of course be slow, but then anything hand made these days will always be slower than the present day 5GHz CPU's available now unless you put a lot, a lot, a lot, of effort into it.

The address counters start from zero and address a byte (or bytes) in Rom, which places an instruction on the data buss. The instruction decoder decodes it and either waits for more bytes from rom or immediately controls one of the other blocks. It may for example wait for the next byte and can decode that or send it to another block, depending on what the first byte was.
For a simple system, a 74138 could be used for the instruction decoder and another for the i/o port decoder, for example.
The ALU could be as simple as a 4 bang add, subtract, multiply and divide, or even just add and subtract. Binary invert is also typical.
The data buss is bidirectional except for the Rom data.

 

As I see it, there are three (or four) options for building and learning about computers.

(1) Discrete digital logic
(2) Processor and memory, peripheral bus system
(3) single chip microcontroller
(4) ready built board system

With (3) and (4), the experience will focus more on programming rather than hardware.

In my opinion, (1) is very ambitious and tedious.
Option (2) is doable but components are becoming more and more difficult to get.

Option (3) is a very viable starting point which will provide a good path to embedded MCU applications.