Computer From Scratch

DeletedAccount · Post by **DeletedAccount** » Sat Jul 14, 2007 12:28 am

Do you know any information on how build computers from
scratch ... not by using componets purchased from the market ...but
by developing a circuit and building it using IC's of course is permitted........

AndrewAPrice · Post by **AndrewAPrice** » Sat Jul 14, 2007 4:30 am

A CPU is an IRC.. But even for more of a challenge, look up how how digital circuits work.. and try building your own digital AND, NOT, OR, and XOR gates (you don't even have to use electrical components, fluidics uses water). Then using your digital gates, build a basic 4-bit binary adder (accepts 8 on/off signals, exports 4), then work your way up by adding an extra input (to select between multiply or add) and you have yourself a basic arthritic unit! Then try building a series flip-flop (which can store an on/off bit) (build a few series of them, one to store a number in, one to store the result in, one to store the action to perform in, and one to store as the instruction 'counter'), and on each electrical pulse, have the circuit perform it's logic, and increase the instruction counter.

Then you have yourself a 4 bit computer!

I'd recommend using an electronics simulator and not building it by hand.
An IC is basically an entire digital circuit in a tiny chip that you can just plug into your board. There are plenty of electronics companies where you can get one produced if you send them your design. Then you just have to connect the pins of your IR chip onto a circuit board, which attaches to your ports, power supply, etc.

Kevin McGuire · Post by **Kevin McGuire** » Sat Jul 14, 2007 5:06 am

An IC is basically an entire digital circuit in a tiny chip that you can just plug into your board. There are plenty of electronics companies where you can get one produced if you send them your design. Then you just have to connect the pins of your IR chip onto a circuit board, which attaches to your ports, power supply, etc.

There are thousands of ICs. Most are extremely cheap by themselves (cents on the dollar), and some provide a array of gates such as: AND, NOT, XOR. You can also find lots of IC that already provide a basic four bit binary adder or a flip flop for usage in your circuits.

A actual item model in the series: a Quad 2-input NOR gate.
http://www.jameco.com/webapp/wcs/stores ... tId=867886
A series listing for the category:
http://www.jameco.com/webapp/wcs/stores ... yId=104201
The categories:
http://www.jameco.com/webapp/wcs/stores ... egoryId=10

You have to buy thousands of parts to even submit a order, but some places let you buy just what you want:
http://www.goldmine-elec-products.com/d ... ?dept=1144

You might want a breadboard too, but I in NO way say this is the site to buy them. Just trying to show you what they are:
http://www.goldmine-elec-products.com/p ... ?dept=1293

As a matter of fact I might buy that breadboard. =)

Pyrofan1 · Post by **Pyrofan1** » Sat Jul 14, 2007 5:13 am

you might want to try microcontrollers too, this one is 32 bits and can access mice, keyboards and can output VGA.

Kevin McGuire · Post by **Kevin McGuire** » Sat Jul 14, 2007 5:31 am

you might want to try microcontrollers too, this one is 32 bits and can access mice, keyboards and can output VGA.

Those look really neat! They have eight cores in each die.

I think the really cool part to micro-controllers is digital signal processing. I am so excited to one day build one. You just need to interface a ADC(Analog To Digital Converter) to the micro-controller, and if you are sending then interface it with a DAC(Digitial to Analog Converter).

I have hand built a ADC before using a 555 timer incrementing a binary counter in which the outputs feed a resistor network that hooked into a OPAMP used as a comparator. The other input to the OPAMP was the signal. The problem is it was slow but not slow as in seconds just not enough to even convert a 10KHZ AM signal to digital data. I might have been able to get a lot faster if I had used a more expensive and higher quality timer than the 555. Also, the method I used to build it was not the best at all for speed. Anyway, just really really cool what can be built using this stuff.

Pyrofan1 · Post by **Pyrofan1** » Sat Jul 14, 2007 5:51 am

Those look really neat!

they are, i have two of them, but i haven't been using them much because wine can't emulate the programming software.

Kevin McGuire · Post by **Kevin McGuire** » Sat Jul 14, 2007 5:58 am

Have you actually got them running, yet? If so what type of configuration did you use to boot them?

Pyrofan1 · Post by **Pyrofan1** » Sat Jul 14, 2007 6:14 am

sorry for the crappy picture
http://s176.photobucket.com/albums/w199 ... 0_2130.jpg

Combuster · Post by **Combuster** » Sat Jul 14, 2007 6:44 am

Using raw gates to build your own system is a bit overkill. I'd start with an AVR processor and build a chipset around that. The documentation for those chips are pretty well available

Kevin McGuire · Post by **Kevin McGuire** » Sat Jul 14, 2007 7:55 am

I am guessing the clock circuit is on that PCB? Have you been able to interface some RAM with the CPU yet; and did you have any problems?

I have two Z80 chips, but have not got around to working with them much. Hopefully, the new breadboard I order a few hours ago will help give me more space to work on stuff. I always run out of room. =)

Pyrofan1 · Post by **Pyrofan1** » Sat Jul 14, 2007 8:06 am

I am guessing the clock circuit is on that PCB?

the chip has an on board clock that can run at 20 KHz or 12 MHz

Have you been able to interface some RAM with the CPU yet

it has 32 K of RAM on board

and did you have any problems?

nope

Dex · Post by **Dex** » Sat Jul 14, 2007 8:33 am

I built one of theses: http://www.xgamestation.com/
This was also a good project, but is not finished yet
http://webpages.charter.net/greener/electronics/

AndrewAPrice · Post by **AndrewAPrice** » Sat Jul 14, 2007 6:14 pm

Dex wrote:I built one of theses: http://www.xgamestation.com/
This was also a good project, but is not finished yet
http://webpages.charter.net/greener/electronics/

That looks cool! I tried building my own game console, and I wanted to order a GoForce from NVidia, but you had to pay a license fee and then get put on their waiting list while you register as an official hardware developer.. :/

Kevin McGuire · Post by **Kevin McGuire** » Sat Jul 14, 2007 6:48 pm

I really like robotics. I wish I could find some small hydrological cylinders (have not looked much), or find some innovative way to build one out of the shell of a ink pen...

Stick a 10000 pound motherboard on top and watch it squirt oil everywhere as the ink pens busted.. never the less.

DeletedAccount · Post by **DeletedAccount** » Sun Jul 15, 2007 11:27 pm

I would like to follow the approach suggested by Combuster....
but i am clueless as where to start and i only have an elementry
or u can say moderate ( i know how to set up counters's , differentiators
, small signal amplifiers etc ..... ) Can any one give me some direction.......

OSDev.org

Computer From Scratch

Computer From Scratch

Hmmm.... very interesting........