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Step 15: Buying Parts

The great thing about building an 8-bit computer is that most parts will cost you less than a dollar a piece if you buy them from the correct place. I purchased 90% of my parts from Jameco Electronics and I have been completely satisfied with their services. The only parts I have really bought from anywhere else are the breadboards and breadboard wires (and the Numitron tubes). These can be found considerably cheaper on sites like Amazon. Always be sure to make sure the parts that you are ordering are the correct ones. Every part that you buy should have a datasheet available online that explains all of the functions and limitations of the item that you are buying. Make sure to keep these organized as you will be using many datasheets in the construction of your computer. To help you with your computer I will list the parts that I used for mine:

4-Bit Counter:
74161 - http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?freeText=74161&langId=-1&storeId=10001&productId=49664&search_type=jamecoall&catalogId=10001&ddkey=http:StoreCatalogDrillDownView

4-Bit Register (I use two for each 8-bit register):
74LS173 - http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?freeText=74LS173&langId=-1&storeId=10001&productId=46922&search_type=jamecoall&catalogId=10001&ddkey=http:StoreCatalogDrillDownView

2-1 Multiplexer:
74LS157 - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_46771_-1

16x8 RAM (output needs to be inverted):
74189 - http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?freeText=74189&langId=-1&storeId=10001&productId=49883&search_type=jamecoall&catalogId=10001&ddkey=http:StoreCatalogDrillDownView

Full Adders:
74LS283 - http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?freeText=74LS283&langId=-1&storeId=10001&productId=47423&search_type=all&catalogId=10001&ddkey=http:StoreCatalogDrillDownView

Tri-State Buffers:
74S244 - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_910750_-1


XOR Gates:
74LS86 - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_295751_-1

AND Gates:
74LS08 - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_295401_-1

NOR Gates:
74LS02 - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_283741_-1

Inverters:
74LS04 - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_283792_-1

Ring Counter:
CD4029 - http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?freeText=4029&langId=-1&storeId=10001&productId=12925&search_type=jamecoall&catalogId=10001&ddkey=http:StoreCatalogDrillDownView

JK Flip-Flops:
74LS10 - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_295427_-1

<p>Great manual!</p><p>I've made it using Your design, but on an unusual medium: pixels :D Here's the simulator if you wanna see this in motion operating: <a href="https://realhet.wordpress.com/2015/09/02/bitmap-logic-simulator/" rel="nofollow">https://realhet.wordpress.com/2015/09/02/bitmap-lo...</a></p><p>I programmed it to calculate the Fibonacci series, it has an extra 16 byte ROM for the program, the fetch is only 2 cycles and different instructions can break the micro-word sequence earlier as when they finish, so instruction times are ranging from 3 to 5 cycles.</p><p>It was fun to input a program only using switches, like in ancient sci-fi movies. Well, it was fun for the 1st time... After I rather made a ROM.</p>
<p>Good job bro...Nice software</p>
<p>Realhet, that is spectacular! I really like your idea of using simple CA rules to make a logic sim. It is almost like Redstone in Minecraft, but so much more powerful and less latent (and also devoid of a jungle of wires, that must be nice). Congrats on the great project. Do you know of any other users of your program yet? I'll make sure to keep an eye on your site for updates, and I'll share your work with my friends. I'm sure they will really enjoy it.</p>
<p>can someone please tell me the part list with the total no. of them used. </p><p>i did saw the part list but not the total number. I havnt read the whole tutorial yet so before i start would love to have evrything beforehand. and also please can anyone tell me based on this how much would i be able to increase its functionality . </p>
<p>Hi, don't start counting how many ic's you need... Just study the first component (I recommend clock, mar or program counter), design it and buy the integrated circuits you need. Do the same for all the components.</p><p>Not giving you the exact number and id of integrated circuits means that you can develop YOUR solution</p>
<p>How did you decide between active-low and active-high bits?</p>
<p>I mean for the control words that you used.</p>
<p>Subscribed just to push &quot;I Made it!&quot; button and to say a <strong>BIG</strong> thank you to K.H.! :D</p>
<p>Wow! I love the modular setup of the boards. That is a fantastic idea both aesthetically and functionally. I ran into EM interference issues with my breadboards' close proximity. I would imagine a setup like this has much less of a problem. Congrats again!</p>
<p>and what do you do with the carry out of the lasy 1-bit adder?</p>
It gets connected to the carry in for subtraction operations
<p>Help, I am trying to build a 8 bit computer from this but I don't understand, im building this so I can show off to my little brother... I don't understand how many chips he used and I dont understand anything past the ALU's basic add and subtract, and the register, any help would be great, please email me at hurster100@gmail.com... Once again thanks</p>
<p>What do you recommend for a power supply? I really want to do this project, but I have no idea what to do for a power supply.</p>
<p>Hi, I'm thinking about starting this project, I find it really intresting and my question is Should I make it, because I'm 17, I know binary and some eletronics, please help!</p>
<p>i want to ask about about the uses of this 8 bit computer</p>
<p>Since its 8-bit, you can do anything that requires 16 bytes of memory ( depending on your RAM ). Unless you add some external drive... which would allow you to do so much more. But just with 16 bytes of RAM you can probably do operations like:</p><p>A+B=C, then</p><p>C+B=D,then</p><p>D+A=Z,</p><p>I think.</p><p>But with an external drive of some sort your 8 bit computer will be able to do stuff like this https://www.youtube.com/watch?v=qYvr0b8jqbg ...i think?-e-dah-puzi-1998</p>
<p>16 bytes? How did you get that? Surely an 8-bit address buffer should be able to address 2^8=256 bytes of memory?</p>
<p>i am new in this topic </p><p>i think we can point to 16 Bytes memory with 5 bit address.</p><p>16 Bytes = 4 * 4 (bytes) = 32 * 32 (bit) =&gt; 2^5 = 32</p><p>am i wrong ?</p>
<p>or is it right?</p><p>to say memory we calculate this way !!!</p><p>4*16 or 5*32 or 6*64 </p><p>so if this is true </p><p>4*16 = 64 bit </p><p>64/8 = 8 byte</p><p>so for 8 byte memory we can address with 4 bit .??!!!!</p>
<p>Yeah....some people like to have a 4 bit memory address and 4 bit op code...I would personally do an 8 bit op code and memory address.</p>
<p>I mean I guess if you're not addressing much memory then it's Ok, but it would severely limit what you could do with the thing. With 256 bytes, you could even do some kind of really simple pong game.</p>
<p>Yeah....some people like to have a 4 bit memory address and 4 bit op code...I would personally do an 8 bit op code and memory address.</p>
<p>how many wires do I need? </p>
A thousand?
<p>That is a lot of wires! COOL!!!! Do you play Super Mario Bros. on it?</p>
<p>How do I use the CD4029 as a ring counter? I bought it and all I've been able to get it to do is count up/down in binary, resetting at either 15 or 9. Any help?</p>
<p>I am looking forward to making this project! I couldn't find anything like it no matter how hard I looked! Thank you for making this project available. :3</p>
<p>How do you ensure that the program counter starts out at zero?</p>
<p>What type of PROM are you using? I didn't see any parts listed for the PROM?</p>
<p>good jop, i motivated by your project, i am gonna make one sooner . i want to know how much this projects coast you ? is there any additional advice to build one like any mistakes must avoid or things that may save time ?</p>
Sure! Try using shorter breadboard wires, and plan out the layout of your computer beforehand. This will save you a bunch of grief in the future of dealing with EMF related issues and dirty clock signals.
<p>Very well structured into topics. Very well explained and crafted. Awesome job!</p>
<p>your funny</p>
<p>I think someone forgot to cable manage :P</p>
<p>Im guessing your a linus fan. ( By your picture and your comment).</p>
<p>Yes I am definitely a Linus fan :) But, my image is not a parody of Linus's image, rather its a parody of Steve Jobs famous image, so is Linus's. The comment inspiration is more Luke, not Linus. </p>
<p>thanks for all the info and references. <br>your 8 bit computer looks like a pile of wires lol. <br>its cool though. </p>
It is awesome! One question though, I didn't quite understand what your computer is capable of doing. What can it actually do?
<p>Presumably execute simply binary programs. Adding numbers, subtracting numbers, multiplication, division, maybe some more complex things like calculating square roots or powers. Anything that a standard computer can do within the limited memory it has (256 bytes).</p>
Thanks for letting me know.
<p>Are logical operations like AND , OR, NOR, or XOR essential in performing complex operations like square rooting, or a game. I just wanna know if they are needed. If so, which operation is used the most.</p>
<p>Every single kind of computation your computer does relies fundamentally on the operations of AND, OR, NOR, NOT and XOR. Actually, even AND, XOR and NOR can be composed simply of OR and NOT gates.</p>
<p>What ROM ic's did you buy.</p>
<p>Can anyone tell me which RAM IC I should buy?</p>
<p><a href="http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?freeText=74189&langId=-1&storeId=10001&productId=49883&search_type=jamecoall&catalogId=10001&ddkey=http:StoreCatalogDrillDownView" rel="nofollow">http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?freeText=74189&amp;langId=-1&amp;storeId=10001&amp;productId=49883&amp;search_type=jamecoall&amp;catalogId=10001&amp;ddkey=http:StoreCatalogDrillDownView</a>...</p><p>Two of these chips can be your 16x8 RAM</p>

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