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I have been reading the bool 'The Elements of Computing Systems' and I have designed a circuit for the computer that will use 1232 NAND gates, which assuming that there are 4 on a chip, is 308 chips. I believe that this number of gates, whilst still a large amount, is in the realm of possibility.

The issue if that I do not have much knowledge in the electronics, I am more into the computer science side of it, and i know that these logic gates are, unfortunately, not perfect. What should I look out for on the datasheets of these gates for my uses?

Any help would be greatly appreciated!

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  • \$\begingroup\$ What voltage and frequency are you planning to use? \$\endgroup\$
    – CL.
    Aug 7 '20 at 10:50
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    \$\begingroup\$ If you do not have much knowledge of electronics, a 308-chip project is not an ideal beginning. What is it you want to learn? Wouldn't a simulator be easier? \$\endgroup\$
    – CL.
    Aug 7 '20 at 10:52
  • \$\begingroup\$ My guess is that the easiest to use would be CMOS logic, like the 4011 (Example: assets.nexperia.com/documents/data-sheet/HEF4011B.pdf ). HOWEVER this is an old design, it can not run at much more than a few MHz so beware of that. But my biggest concern is that about complexity and experience. If you build something so complex with 308 ICs without much building experience then I guarantee you that you will fail. You should start with much, much simpler projects with 2 or 3 ICs to gain experience.... \$\endgroup\$ Aug 7 '20 at 11:30
  • \$\begingroup\$ ... If you directly build the 308 ICs design, it will not work and you will have wasted your money. Using a simulator is indeed a much simpler option. Also note that FPGAs exist into which you can load your design and test it. There are tools that simulate an FPGA so that way you don't even need the FPGA chip itself to simulate the behavior. \$\endgroup\$ Aug 7 '20 at 11:31
  • \$\begingroup\$ I'm really not sure about the voltage and frequencies I will be using, i would like the frequency to be as high as possible, but I am not actually going to be using the computing power for anything, its just a fun side project whilst i do my degree. In terms of using a simulator, I designed the circuit on a simulator provided by the creators of the book and it works for that. I will almost certainty start with smaller projects, and build up to the CPU, but I would like to know what gates i should buy, so i dont need to buy different ones later. I'll take a look at the 4011 \$\endgroup\$ Aug 7 '20 at 11:33
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a CMOS part like CD4011 ot 74HCT00 is a good choice, they are reasonably energy efficient which important if you're running several hundered chips. maximum clock speed won't be spectacular, but should be enough to run demosnstation programs.

if you assemble the CPU in parts and test each part you should eventually have a working machine.

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    \$\begingroup\$ HC is probably a better choice than HCT. Noise immunity is better, for one thing. Since he's building from scratch, there is no obvious reason to assume TTL levels and compatibility. \$\endgroup\$ Aug 7 '20 at 12:03

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