I want to build an 8-bit computer from scratch. Chose the Z80 since it’s simple and there’s a fuckton of info about it.
I’m trying to design a single-step circuit for troubleshooting. I’ve read Steve Ciarcia’s “Build your own Z80” and it had a circuit for it, but he was using an original Z80 running at 2.5MHz, and I’m using a Z80A running at 4MHz.
Ciarcia’s circuit used a 7474 flip-flop and a 74121 monostable multivibrator with a 7400 (I’ll be using a 74LS74 & 74LS00) to de-bounce the step button.
I’d like to know if this circuit would still work? I’m still a bit of a noob in electrical engineering. I looked up the specs on the ICs, and the pulse width of the 74121 can be adjusted by altering the values of the resistors and caps in the circuit.
Am I worrying over nothing; can this circuit still be able to function at the faster clock speed?
>>55333685
I have experience playing 8-bit games and listening to 8-bit music. Does that count?
>>55333707
Yeah, I've got that too?
Didn't help I'm sorry to say.
>>55333685
What does this have to do with the RX480?
>>55333819
this
>>55333685
They will work just fine
t. guy with ee masters degree
>>55333871
Thank you!
I know the z80 executes an instruction once every 3-4 pulses of the clock. I just didn't want the step circuit to make the MPU execute more than one operations because of the faster clock frequency.
>>55333819
>>55333848
Fuck off to your containment board
>>>/v/
>>55333913
>computer part discussion belongs in /v/
hahahah, welcome newfriend. And I suppose discussion of laptops and phones belong on /v/ too because you can play games on them?
And programming discussion belongs on /v/ because it's used to make games
give me a break
>>55333685
>Build your own Z80
Cool project anon. I wish I could help more, but I have only done logic design, not the actual electrical work, although I should be able to.
Just to help out, here's the data sheets:Z80: z80.info/zip/z80cpu_um.pdf
7400: ti.com.cn/cn/lit/ds/symlink/sn74ls00.pdf
7474: ti.com.cn/cn/lit/ds/symlink/sn74ls74a.pdf
74121: ti.com/lit/ds/symlink/sn54121.pdf
At first glance I see no reason why it shouldn't work, but I need to study the circuit a little more. If any tweaks need to be made to the multivibrator, then the datasheets will have schematics and equations to design such a circuit. I say give it a try; the worst that could happen is you lock up your Z80 and have to pull RESET.
I wish I had grown up in the 70s. Why don't things like BYTE magazine exist anymore??
>>55333928
Play mental gymnastics all you want, it doesn't change shit.
>>55333928
I can't think of a single place on 4chan where programming, laptops and phones are being discussed, so I dont really see your point.
Hi my friend
It appears that you have come to the wrong board
Let me re-direct you to >>>/diy/ for further information surrounding such topic
Good luck
>>55333934
Thanks.
Going to start out with a MPU tester without RAM or ROM to start.
Still working on the crystal oscillator clock circuit.
There are a couple clock circuits that use a 555. Might go with that for the first test and run the z80 slow.
>>55333968
actually /sci/ would be more appropriate.
Honestly, /g/ should be split into a software board and a consumerism/hardware board
>>55333968
Didn't even think to check here.
Thank you.
>>55333901
I never looked into z80 but i guess you could just underclock it if timing probems occur
>>55333973
Also look at CD4011BE IC's for oscillators
You can have much more fun with your circuits that way
>>55333975
You don't visit /diy/ do you consumerweeb?
>>55334034
sorry, no, i'm from /v/
but why wouldn't this be a good thread on /sci/? it looks like science
>>55334075
It's a DIY project. DIYers post on /diy/. I mean OP can try /sci/ if he wants but /diy/'s the place to go if he wants the best chance of getting advice.
>>55333685
if you are worried about the circuit not working at different speed what you have to do is look up the propagation delays for each chip in the circuit then work out the time it takes the clock signal in total to get from one end to the other.
draw the clock as it would come out of the output then compare it to the minimum timings required for the processor.
HTH.
>>55333819
Fucking kek. If you don't see the humor then you need to lighten up
>>55334185
That is why you get LS TTL. No way the ancient Z80 could outpace those.
>>55333913
>>55333936
you need to die
>>55334234
y tho
I made an 8-bit computer for an FPGA in my computer architecture class. Was pretty cool. I've been wanting to do something like that in hardware, though.
