Author Archives: paul

Day 9: The search for a working Assembler

My patience is running thin, but thanks to some folks on the RC2014 for pointing me in a few possible directions. First of all.  Xmodem. Somehow my terminal settings got changed, and I couldn’t get files transferred.  You need RTS/CTS … Continue reading

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Day 8: Z80 Assembly in CP/M

I need to find a Z80 assembler that runs in CP/M (if such a thing exists), and I need to figure out how to get it onto my RC2014 that’s now running ROMWBW. B:XM.COM is Xmodem, a popular tool for … Continue reading

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Day 7: Z80 Assembly, CP/M & Failing at stuff

This’ll be a short post, and in fact, I’m writing it the following day.  Yesterday I beat my head against the wall failing  & flailing.  I got some things blinking, so.. yay, but kept getting all sorts of compiler errors, … Continue reading

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Day 6: RC2014

Changing domains for a bit, and getting back into my Z80 based RC2014 computer to learn how to manipulate the the timer.  The timer is a separate chip, a Z80 CTC, and the board is designed by Dr. Scott Baker.  … Continue reading

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Day 5: Dual Range, Adjustable Multivibrator w/ Eurorack Out

OK, I swear, I’m done subjecting y’all to this dumb little circuit.  I’ve added a switchable range, which gets me down to ~ .1Hz, and another pair of transistors fro a clean output pulse of about 8v, suitable for Eurorack … Continue reading

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Day 4: variable speed multivibrator

When in doubt, add another transistor. I’ve got it working from ~ 1Hz to 11Hz.. Not too bad, though I’d like even more range on a single control. View this post on Instagram A post shared by Paul Carbone (@toomanyoscilloscopes)

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Day 3: variable speed multivibrator

The thought occurred to me late last night that I could replace the resistors that governed the rate of charge for the capacitors with transistors so that I could vary the rate. Turns out I was right! View this post … Continue reading

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Day 2: More on the Multivibrator

I wanted to look at this circuit in more detail to understand what’s going on. I’m probing the collector of Q2 on the yellow trace, and the base of Q2 on the green trace. Note that the time off and … Continue reading

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Day 1: The Astable Multivibrator

How do you blink a light with only discrete components? The Astable Multivibrator, which is a type of relaxation oscillator. ‘Astable’, meaning it’s keeps flipping between two states, and never rests in one (we’ll see this later when exploring the … Continue reading

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Day 0: LDR

We’re officially starting the 50 days tomorrow, but I started layout out parts and ended up jumping in.  This is obviously not how you’d make a light blink on it’s own, but I just stated messing around with a few … Continue reading

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