Okelo Profile picture
Electrical Engineering graduate with a focus on: Embedded Systems, FPGAs and Signal Processing. Producer of “Mhandisi: The Engineer’s Podcast”

Aug 7, 2020, 26 tweets

Friday Night Hacking, August Edition #FridayNightHacking #electronics #arduino #raspberrypi

Building memory

Sigh, one of my RAM chips has failed me, it's going to be an almost 6 week time sink before I can acquire a replacement 😞.

Making slow progress, but having a good time of it.

The RAM:
Yellow -> Addresses
Red -> Stored Data

Stored Data corresponds to the address accessed (just for test purposes 😁).

#8bitComputer #electronics #engineering #arduino #raspberrypi

The completed modules thus far. Only 1.2 more kits left and the bus to put together. That is going to require a lot of conducting

#8bitComputer

A splash of colour after a build

Hello Friday!!!

been waiting for a replacement 74LS189 RAM IC since August, at last I should be getting it this week.

Never ever shipping with 4PX ever again 😭😭😭

sweet

Keeping a strict colour coding scheme really makes working on circuits super easy. Always remember, you will forget.

TIL that the choice of LED on a timing circuit can greatly affect the operation of a program counter: Blue is good; Red and Green are bad.

#8bitComputer #electronics #engineering #arduino #raspberrypi

adding a resistor in series to the LED seems to mitigate this issue

the final countdown. could be done by New Year's, bit what's the rush 🤷🏾‍♂️

minor setback on the EEPROM department. good thing though it is the ground pin, have a couple of workarounds i could consider: solder a new pin or solder the pin to another ground pin. I'll go with whatever is aesthetically pleasing

The Arduino Nano based EEPROM programmer all built out 🔥🔥🔥

#8bitComputer #electronics #engineering #arduino #raspberrypi

The Program Counter

most of the modules are already in place, what’s left is building out the control logic, that’s going to be most taxing conducting work 🥵

Finally decided to get back on the 8-bit computer bandwagon, and wouldn't you know it, one of the NAND gates was faulty. Glad I caught it before moving on to the next stage which is going to involve a lot of conduiting and troubleshooting would've been hell.

Solving Simple Arithmetic on an 8-bit Simple as Possible (SAP) Computer

this video was fun to make (😝), moving data between registers to solve an arithmetic problem.
still have to build the control logic, but i now have an appreciation of what it does

I'm aiming to be done with 90% of this project by tomorrow, which I think is feasible. I did get myself a new set of strippers, which should make my work easier 😁

ah, it is troubleshooting time to mitigate the effects of stray capacitances/inductances or floating pins

90% done. Running a set of instructions to calculate: 16+24-32.

Still a couple more optimizations left, but I think the bulk of the work is handled!!!

FrankenLEDs, ready to plug and play 🙌🏾

and that's a wrap on my build of the 8-bit simple as possible computer 🥳🎉, it was a wild ride

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