Since I last worked on the PCB design, there have been many changes. And after looking at the availability of the chips, I found that several of them were not in stock (in DIL version). And since the design has become faster, it is not as easy...
LOGISIM simulatorThe design was only tested on the logical level, in the Javascript simulator. Before making a PCB I wanted some form of confirmation more on the hardware level, so I entered the design in the good old Logisim. Nowadays there...
It's rare that a PCB is perfect on the first go. In the case of my PPI module, this is the third set of 5 boards and we're into minor improvements now. It's nicely refined now. I've gone for a latching connector. It's essential - not for latching the...
Not all GPS receivers are alike! The GPS receiver I first ordered on Amazon is not designed to be used as an accurate time source. Don't get me wrong, the U-Blox NEO-6M is a good receiver but it was designed as a general-purpose GPS receiver. It processes...
The original HC-12 appears to come from the HC01 factory. Clones have been made of this module, some of which had bad quality components, which left the range much less than advertised!! (Search Hackaday for HC-12). The module is simple and easy to use,...
I realized that the flip-flop chip 74LS173 is obsolete and no longer available.Replaced the obsolete 74LS173 with other TTL flip-flop 74LS175.Added jumper and switch for manual step clock operation,Added 5v voltage regulator and bypass capacitors.The...
In this chapter I show you the main features of Raspberry Pi 4B, Qwiic pHAT module and AS7263 sensor. Raspberry Pi 4B This product’s key features include a high-performance 64-bit quad-core processor, dual-display support at resolutions up to 4K...
I am going cra5y ! It works sometimes, and not other times, for identical input. It is not initialization (I think) because the badge says everything (Registers, RAM etc) is zeroed on start of Run. I can see that sometimes when I enter a "A" on my terminal...
So it's been six days since update number 2, several of which were spent in a town in Ohio where the biggest tourist attraction was having a really short street. I had the opportunity then to think, reflect, and reach out to the hospitals and universities...
waiting on a USB ttl cable so I can check and see if there is anything on the boot log, if I have to get a new pi that would more than double the budge of the build, bah. Pulled some batteries out of my laptop that died previously in the project:...
This is definitely the "12 pages of waffle no one reads before the recipe", but I feel it gives much needed context to the origins - the primordial soup - of this project. So really, what even drove me to build my own Lisa? Two things really....
Yeahhhhh, I did say I'm not great at documentation. But before I completely forget, here is a quick run down of things I found during building the Lisa. 1) On the CPU board by Warmech, there is a capacitor at C43. On an original Lisa,...
The main PCB board will be kept, as it holds the case together. There are three plug-in modules that will be removed. On it are logic chips (some AND/OR gates and many flip-flops). Looking at the six small boards with the nixies, it becomes clear that...
2023-09-02 This is the approach I have decided upon. Use GAL chips to mop up the small-scale TTL logicMerge ZX81 and G007 logic togetherTTL chip for keyboard input bufferTTL chip for NOP driverTTL chip parallel-to-serial shift register (74HC165)8K "Shoulders-of-Giants"...
In this chapter I will show you the main features of Raspberry Pi 3B+, Qwiic pHAT module and AS7262 sensor. Also we learn how to setup the Raspberry Pi and how to detect the peripheral of the sensor. Raspberry Pi 3B+ The Raspberry Pi 3 B+ provides you...