Inside the Macintosh: the memory.

Let's start from this post with a series of posts with technical "dissection" of the different areas of the Macintosh mainboard. It's very important to understand how the hardware works.Of course, a software emulator works differently from the real hardware, and many times it's a question of implementing tricks, especially when the emulator must run on a limited system such as a microcontroller.So I will take my time in studying components, I will...

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An experiment just for fun.

 I knew that "Digital" would enchant me. Especially for the fact that it gives me the opportunity to virtually replicate different areas of the Macintosh circuit to perform tests and understand how it works. Now I would like to do an experiment. In truth, I don't need to go so low level for the emulator I have to write, but I'm curious to see how far this circuit simulator goes. I want to try to implement the 64k-bit MT4264 DRAM memory...

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Bricks for this project, really?

I don't know if it's happened to you too, but when I study electronic diagrams it makes me want to "reconstruct" the circuit to see it work. It's as if your head starts to go faster in imagining that you already have all the components at hand, ready to be inserted into their respective sockets on the PCB. It is also frustrating to note that the transition from a scheme to a prototype is not so immediate, especially in my current condition, where...

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Diving deep in the Mac.

I've been diving online for days looking for technical information on the Apple Macintosh 128k hardware. In truth, I didn't find much, at least what I was looking for.I was studying the diagrams and photos of the motherboard that I found, and I understood that the "custom" chips have a crucial role in the functioning of the Mac. They are called "PAL", or "Programmable Array Logic", and are programmed from the factory with particular programs...

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Know the hardware.

What we need also is a schematic of the mainboard of the Macintosh 128k, and a photo of the PCB, top and bottom side. I think that if I dig into the hardware I could learn more, and the development process should be a bit easier.Unfortunately, ChatGPT can't help me find those on the Internet, so I did it by myself. It has been difficult to find them but in the end, I have found something usefu...

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Where to start from.

Now that I've set an environment for the development of tests that I can share with you, I am going back to the emulator My first idea is to design a main section based on a Finite State Machine, that is executed every cycle of the host application. In my Replit project this application is the SDL based environment, while in the STM32 board is a specific H7 targeted project. I would like to develop this emulator as a scalable and portable application...

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Code sharing, such a great idea.

Difficulties can't stop me, maybe they delay my results but my strong will helps me to find out a way to get things done. I had to stop for a couple of days, I had to go through several things, but I got an idea for this blog, and some enthusiasm made me get back on this track.What if I can show you the working source code or the entire emulator? Wouldn't it be great to show directly inside a post a working part of the code? That's a real possibility...

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