Getting SAP-py

You’ve probably heard me talk about this several times on the videos and on other posts on Facebook and the like, but I’ve not actually explained much about it. So the question is: What is this SAP thing I keep talking about making?

SAP is an acronym that stand for Simple As Possible. When applied to computing, it’s a machine that can perform basic arithmetic and also be programmable.

There’s a great book called Digital Computer Electronics by Dr Albert Paul Malvino. This book is basically what we are going to be covering throughout the SAP series. We’ll be looking into digital logic, building logic gates with transistors and then moving on to building three different SAP systems. They differ slightly with each increment of version. In short, here’s where I visualise the series going:

  1. We’ll start with number systems and converting those into each other. The only number systems we will be interested in are binary, decimal and hexadecimal.
  2. Logic Gates. We’ll be looking at basic logic gates and boolean algebra.
  3. Advanced logic gates. TWe’ll start taking a look at negated logic gates and exclusive gates.
  4. Transistor Logic. We’ll be getting practical with transistors to build all the logic gates we’ve looked at so far.
  5. Arithmetic in computing. Binary addition, binary subtraction, adders and 2’s complement all get explained here.
  6. Flip-Flops. Not the things you wear on your feet. At this point things are going to start gearing up towards SAPs…
  7. Registers & Counters. These play a major role in a computer system.
  8. Memory. RAM and ROM. PROM and EPROM. This will be the final part before we get on to:
  9. SAP-1: Whilst it only has 5 instructions, it can add and subtract 8-bit numbers. We’ll be learning about bus transfers and start looking at timing here as well.
  10. SAP-2: This one has 43 instructions and more registers than the SAP-1. Here’s where we start to think more closely about how we use the memory for our programs and jumping around in subroutines to create more complex programs and functions.
  11. SAP-3: Now we’re getting into the realms of microcontroller systems. The SAP-3 has indirect addressing and other features that crop up in early microprocessors such as the MOS6502 (widely known for its use in the NES, Atari 2600 and the Commodore 64). We won’t actually be building a games system, but the SAP-3 build will give us an insight into how stacks and other memory address techniques work. This one will be INCREDIBLY in-depth and will get to a nerdgasm level that’s deeper than anyhting that’s come before.

After that, we may start taking a look at microcontrollers such at the Microchip PIC and the Atmel AVR (commonly known as being the microcontroller of choice for the Arduino project).

Please let me know what you think of this idea as it will take a lot of my time to think, produce and create this series and I wouldn’t want to put all this effort and love into a subject only to find that no one is all that interested in it. 😉

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