Vintage Computers


Kim-1 Scan Based Timer

Introduction to the Kim-1 Scan Based Timer In this post, I’ll cover some code I wrote for a Kim-1 Scan Based Timer. You can calibrate this timer by changing the number of loops, or by adding NOP instructions to get it just right for your application. I put this timer Read More »

Kim-1 (UNO) Scan Timer

Imsai 8080 Replica Build

Introduction to the Imsai 8080 Replica Build The Imsai 8080 Replica Build went very smoothly. I’ve always wanted one of these units. The quality of the parts were very good, and I have to say the pictures you see do not do it justice. It’s best to see one in Read More »

IMSAI 8080 Replica Build

Kenbak-1 Relative Jumps

Introduction to Kenbak-1 Relative Jumps Kenbak-1 Relative Jumps will jump to a location relative to the program counter. Really, there is no relative jump instruction. Therefore, if we require a relative jump we will do this with the JPI (Indirect Jump) instruction. The advantage of relative jumps is that we Read More »

Kenbak-1 Relative Jumps

Kenbak-1 Two Byte Addition

Introduction to Kenbak-1 Two Byte Addition With the Kenbak-1 Two Byte Addition, we can add larger numbers. Keep in mind that with 8 bit addition, we can only have numbers up to 377 octal (255 decimal). That’s if we don’t even used signed values. This is very limiting. When we Read More »

Kenbak-1 Two Byte Addition

Programming Loops on the Kenbak-1

Introduction to Programming Loops on the Kenbak-1 When Programming Loops on the Kenbak-1, we will use the JPD instruction. Basically, we set a register to a specific value. For this example, we’ll use the X register. Every time our loop executes, we decrement the X register. When the X register Read More »

Kenbak-1 building loops

Kenbak-1 Division

Introduction to Kenbak-1 Division We’ll need to come up with a creative way to do Kenbak-1 Division. The Kenbak-1 does not have a way to divide directly by using instructions. We’ll simply need to do the division manually. Basically, the method I’ll use for this is to simply keep extracting Read More »

Kenbak-1 Division

Kenbak-1 Multiplication

Introduction to Kenbak-1 Multiplication Kenbak-1 Multiplication involves creating loops. Being designed in 1971, the Kenbak-1 has a limited instruction set. That limited instruction set presents some good challenges. These challenges force us not only to understand the Kenbak-1 itself, but also understand more about mathematics. There is no direct instruction Read More »

Multiplication on the Kenbak-1

Kenbak-1 Bitwise Instructions

Introduction to Kenbak-1 Bitwise Instructions The Kenbak-1 Bitwise instructions include AND, OR, and LNEG. With these instructions, think of the individual bits within an 8 bit word. With “AND”, a particular bit must be high in both the source and compare words to get the value of 1 in the Read More »

Kenbak-1 XOR Operation

Kenbak-1 Switch Number to Binary

Converting a Kenbak-1 Switch Number to Binary In this section, we’ll be converting a Kenbak-1 Switch Number to Binary. This project is a good example of the Right Shift on the Kenbak-1. Basically, when the user presses a number, we’ll display the binary bit pattern for that switch number. Mr. Read More »

Kenbak-1 Convert Switch Number to Octal

Configure Minicom for Kim-1 (Uno)

How to Configure Minicom for Kim-1 (Uno) To Configure Minicom for the Kim-1 (Uno), there are a few parameters we will want to set. Once you set up everything properly, you should have no problem connecting to and enjoying the Kim-1 Uno! Without proper configuration, though, your experience will quickly Read More »

Configure Minicom for Kim-1 (Uno)