Introduction to the COSMAC 1802 Register Layout The COSMAC 1802 Register Layout is a bit different from other processors. If you are used to the 6502, for example, you will find the addressing is much more indirect. For example, the P register is not the program counter. It simply points Read More »
Introduction to Geoff Graham’s VT100 Terminal Geoff Graham’s VT100 Terminal is a hardware emulator. This is a simple board that you can build yourself for a very reasonable price. I purchased a pre-built module on Ebay. There are several versions of this board. For instance, you can use a configuration Read More »
Introduction to Wiring any Logic using only NAND Gates I’ve heard people say before that you can hard wire any logic using only NAND Gates. I started researching this a little bit, and purchased some NAND gate IC’s (74HC00). In this post, we’ll see how we would wire AND, OR, Read More »
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. I’ll be using the Kim UNO for this post. You may have to modify the program for your own use. You can calibrate this timer by changing the Read More »
Introduction to the ControlLogix Watch Window The ControlLogix Watch Window allows you to monitor tags from the current routine. You can also create a custom “Quick Watch” window to monitor any tag in the processor as you monitor the routine’s latter logic. This is very helpful when troubleshooting. Especially when Read More »
Introduction to ControlLogix Processor Status Flags ControlLogix Processor Status Flags will tell us when certain events occur during our instruction execution. In this section, we’ll discuss the purpose of each of these status flags, and how we might use them in our logic. It’s important to realize that you will Read More »
Resolving ControlLogix I/O Not Responding If you have ControlLogix I/O Not Responding, you will have a blinking green I/O light on the processor. Additionally, while you are online, you will see “I/O Not Responding” in the online toolbar. The newer processors have an alphanumeric display which could give you some Read More »
Solving when a ControlLogix Rung is True but No Output It’s frustrating when a ControlLogix Rung True but you have No Output. In this section we’ll go over the causes for this, and how to correct them. It’s important that the processor is just doing what it’s told. We just Read More »
Introduction to ControlLogix Branching in Ladder Logic ControlLogix Branching in Ladder Logic allows us to create “OR” Statements. Sometimes getting a branch on the right place in a rung is tricky for beginners. In this post, we’ll take a closer look at branching, We’ll discuss different ways to set up Read More »
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 »
