Introduction to the COSMAC 1802 Addition Instructions There are four COSMAC 1802 Addition Instructions: ADD, ADI, ADC, and ADCI. In this section we’ll take a closer look at each one of these instructions. Basically, the ADD statement will add a memory location to the value in the accumulator. The ADI Read More »
Introduction to the COSMAC 1802 Store Instructions The COSMAC 1802 Store Instructions allow us to store data to memory from the accumulator. We’ll discuss the different types of store instructions, and how they operate. You only have two store instructions, the STR (Store), and STXD (Store and Decrement). You can, Read More »
Introduction to COSMAC 1802 Load Instructions The COSMAC 1802 Load Instructions are probably the most important instructions to understand in the COSMAC. The main register of the 1802 (COSMAC) processor is the “D” register. Effectively, we know this as the “Accumulator”. We might load data into the accumulator and manipulate Read More »
Introduction to COSMAC UART Communication I’ll be using the CDP1802 Microprocessor kit to demonstrate COSMAC UART Communication. This setup uses the INS8250 chip for communication. The monitor initializes the IC. In this section, we’ll be sending data out of the serial port. UART is short for Universal Asynchronous Receive and Read More »
Introduction to the COSMAC Processor Stack Operation The COSMAC Processor Stack Operation will allow us to store data on the fly that we need to retrieve later. This will usually be an address contained in a register. Examples would be a program counter, or a memory location that contains data Read More »
Introduction to the COSMAC LED Display Timer For this post, I used the CDP1802 Microprocessor kit. The 1802 processor was on several space missions. This includes Gallileo craft which explored Jupiter. This kit has several nice features for learning purposes. It has an LED display, and you can add an Read More »
Introduction to the COSMAC CDP1802 LED Display Counter The COSMAC CDP1802 LED Display is a six segment display on the CDP1802 Microprocessor kit. Your kit also has a place to add an LCD display as well, however, I like the appearance of the LED display. In order to use this Read More »
Introduction to the COSMAC 1802 LCD Timer In this section, we’ll build a COSMAC 1802 LCD Timer. I’m using the CDP1802 Microprocessor kit for this with an LCD display. The code will also display the value of the timer (up to 255) on the LED indicators. Basically, to run the Read More »
Introduction to COSMAC 1802 Flasher Logic In this section, we’ll write a simple program for a COSMAC 1802 Flasher. We’ll keep this as simple as possible, and use a couple delay loops. In this case, we’ll just use the Q output of the processor. The most important commands for this Read More »
Introduction to the A18 Assembler for COSMAC The A18 Assembler for COSMAC will convert your COSMAC assembly programs to object code. After that, you can send the file to your processor. I’m using Debian 11 for this example, but the A18 package also comes with a .exe file if you Read More »
