6804

The 6804 is a microcontroller developed by Motorola in the early 1980s, part of the Motorola 68000 family of processors. It was designed as a low-cost, single-chip solution for embedded applications, offering a balance between performance and cost. The 6804 is essentially a simplified version of the more powerful 6800 series, featuring a 16-bit architecture with a 16-bit address bus, allowing it to access up to 64KB of memory.

One of the key features of the 6804 is its integrated peripherals, including a programmable timer, serial communication interface, and a small amount of on-chip RAM. This integration reduced the need for external components, making it ideal for compact applications. The processor also supports a variety of addressing modes, enabling efficient memory access and code execution.

The 6804 was widely used in early personal computers, calculators, and industrial control systems. It was particularly popular in the 1980s due to its affordability and versatility. Despite its age, the 6804 remains a subject of interest among retro computing enthusiasts and hobbyists working on vintage projects. Its design influenced later microcontrollers and remains a benchmark for embedded systems engineering.

The instruction set of the 6804 is relatively straightforward, with a focus on basic arithmetic, logic, and data manipulation operations. It lacks some of the advanced features found in later 68000-based processors, such as floating-point support or advanced addressing modes, but it compensates with simplicity and efficiency for its intended use cases. The 6804’s design also laid the groundwork for Motorola’s subsequent microcontroller offerings, including the 68HC05 and 68HC11 series.