The 6509 Datasheet is the key to understanding the inner workings of the enhanced processor that powered some versions of the Commodore 64, particularly those in Europe. Unlike the more common 6510, the 6509 offered crucial improvements, most notably expanded memory addressing capabilities. This allowed the C64 to break the 64KB memory barrier, though in a somewhat unconventional way. The 6509 Datasheet details these features, and others, to allow developers to better interact with the machine.
Decoding the 6509 Datasheet The Blueprint of Memory Expansion
The 6509 Datasheet is a technical document providing detailed specifications and information about the 6509 microprocessor. It outlines the chip’s architecture, pin configurations, instruction set, electrical characteristics, and timing diagrams. Essentially, it’s the comprehensive guide that hardware engineers and software developers used to understand how the 6509 operates and how to interface with it effectively. Without the 6509 Datasheet, understanding the memory addressing specifics would be next to impossible, along with certain operational characteristics.
The primary purpose of the 6509 Datasheet, from a developer’s perspective, was to enable the creation of software and hardware that could take advantage of the processor’s capabilities. This was especially important for accessing the additional memory available on systems like the Commodore 128, which used the 6509. Understanding the memory map, interrupt handling, and other low-level details was crucial for writing efficient and reliable programs. The extended memory addressing was not directly available to BASIC programmers, but assembler programmers were able to take advantage of it.
- Pin Diagram
- Electrical Specifications
- Instruction Set
- Memory Addressing Modes
The 6509’s ability to address more than 64KB of RAM (up to 1MB) through memory bank switching was its most significant enhancement. This feature unlocked the potential for more complex and data-intensive applications. This functionality wasn’t directly accessible through standard BASIC commands, requiring assembly language programming to truly leverage its power. Here’s a simplified view of the memory bank selection:
| Bank Select Bits | Memory Bank |
|---|---|
| 00 | Bank 0 |
| 01 | Bank 1 |
| 10 | Bank 2 |
| 11 | Bank 3 |
To gain an even more thorough understanding of the 6509’s specifications and intricacies, we suggest that you examine the source 6509 Datasheet itself.