65C816 vs. 68000

Attribute	65C816	68000
Manufacturer	WDC	Motorola
Architecture	CISC	CISC
Instruction Set	16-bit/8-bit	16-bit
Registers	8 general purpose	8 data, 7 address
Addressing Modes	9	7
Speed	Up to 14 MHz	Up to 12.5 MHz

Introduction

When it comes to choosing a processor for a project, developers often have to weigh the pros and cons of different options. Two popular choices in the realm of embedded systems are the 65C816 and the 68000 processors. Both processors have their own unique attributes that make them suitable for different applications. In this article, we will compare the key features of the 65C816 and 68000 processors to help you make an informed decision.

Architecture

The 65C816 processor is an enhanced version of the 6502 processor, featuring a 16-bit data bus and a 24-bit address bus. This allows it to address up to 16MB of memory. On the other hand, the 68000 processor is a 32-bit processor with a 32-bit data bus and a 24-bit address bus, capable of addressing up to 16MB of memory. The 68000 processor also has a more complex instruction set compared to the 65C816, making it more suitable for high-performance applications.

Performance

When it comes to performance, the 68000 processor has the upper hand due to its 32-bit architecture and more complex instruction set. It is capable of executing instructions faster than the 65C816 processor, making it ideal for applications that require high-speed processing. However, the 65C816 processor is no slouch either, especially when it comes to handling 8-bit operations. Its compatibility with the 6502 instruction set allows it to run legacy software efficiently.

Memory Management

Both the 65C816 and 68000 processors support memory management units (MMUs) for virtual memory management. The 68000 processor has a more advanced MMU compared to the 65C816, allowing for more efficient memory management and protection. This makes the 68000 processor a better choice for applications that require complex memory management schemes. On the other hand, the 65C816 processor's simpler MMU may be sufficient for applications that do not require advanced memory management features.

Peripheral Support

When it comes to peripheral support, the 68000 processor has a wider range of peripherals available compared to the 65C816. This is due to the popularity of the 68000 processor in the industry, leading to a larger ecosystem of peripherals and development tools. However, the 65C816 processor is not far behind, with a decent selection of peripherals available for embedded systems applications. Developers may need to consider the availability of peripherals when choosing between the two processors.

Cost

In terms of cost, the 65C816 processor is generally more affordable compared to the 68000 processor. This makes it a more attractive option for projects with budget constraints. However, the cost difference may be justified by the performance and features offered by the 68000 processor. Developers should consider their budget constraints and performance requirements when deciding between the two processors.

Conclusion

Both the 65C816 and 68000 processors have their own strengths and weaknesses, making them suitable for different applications. The 68000 processor offers superior performance and advanced features, making it ideal for high-performance applications. On the other hand, the 65C816 processor is more cost-effective and offers compatibility with legacy software. Ultimately, the choice between the two processors will depend on the specific requirements of the project and the budget constraints of the developer.