MOS Technology 6510

Pin configuration

The MOS Technology 6510 is an 8- bit - microprocessor from MOS Technology, Inc. , which in 1982 came on the market. Due to its simplicity and, above all, the very low price compared to the established Intel and Motorola processors with high performance, it was installed in the home computer Commodore 64 and the 5¼ inch VC1551 floppy disk drive . The internal processor architecture is almost identical to that of the MOS 6502 microprocessor - in particular, the instruction set is upwardly compatible, a program that was written for the 6502 also runs without modification on a 6510 processor. The processor was operated with clock frequencies between 20 kHz and 2 MHz and had a 16-bit address bus and an 8-bit data bus .

The main changes compared to the 6502 were the new 8-bit I / O ports (only six I / O pins were available in the most common version of the 6510), and the address bus can also be operated in tri-state mode. The 6510 was only used in the Commodore 64 and its variants. In the C64, the additional I / O pins of the processor were used to switch the computer's memory map through bank switching and also to control three of the four signal lines of the datassette .

The CPU is fully compatible with the 6502 processor with regard to opcodes , even with regard to all mask errors and illegal opcodes (opcode matrix).

variants

MOS 8500

In 1985 MOS Technology produced the 8500 , an HMOS version of the 6510 processor, it is practically identical to the NMOS version of the 6510. The 8500 was originally developed for use in the modernized C64, the C64C model. However, in 1985 limited quantities of 8500 processors were found on older NMOS-based C64s. It made its official debut in 1987 in a motherboard with the new 85xx HMOS chipset.

MOS 7501/8501

The 7501/8501 variant of the 6510 was introduced in 1984. The processor was installed in the C16 , C116 and Plus / 4 Commodore models, where its I / O port was not only used to control the datasette , but also for the CBM bus . The main difference between 7501 and 8501 CPUs is that they were made with different technologies: the 7501 was made with HMOS-1 technologies , the 8501 with HMOS-2 technologies. The NMI (unmasked interrupt) signal was not possible for the MOS 7501 and MOS 8501.

MOS 8502

The 2 MHz variant MOS Technology 8502 was used in the Commodore 128 ; the processor was opcode compatible (including the undocumented illegal opcodes).