MOS Technology 6509

The MOS Technology 6509, an enhanced version of the popular 6502 microprocessor, was capable of addressing up to 1 megabyte of RAM via bank switching. While numerous 6502-based processors could do bank switching, they did this via separate logic. The 6509 had this logic on-chip.

The 6509 had a reputation for being difficult to program, due to its bank switching scheme, and never fared well. It was used in the ill-fated Commodore CBM-II line of computers.

External links

MOS 6509 datasheet (GIF format, zipped)

65xx-series CPUs from MOS Technology, second source/clone vendors, and the Western Design Center

MOS 6501 MOS 6502 WDC 65C02 Hudson HuC6280 Ricoh 2A03 MOS 6507 MOS 6508 MOS 6509 MOS 6510 (and 7501, 8500, 8501) MOS 8502 CSG 65CE02 (and 4510) WDC 65802 WDC 65816 Ricoh 5A22 Nintendo SA-1 Renesas 740 family