The VME64S core is a VME slave controller with a synchronous local bus interface. It supports the VMEbus according to ANSI/VITA 1-1994. The core is designed to simplify creation of custom VME slave cards, either for new systems, or as a replacement for obsolete chips. A16/A24/A32 address mode, D8/D16/D32 data modes (read/write/read-modify-write), D16-BLT, D32-BLT, D64-MBLT block transfer cycles, and D8/D16/D32 interrupt acknowledge cycles are supported. Dedicated top-levels are available for D16 or D32 implementations with different address width support.