Z80 in a surface mount package, as found in the MVS and CD hardware.
The Z80 is an 8-bit little-endian CPU designed by Zilog.
All NeoGeo systems use it to handle "tracker music" playback. It runs at 4MHz and only has access to the YM2610, M1 ROM or Z80 files, and its own RAM.
See 68k/Z80 communication.
Since it doesn't share a RAM area with the 68k CPU like on the Sega Genesis, it can't be used efficiently to perform gameplay-related tasks.
See Z80 memory map and Z80 port map.
Z80 in DIP package, as found on AES boards.
Official Z8400 datasheet: []