MSXs have generally a Z80A when it is not integrated in a chipset. A is the CPU class for a frequency up to 4Mhz.

The MSX specification specifies a Z80A running at 3.58MHz. (More exactly 315/88 million Hz). The Z80 was originally designed by Zilog but most MSX have a Z80 from another manufacturer.

A few variations exist:

• Panasonic MSX2+ computers which can be switched programmatically to a higher CPU speed (5.36MHz)
• Panasonic Turbo R computers which also have a R800 CPU in addition to the Z80A
• Victor HC-90 and HC-95 computers which have a Z180 CPU in addition to the Z80A

Also, some systems feature a "speed controller" slider which allows the CPU to be slowed down (for use in games). This doesn't affect the CPU clock though. It's implemented as an autofire that actuates on the PAUSE button, synced with BLANK.

See this page for info about programming.

List of compatible Z80 found in the MSXs

• Zilog Z8400APS is one version from the original developer.
• GS Z8400A PS or GSS Z8400A PS (mainly MSXs made in Korean) (Goldstar)
• NEC D780C-1
• Rohm BU18400A-PS
• Sharp LH0080A
• SGS Z8400AB1 or ST Z8400AB1 (STMicroelectronics)

List of other compatible Z80

• Mostek MK3880