Press ''Scroll Lock'' to toggle partial keyboard emulation mode. Now you can use ''P'' to pause MAME, ''Tab'' to enter the MAME menu, and ''Escape'' to quit MAME. ''Alt-Return'' toggles fullscreen mode.
You can use the "-ab" commandline option to type text into MAME, e.g.
mame cpc6128 -flop1 disk.dsk -ab "run\"disc\n"
will boot the disc.
===Device options for the CPC from [http://www.progettoemma.net/mess/extra.html sysinfo.dat]===