No such thing as rw. You have to split it up. .r(blah).w(foo); Hi , thank you Robert In PGM driver: https://github.com/mamedev/mame/blob/master/src/mame/drivers/pgm.cpp there is: line 339: map(0xc08000, 0xc08001).portr("P1P2"); line 340: map(0xc08002, 0xc08003).portr("P3P4"); If...