MCFG_UPD7201_ADD("upd7201", XTAL_2_5MHz, 0, 0, 0, 0) // 2.5 Mhz from schematics
MCFG_Z80SIO_OUT_INT_CB(WRITELINE(rainbow_state, mpsc_irq))
MCFG_Z80SIO_OUT_TXDA_CB(DEVWRITELINE("rs232_a", rs232_port_device, write_txd))
MCFG_Z80SIO_OUT_TXDB_CB(DEVWRITELINE("rs232_b", rs232_port_device, write_txd))