Or you can try the new z80sio where I have added the upd7201 support recently, or did I ask you to do that already? smile

Code
#include "machine/z80sio.h" // instead of z80dart.h


Code
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))