void s4_state::s4a(machine_config &config) { s4(config); /* Add the soundcard */ M6808(config, m_audiocpu, 3580000); m_audiocpu->set_addrmap(AS_PROGRAM, &s4_state::s4_audio_map); MCFG_MACHINE_RESET_OVERRIDE(s4_state, s4a) SPEAKER(config, "speaker").front_center(); MC1408(config, "dac", 0).add_route(ALL_OUTPUTS, "speaker", 0.5); voltage_regulator_device &vref(VOLTAGE_REGULATOR(config, "vref")); vref.add_route(0, "dac", 1.0, DAC_VREF_POS_INPUT); vref.add_route(0, "dac", -1.0, DAC_VREF_NEG_INPUT); PIA6821(config, m_pias, 0); m_pias->readpb_handler().set(FUNC(s4_state::sound_r)); m_pias->writepa_handler().set("dac", FUNC(dac_byte_interface::data_w)); m_pias->irqa_handler().set_inputline("audiocpu", M6808_IRQ_LINE); m_pias->irqb_handler().set_inputline("audiocpu", M6808_IRQ_LINE); }