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);
}
