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mm5837: unify implementations
* create base mm5837_source device to provide raw output * mm5837_device is based on it * mm5837_stream_device generates a sound stream from it * frequency calculation now computed instead of table-based
This commit is contained in:
Aaron Giles
parent
7e2d6aa41e
commit
dfa1168970
@ -12,22 +12,16 @@
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#include "mm5837.h"
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//**************************************************************************
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// CONSTEXPR DEFINITIONS
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//**************************************************************************
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constexpr int mm5837_device::m_frequency[];
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//**************************************************************************
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// DEVICE DEFINITIONS
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//**************************************************************************
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DEFINE_DEVICE_TYPE(MM5837, mm5837_device, "mm5837", "MM5837 Digital Noise Source")
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DEFINE_DEVICE_TYPE(MM5837_STREAM, mm5837_stream_device, "mm5837", "MM5837 Digital Noise Stream")
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//**************************************************************************
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// LIVE DEVICE
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// MM5837 DEVICE
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//**************************************************************************
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//-------------------------------------------------
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@ -37,12 +31,12 @@ DEFINE_DEVICE_TYPE(MM5837, mm5837_device, "mm5837", "MM5837 Digital Noise Source
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mm5837_device::mm5837_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
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device_t(mconfig, MM5837, tag, owner, clock),
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m_output_cb(*this),
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m_vdd(0),
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m_timer(nullptr),
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m_shift(0)
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m_vdd(-12)
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{
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}
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//-------------------------------------------------
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// device_start - device-specific startup
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//-------------------------------------------------
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@ -56,36 +50,70 @@ void mm5837_device::device_start()
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m_timer = timer_alloc(0);
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// register for save states
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save_item(NAME(m_shift));
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save_item(NAME(m_source.m_shift));
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}
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//-------------------------------------------------
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// device_reset - device-specific reset
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//-------------------------------------------------
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void mm5837_device::device_reset()
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{
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// initialize with something
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m_shift = 123456;
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m_source.reset();
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if (m_vdd < 16)
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m_timer->adjust(attotime::zero, 0, attotime::from_hz(m_frequency[m_vdd]));
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m_timer->adjust(attotime::zero, 0, attotime::from_hz(mm5837_source::frequency(m_vdd)));
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else
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throw emu_fatalerror("%s: Invalid voltage: %d\n", tag(), m_vdd);
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}
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//-------------------------------------------------
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// device_timer - handle timer callbacks
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//-------------------------------------------------
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void mm5837_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
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{
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int tap_14 = BIT(m_shift, 13);
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int tap_17 = BIT(m_shift, 16);
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int zero = (m_shift == 0) ? 1 : 0;
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m_shift <<= 1;
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m_shift |= tap_14 ^ tap_17 ^ zero;
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m_output_cb(BIT(m_shift, 16));
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m_output_cb(m_source.clock());
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}
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//**************************************************************************
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// MM5837 STREAM DEVICE
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//**************************************************************************
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//-------------------------------------------------
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// mm5837_stream_device - constructor
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//-------------------------------------------------
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mm5837_stream_device::mm5837_stream_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
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device_t(mconfig, MM5837_STREAM, tag, owner, clock),
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device_sound_interface(mconfig, *this),
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m_stream(nullptr),
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m_vdd(-12)
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{
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}
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//-------------------------------------------------
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// device_start - device-specific startup
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//-------------------------------------------------
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void mm5837_stream_device::device_start()
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{
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m_stream = stream_alloc(0, 1, mm5837_source::frequency(m_vdd));
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save_item(NAME(m_source.m_shift));
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}
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//-------------------------------------------------
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// sound_stream_update - fill the sound buffer
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//-------------------------------------------------
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void mm5837_stream_device::sound_stream_update(sound_stream &stream, std::vector<read_stream_view> const &inputs, std::vector<write_stream_view> &outputs)
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{
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for (int sampindex = 0; sampindex < outputs[0].samples(); sampindex++)
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outputs[0].put(sampindex, m_source.clock() ? 1.0 : 0.0);
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}
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@ -94,6 +94,66 @@
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// TYPE DEFINITIONS
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//**************************************************************************
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// ======================> mm5837_source
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class mm5837_source
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{
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public:
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// construction/destruction
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mm5837_source() :
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m_shift(0x1ffff)
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{
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}
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// reset to base state
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void reset()
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{
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m_shift = 0x1ffff;
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}
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// clock one time and return the shift value
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u8 clock()
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{
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int tap_14 = BIT(m_shift, 13);
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int tap_17 = BIT(m_shift, 16);
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int zero = (m_shift == 0) ? 1 : 0;
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m_shift <<= 1;
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m_shift |= tap_14 ^ tap_17 ^ zero;
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return BIT(m_shift, 16);
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}
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// taken from the book 'mims circuit scrapbook, vol. 1'
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static u32 frequency(double vdd)
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{
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// Vdd should be negative -6.2..-15V
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if (vdd > -6.2 || vdd < -15)
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throw emu_fatalerror("mm5837 frequency should be -6.2V .. -15V");
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// curve fitting done in excel from this table:
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// { 0, 0, 0, 0, 0, 0, 1, 2267, 8731, 16382, 23531, 32564, 38347, 40010, 37800, 33173 }
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double result = 191.98*vdd*vdd*vdd + 5448.4*vdd*vdd + 43388*vdd + 105347;
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// datasheet claims frequency range 24-56kHz at Vdd=-14V, but also lists
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// maximum cycle times as ranging from 1.1-2.4s; since the 17-bit shift
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// register cycles after 131072 clocks, we would expect the actual cycle
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// times to be 2.34-5.46s at the 24-56kHz frequency range, so I'm presuming
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// that it ticks 2x per "clock", effectively running at 2x the frequency
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result *= 2;
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// make sure the result isn't TOO crazy
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result = std::max(result, 100.0);
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return u32(result);
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}
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// leave this public for easy saving
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u32 m_shift;
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};
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// ======================> mm5837_device
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class mm5837_device : public device_t
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{
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public:
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@ -101,7 +161,7 @@ public:
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mm5837_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock = 0);
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// configuration
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void set_vdd_voltage(int voltage) { m_vdd = voltage; }
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void set_vdd(double voltage) { m_vdd = voltage; }
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auto output_callback() { return m_output_cb.bind(); }
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protected:
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@ -111,24 +171,42 @@ protected:
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virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) override;
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private:
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// taken from the book 'mims circuit scrapbook, vol. 1'
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// this is the frequency the chip runs at when given a vdd voltage of -0 to -15
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static constexpr int m_frequency[16] = { 0, 0, 0, 0, 0, 0, 1, 2267, 8731, 16382, 23531, 32564, 38347, 40010, 37800, 33173 };
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// callbacks
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devcb_write_line m_output_cb;
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// voltage (as positive number)
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int m_vdd;
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// output timer
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emu_timer *m_timer;
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// state
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uint32_t m_shift;
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// internal state
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devcb_write_line m_output_cb; // output callback
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emu_timer *m_timer; // output timer
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double m_vdd; // configured voltage
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mm5837_source m_source; // noise source
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};
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// device type definition
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// ======================> mm5837_stream_device
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class mm5837_stream_device : public device_t, public device_sound_interface
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{
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public:
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// construction/destruction
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mm5837_stream_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
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// configuration
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void set_vdd(double voltage) { m_vdd = voltage; }
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protected:
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// device-level overrides
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virtual void device_start() override;
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// sound stream update overrides
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virtual void sound_stream_update(sound_stream &stream, std::vector<read_stream_view> const &inputs, std::vector<write_stream_view> &outputs) override;
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private:
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sound_stream *m_stream; // sound stream
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double m_vdd; // configured voltage
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mm5837_source m_source; // noise source
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};
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// device type definitions
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DECLARE_DEVICE_TYPE(MM5837, mm5837_device)
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DECLARE_DEVICE_TYPE(MM5837_STREAM, mm5837_stream_device)
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#endif // MAME_SOUND_MM5837_H
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@ -55,6 +55,7 @@
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***************************************************************************/
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#include "emu.h"
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#include "sound/mm5837.h"
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#include "audio/sente6vb.h"
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#include "cpu/z80/z80.h"
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#include "machine/clock.h"
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@ -66,53 +67,6 @@
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DEFINE_DEVICE_TYPE(SENTE6VB, sente6vb_device, "sente6vb", "Bally Sente 6VB Audio Board")
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/*************************************
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*
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* Trivial sound device to spew
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* a MM5837 noise stream to CEM3394
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* inputs
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*
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*************************************/
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DECLARE_DEVICE_TYPE(MM5837_NOISE_SOURCE, mm5837_noise_source)
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class mm5837_noise_source : public device_t, public device_sound_interface
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{
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public:
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mm5837_noise_source(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
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device_t(mconfig, MM5837_NOISE_SOURCE, tag, owner, clock),
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device_sound_interface(mconfig, *this),
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m_stream(nullptr),
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m_noise_state(0x1ffff)
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{
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}
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protected:
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// device-level overrides
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virtual void device_start() override
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{
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m_stream = stream_alloc(0, 1, clock());
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save_item(NAME(m_noise_state));
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}
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// sound stream update overrides
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virtual void sound_stream_update(sound_stream &stream, std::vector<read_stream_view> const &inputs, std::vector<write_stream_view> &outputs) override
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{
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for (int sampindex = 0; sampindex < outputs[0].samples(); sampindex++)
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{
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outputs[0].put(sampindex, BIT(m_noise_state, 0) ? 1.0 : 0.0);
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m_noise_state = (m_noise_state >> 1) | ((BIT(m_noise_state, 0) ^ BIT(m_noise_state, 3)) << 16);
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}
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}
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private:
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sound_stream *m_stream; // sound stream
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u32 m_noise_state; // noise state
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};
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DEFINE_DEVICE_TYPE(MM5837_NOISE_SOURCE, mm5837_noise_source, "mm5837noise", "MM5837")
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/*************************************
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*
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@ -172,7 +126,9 @@ void sente6vb_device::device_add_mconfig(machine_config &config)
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SPEAKER(config, "mono").front_center();
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mm5837_noise_source &noise(MM5837_NOISE_SOURCE(config, "noise", 100000));
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mm5837_stream_device &noise(MM5837_STREAM(config, "noise", 0));
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// noise.set_vdd(-6.5); // seems too low -- possible the mapping in mm5837 is wrong
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noise.set_vdd(-8.0);
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for (auto &cem_device : m_cem_device)
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{
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@ -180,7 +136,7 @@ void sente6vb_device::device_add_mconfig(machine_config &config)
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cem_device->set_vco_zero_freq(431.894);
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cem_device->set_filter_zero_freq(1300.0);
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cem_device->add_route(ALL_OUTPUTS, "mono", 0.90);
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noise.add_route(0, *cem_device, 1.0);
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noise.add_route(0, *cem_device, 0.5);
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}
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}
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@ -554,7 +554,7 @@ void beezer_state::beezer(machine_config &config)
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// schematics show an input labeled VCO to channel 2, but the source is unknown
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mm5837_device &noise(MM5837(config, "noise"));
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noise.set_vdd_voltage(12);
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noise.set_vdd(-12);
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noise.output_callback().set(FUNC(beezer_state::noise_w));
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SPEAKER(config, "speaker").front_center();
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