diff options
author | 2016-12-12 01:07:45 +0100 | |
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committer | 2016-12-12 01:08:29 +0100 | |
commit | 92ce7cd13c68c063b1b03d1f7f7c6dac4f77dd4e (patch) | |
tree | b6438472344884b46d2ebf133dd47f6f741e98ad /src/devices/sound/dac76.cpp | |
parent | a5729bb5d971527f4e36c076553a2600a188397d (diff) |
beezer: Rewrite driver
- Uses the standard 6840 PTM core for sound generation
- New MM583 Noise Generator device
- New DAC-76 DAC sound
- Use resistor network values for colors
- Use bankdev device for banking
Diffstat (limited to 'src/devices/sound/dac76.cpp')
-rw-r--r-- | src/devices/sound/dac76.cpp | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/devices/sound/dac76.cpp b/src/devices/sound/dac76.cpp new file mode 100644 index 00000000000..965b74473e6 --- /dev/null +++ b/src/devices/sound/dac76.cpp @@ -0,0 +1,91 @@ +// license: GPL-2.0+ +// copyright-holders: Dirk Best +/*************************************************************************** + + PMI DAC-76 COMDAC + + Companding D/A Converter + +***************************************************************************/ + +#include "dac76.h" + + +//************************************************************************** +// CONSTEXPR DEFINITIONS +//************************************************************************** + +constexpr int dac76_device::m_level[]; + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +const device_type DAC76 = &device_creator<dac76_device>; + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// dac76_device - constructor +//------------------------------------------------- + +dac76_device::dac76_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) : + device_t(mconfig, DAC76, "DAC-76 COMDAC", tag, owner, clock, "dac76", __FILE__), + device_sound_interface(mconfig, *this), + m_stream(nullptr), + m_chord(0), + m_step(0), + m_sb(false) +{ +} + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void dac76_device::device_start() +{ + // create sound stream + m_stream = machine().sound().stream_alloc(*this, 0, 1, machine().sample_rate() * 8); + + // register for save states + save_item(NAME(m_chord)); + save_item(NAME(m_step)); + save_item(NAME(m_sb)); +} + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void dac76_device::device_reset() +{ + m_chord = 0; + m_step = 0; + m_sb = false; +} + +//------------------------------------------------- +// sound_stream_update - handle update requests for +// our sound stream +//------------------------------------------------- + +void dac76_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) +{ + // get current output level + int step_size = (2 << m_chord); + stream_sample_t vout = m_level[m_chord] + m_step * step_size; + + // apply sign bit + vout *= (m_sb ? +1 : -1); + + // range is 0-8031, normalize to about 0-32768 range + vout *= 4; + + for (int i = 0; i < samples; i++) + outputs[0][i] = vout; +} |