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- ===========================================
- Sound Blaster Live mixer / default DSP code
- ===========================================
- The EMU10K1 chips have a DSP part which can be programmed to support
- various ways of sample processing, which is described here.
- (This article does not deal with the overall functionality of the
- EMU10K1 chips. See the manuals section for further details.)
- The ALSA driver programs this portion of chip by default code
- (can be altered later) which offers the following functionality:
- IEC958 (S/PDIF) raw PCM
- =======================
- This PCM device (it's the 4th PCM device (index 3!) and first subdevice
- (index 0) for a given card) allows to forward 48kHz, stereo, 16-bit
- little endian streams without any modifications to the digital output
- (coaxial or optical). The universal interface allows the creation of up
- to 8 raw PCM devices operating at 48kHz, 16-bit little endian. It would
- be easy to add support for multichannel devices to the current code,
- but the conversion routines exist only for stereo (2-channel streams)
- at the time.
- Look to tram_poke routines in lowlevel/emu10k1/emufx.c for more details.
- Digital mixer controls
- ======================
- These controls are built using the DSP instructions. They offer extended
- functionality. Only the default build-in code in the ALSA driver is described
- here. Note that the controls work as attenuators: the maximum value is the
- neutral position leaving the signal unchanged. Note that if the same destination
- is mentioned in multiple controls, the signal is accumulated and can be wrapped
- (set to maximal or minimal value without checking of overflow).
- Explanation of used abbreviations:
- DAC
- digital to analog converter
- ADC
- analog to digital converter
- I2S
- one-way three wire serial bus for digital sound by Philips Semiconductors
- (this standard is used for connecting standalone DAC and ADC converters)
- LFE
- low frequency effects (subwoofer signal)
- AC97
- a chip containing an analog mixer, DAC and ADC converters
- IEC958
- S/PDIF
- FX-bus
- the EMU10K1 chip has an effect bus containing 16 accumulators.
- Each of the synthesizer voices can feed its output to these accumulators
- and the DSP microcontroller can operate with the resulting sum.
- ``name='Wave Playback Volume',index=0``
- ---------------------------------------
- This control is used to attenuate samples for left and right PCM FX-bus
- accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples.
- The result samples are forwarded to the front DAC PCM slots of the AC97 codec.
- ``name='Wave Surround Playback Volume',index=0``
- ------------------------------------------------
- This control is used to attenuate samples for left and right PCM FX-bus
- accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples.
- The result samples are forwarded to the rear I2S DACs. These DACs operates
- separately (they are not inside the AC97 codec).
- ``name='Wave Center Playback Volume',index=0``
- ----------------------------------------------
- This control is used to attenuate samples for left and right PCM FX-bus
- accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples.
- The result is mixed to mono signal (single channel) and forwarded to
- the ??rear?? right DAC PCM slot of the AC97 codec.
- ``name='Wave LFE Playback Volume',index=0``
- -------------------------------------------
- This control is used to attenuate samples for left and right PCM FX-bus
- accumulators. ALSA uses accumulators 0 and 1 for left and right PCM.
- The result is mixed to mono signal (single channel) and forwarded to
- the ??rear?? left DAC PCM slot of the AC97 codec.
- ``name='Wave Capture Volume',index=0``, ``name='Wave Capture Switch',index=0``
- ------------------------------------------------------------------------------
- These controls are used to attenuate samples for left and right PCM FX-bus
- accumulator. ALSA uses accumulators 0 and 1 for left and right PCM.
- The result is forwarded to the ADC capture FIFO (thus to the standard capture
- PCM device).
- ``name='Synth Playback Volume',index=0``
- ----------------------------------------
- This control is used to attenuate samples for left and right MIDI FX-bus
- accumulators. ALSA uses accumulators 4 and 5 for left and right MIDI samples.
- The result samples are forwarded to the front DAC PCM slots of the AC97 codec.
- ``name='Synth Capture Volume',index=0``, ``name='Synth Capture Switch',index=0``
- --------------------------------------------------------------------------------
- These controls are used to attenuate samples for left and right MIDI FX-bus
- accumulator. ALSA uses accumulators 4 and 5 for left and right PCM.
- The result is forwarded to the ADC capture FIFO (thus to the standard capture
- PCM device).
- ``name='Surround Playback Volume',index=0``
- -------------------------------------------
- This control is used to attenuate samples for left and right rear PCM FX-bus
- accumulators. ALSA uses accumulators 2 and 3 for left and right rear PCM samples.
- The result samples are forwarded to the rear I2S DACs. These DACs operate
- separately (they are not inside the AC97 codec).
- ``name='Surround Capture Volume',index=0``, ``name='Surround Capture Switch',index=0``
- --------------------------------------------------------------------------------------
- These controls are used to attenuate samples for left and right rear PCM FX-bus
- accumulators. ALSA uses accumulators 2 and 3 for left and right rear PCM samples.
- The result is forwarded to the ADC capture FIFO (thus to the standard capture
- PCM device).
- ``name='Center Playback Volume',index=0``
- -----------------------------------------
- This control is used to attenuate sample for center PCM FX-bus accumulator.
- ALSA uses accumulator 6 for center PCM sample. The result sample is forwarded
- to the ??rear?? right DAC PCM slot of the AC97 codec.
- ``name='LFE Playback Volume',index=0``
- --------------------------------------
- This control is used to attenuate sample for center PCM FX-bus accumulator.
- ALSA uses accumulator 6 for center PCM sample. The result sample is forwarded
- to the ??rear?? left DAC PCM slot of the AC97 codec.
- ``name='AC97 Playback Volume',index=0``
- ---------------------------------------
- This control is used to attenuate samples for left and right front ADC PCM slots
- of the AC97 codec. The result samples are forwarded to the front DAC PCM
- slots of the AC97 codec.
- .. note::
- This control should be zero for the standard operations, otherwise
- a digital loopback is activated.
- ``name='AC97 Capture Volume',index=0``
- --------------------------------------
- This control is used to attenuate samples for left and right front ADC PCM slots
- of the AC97 codec. The result is forwarded to the ADC capture FIFO (thus to
- the standard capture PCM device).
- .. note::
- This control should be 100 (maximal value), otherwise no analog
- inputs of the AC97 codec can be captured (recorded).
- ``name='IEC958 TTL Playback Volume',index=0``
- ---------------------------------------------
- This control is used to attenuate samples from left and right IEC958 TTL
- digital inputs (usually used by a CDROM drive). The result samples are
- forwarded to the front DAC PCM slots of the AC97 codec.
- ``name='IEC958 TTL Capture Volume',index=0``
- --------------------------------------------
- This control is used to attenuate samples from left and right IEC958 TTL
- digital inputs (usually used by a CDROM drive). The result samples are
- forwarded to the ADC capture FIFO (thus to the standard capture PCM device).
- ``name='Zoom Video Playback Volume',index=0``
- ---------------------------------------------
- This control is used to attenuate samples from left and right zoom video
- digital inputs (usually used by a CDROM drive). The result samples are
- forwarded to the front DAC PCM slots of the AC97 codec.
- ``name='Zoom Video Capture Volume',index=0``
- --------------------------------------------
- This control is used to attenuate samples from left and right zoom video
- digital inputs (usually used by a CDROM drive). The result samples are
- forwarded to the ADC capture FIFO (thus to the standard capture PCM device).
- ``name='IEC958 LiveDrive Playback Volume',index=0``
- ---------------------------------------------------
- This control is used to attenuate samples from left and right IEC958 optical
- digital input. The result samples are forwarded to the front DAC PCM slots
- of the AC97 codec.
- ``name='IEC958 LiveDrive Capture Volume',index=0``
- --------------------------------------------------
- This control is used to attenuate samples from left and right IEC958 optical
- digital inputs. The result samples are forwarded to the ADC capture FIFO
- (thus to the standard capture PCM device).
- ``name='IEC958 Coaxial Playback Volume',index=0``
- -------------------------------------------------
- This control is used to attenuate samples from left and right IEC958 coaxial
- digital inputs. The result samples are forwarded to the front DAC PCM slots
- of the AC97 codec.
- ``name='IEC958 Coaxial Capture Volume',index=0``
- ------------------------------------------------
- This control is used to attenuate samples from left and right IEC958 coaxial
- digital inputs. The result samples are forwarded to the ADC capture FIFO
- (thus to the standard capture PCM device).
- ``name='Line LiveDrive Playback Volume',index=0``, ``name='Line LiveDrive Playback Volume',index=1``
- ----------------------------------------------------------------------------------------------------
- This control is used to attenuate samples from left and right I2S ADC
- inputs (on the LiveDrive). The result samples are forwarded to the front
- DAC PCM slots of the AC97 codec.
- ``name='Line LiveDrive Capture Volume',index=1``, ``name='Line LiveDrive Capture Volume',index=1``
- --------------------------------------------------------------------------------------------------
- This control is used to attenuate samples from left and right I2S ADC
- inputs (on the LiveDrive). The result samples are forwarded to the ADC
- capture FIFO (thus to the standard capture PCM device).
- ``name='Tone Control - Switch',index=0``
- ----------------------------------------
- This control turns the tone control on or off. The samples for front, rear
- and center / LFE outputs are affected.
- ``name='Tone Control - Bass',index=0``
- --------------------------------------
- This control sets the bass intensity. There is no neutral value!!
- When the tone control code is activated, the samples are always modified.
- The closest value to pure signal is 20.
- ``name='Tone Control - Treble',index=0``
- ----------------------------------------
- This control sets the treble intensity. There is no neutral value!!
- When the tone control code is activated, the samples are always modified.
- The closest value to pure signal is 20.
- ``name='IEC958 Optical Raw Playback Switch',index=0``
- -----------------------------------------------------
- If this switch is on, then the samples for the IEC958 (S/PDIF) digital
- output are taken only from the raw FX8010 PCM, otherwise standard front
- PCM samples are taken.
- ``name='Headphone Playback Volume',index=1``
- --------------------------------------------
- This control attenuates the samples for the headphone output.
- ``name='Headphone Center Playback Switch',index=1``
- ---------------------------------------------------
- If this switch is on, then the sample for the center PCM is put to the
- left headphone output (useful for SB Live cards without separate center/LFE
- output).
- ``name='Headphone LFE Playback Switch',index=1``
- ------------------------------------------------
- If this switch is on, then the sample for the center PCM is put to the
- right headphone output (useful for SB Live cards without separate center/LFE
- output).
- PCM stream related controls
- ===========================
- ``name='EMU10K1 PCM Volume',index 0-31``
- ----------------------------------------
- Channel volume attenuation in range 0-0xffff. The maximum value (no
- attenuation) is default. The channel mapping for three values is
- as follows:
- * 0 - mono, default 0xffff (no attenuation)
- * 1 - left, default 0xffff (no attenuation)
- * 2 - right, default 0xffff (no attenuation)
- ``name='EMU10K1 PCM Send Routing',index 0-31``
- ----------------------------------------------
- This control specifies the destination - FX-bus accumulators. There are
- twelve values with this mapping:
- * 0 - mono, A destination (FX-bus 0-15), default 0
- * 1 - mono, B destination (FX-bus 0-15), default 1
- * 2 - mono, C destination (FX-bus 0-15), default 2
- * 3 - mono, D destination (FX-bus 0-15), default 3
- * 4 - left, A destination (FX-bus 0-15), default 0
- * 5 - left, B destination (FX-bus 0-15), default 1
- * 6 - left, C destination (FX-bus 0-15), default 2
- * 7 - left, D destination (FX-bus 0-15), default 3
- * 8 - right, A destination (FX-bus 0-15), default 0
- * 9 - right, B destination (FX-bus 0-15), default 1
- * 10 - right, C destination (FX-bus 0-15), default 2
- * 11 - right, D destination (FX-bus 0-15), default 3
- Don't forget that it's illegal to assign a channel to the same FX-bus accumulator
- more than once (it means 0=0 && 1=0 is an invalid combination).
-
- ``name='EMU10K1 PCM Send Volume',index 0-31``
- ---------------------------------------------
- It specifies the attenuation (amount) for given destination in range 0-255.
- The channel mapping is following:
- * 0 - mono, A destination attn, default 255 (no attenuation)
- * 1 - mono, B destination attn, default 255 (no attenuation)
- * 2 - mono, C destination attn, default 0 (mute)
- * 3 - mono, D destination attn, default 0 (mute)
- * 4 - left, A destination attn, default 255 (no attenuation)
- * 5 - left, B destination attn, default 0 (mute)
- * 6 - left, C destination attn, default 0 (mute)
- * 7 - left, D destination attn, default 0 (mute)
- * 8 - right, A destination attn, default 0 (mute)
- * 9 - right, B destination attn, default 255 (no attenuation)
- * 10 - right, C destination attn, default 0 (mute)
- * 11 - right, D destination attn, default 0 (mute)
- MANUALS/PATENTS
- ===============
- ftp://opensource.creative.com/pub/doc
- -------------------------------------
- LM4545.pdf
- AC97 Codec
- m2049.pdf
- The EMU10K1 Digital Audio Processor
- hog63.ps
- FX8010 - A DSP Chip Architecture for Audio Effects
- WIPO Patents
- ------------
- WO 9901813 (A1)
- Audio Effects Processor with multiple asynchronous streams
- (Jan. 14, 1999)
- WO 9901814 (A1)
- Processor with Instruction Set for Audio Effects (Jan. 14, 1999)
- WO 9901953 (A1)
- Audio Effects Processor having Decoupled Instruction
- Execution and Audio Data Sequencing (Jan. 14, 1999)
- US Patents (https://www.uspto.gov/)
- -----------------------------------
- US 5925841
- Digital Sampling Instrument employing cache memory (Jul. 20, 1999)
- US 5928342
- Audio Effects Processor integrated on a single chip
- with a multiport memory onto which multiple asynchronous
- digital sound samples can be concurrently loaded
- (Jul. 27, 1999)
- US 5930158
- Processor with Instruction Set for Audio Effects (Jul. 27, 1999)
- US 6032235
- Memory initialization circuit (Tram) (Feb. 29, 2000)
- US 6138207
- Interpolation looping of audio samples in cache connected to
- system bus with prioritization and modification of bus transfers
- in accordance with loop ends and minimum block sizes
- (Oct. 24, 2000)
- US 6151670
- Method for conserving memory storage using a
- pool of short term memory registers
- (Nov. 21, 2000)
- US 6195715
- Interrupt control for multiple programs communicating with
- a common interrupt by associating programs to GP registers,
- defining interrupt register, polling GP registers, and invoking
- callback routine associated with defined interrupt register
- (Feb. 27, 2001)
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