Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | |
| 2 | Sound Blaster Live mixer / default DSP code |
| 3 | =========================================== |
| 4 | |
| 5 | |
| 6 | The EMU10K1 chips have a DSP part which can be programmed to support |
| 7 | various ways of sample processing, which is described here. |
Matt LaPlante | 4ae0edc | 2006-11-30 04:58:40 +0100 | [diff] [blame^] | 8 | (This article does not deal with the overall functionality of the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | EMU10K1 chips. See the manuals section for further details.) |
| 10 | |
| 11 | The ALSA driver programs this portion of chip by default code |
| 12 | (can be altered later) which offers the following functionality: |
| 13 | |
| 14 | |
| 15 | 1) IEC958 (S/PDIF) raw PCM |
| 16 | -------------------------- |
| 17 | |
| 18 | This PCM device (it's the 4th PCM device (index 3!) and first subdevice |
| 19 | (index 0) for a given card) allows to forward 48kHz, stereo, 16-bit |
| 20 | little endian streams without any modifications to the digital output |
| 21 | (coaxial or optical). The universal interface allows the creation of up |
| 22 | to 8 raw PCM devices operating at 48kHz, 16-bit little endian. It would |
| 23 | be easy to add support for multichannel devices to the current code, |
| 24 | but the conversion routines exist only for stereo (2-channel streams) |
| 25 | at the time. |
| 26 | |
| 27 | Look to tram_poke routines in lowlevel/emu10k1/emufx.c for more details. |
| 28 | |
| 29 | |
| 30 | 2) Digital mixer controls |
| 31 | ------------------------- |
| 32 | |
| 33 | These controls are built using the DSP instructions. They offer extended |
| 34 | functionality. Only the default build-in code in the ALSA driver is described |
| 35 | here. Note that the controls work as attenuators: the maximum value is the |
| 36 | neutral position leaving the signal unchanged. Note that if the same destination |
| 37 | is mentioned in multiple controls, the signal is accumulated and can be wrapped |
| 38 | (set to maximal or minimal value without checking of overflow). |
| 39 | |
| 40 | |
| 41 | Explanation of used abbreviations: |
| 42 | |
| 43 | DAC - digital to analog converter |
| 44 | ADC - analog to digital converter |
| 45 | I2S - one-way three wire serial bus for digital sound by Philips Semiconductors |
| 46 | (this standard is used for connecting standalone DAC and ADC converters) |
| 47 | LFE - low frequency effects (subwoofer signal) |
| 48 | AC97 - a chip containing an analog mixer, DAC and ADC converters |
| 49 | IEC958 - S/PDIF |
| 50 | FX-bus - the EMU10K1 chip has an effect bus containing 16 accumulators. |
| 51 | Each of the synthesizer voices can feed its output to these accumulators |
| 52 | and the DSP microcontroller can operate with the resulting sum. |
| 53 | |
| 54 | |
| 55 | name='Wave Playback Volume',index=0 |
| 56 | |
| 57 | This control is used to attenuate samples for left and right PCM FX-bus |
| 58 | accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples. |
| 59 | The result samples are forwarded to the front DAC PCM slots of the AC97 codec. |
| 60 | |
| 61 | name='Wave Surround Playback Volume',index=0 |
| 62 | |
| 63 | This control is used to attenuate samples for left and right PCM FX-bus |
| 64 | accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples. |
| 65 | The result samples are forwarded to the rear I2S DACs. These DACs operates |
| 66 | separately (they are not inside the AC97 codec). |
| 67 | |
| 68 | name='Wave Center Playback Volume',index=0 |
| 69 | |
| 70 | This control is used to attenuate samples for left and right PCM FX-bus |
| 71 | accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples. |
| 72 | The result is mixed to mono signal (single channel) and forwarded to |
| 73 | the ??rear?? right DAC PCM slot of the AC97 codec. |
| 74 | |
| 75 | name='Wave LFE Playback Volume',index=0 |
| 76 | |
| 77 | This control is used to attenuate samples for left and right PCM FX-bus |
| 78 | accumulators. ALSA uses accumulators 0 and 1 for left and right PCM. |
| 79 | The result is mixed to mono signal (single channel) and forwarded to |
| 80 | the ??rear?? left DAC PCM slot of the AC97 codec. |
| 81 | |
| 82 | name='Wave Capture Volume',index=0 |
| 83 | name='Wave Capture Switch',index=0 |
| 84 | |
| 85 | These controls are used to attenuate samples for left and right PCM FX-bus |
| 86 | accumulator. ALSA uses accumulators 0 and 1 for left and right PCM. |
| 87 | The result is forwarded to the ADC capture FIFO (thus to the standard capture |
| 88 | PCM device). |
| 89 | |
| 90 | name='Music Playback Volume',index=0 |
| 91 | |
| 92 | This control is used to attenuate samples for left and right MIDI FX-bus |
| 93 | accumulators. ALSA uses accumulators 4 and 5 for left and right MIDI samples. |
| 94 | The result samples are forwarded to the front DAC PCM slots of the AC97 codec. |
| 95 | |
| 96 | name='Music Capture Volume',index=0 |
| 97 | name='Music Capture Switch',index=0 |
| 98 | |
| 99 | These controls are used to attenuate samples for left and right MIDI FX-bus |
| 100 | accumulator. ALSA uses accumulators 4 and 5 for left and right PCM. |
| 101 | The result is forwarded to the ADC capture FIFO (thus to the standard capture |
| 102 | PCM device). |
| 103 | |
| 104 | name='Surround Playback Volume',index=0 |
| 105 | |
| 106 | This control is used to attenuate samples for left and right rear PCM FX-bus |
| 107 | accumulators. ALSA uses accumulators 2 and 3 for left and right rear PCM samples. |
| 108 | The result samples are forwarded to the rear I2S DACs. These DACs operate |
| 109 | separately (they are not inside the AC97 codec). |
| 110 | |
| 111 | name='Surround Capture Volume',index=0 |
| 112 | name='Surround Capture Switch',index=0 |
| 113 | |
| 114 | These controls are used to attenuate samples for left and right rear PCM FX-bus |
| 115 | accumulators. ALSA uses accumulators 2 and 3 for left and right rear PCM samples. |
| 116 | The result is forwarded to the ADC capture FIFO (thus to the standard capture |
| 117 | PCM device). |
| 118 | |
| 119 | name='Center Playback Volume',index=0 |
| 120 | |
| 121 | This control is used to attenuate sample for center PCM FX-bus accumulator. |
| 122 | ALSA uses accumulator 6 for center PCM sample. The result sample is forwarded |
| 123 | to the ??rear?? right DAC PCM slot of the AC97 codec. |
| 124 | |
| 125 | name='LFE Playback Volume',index=0 |
| 126 | |
| 127 | This control is used to attenuate sample for center PCM FX-bus accumulator. |
| 128 | ALSA uses accumulator 6 for center PCM sample. The result sample is forwarded |
| 129 | to the ??rear?? left DAC PCM slot of the AC97 codec. |
| 130 | |
| 131 | name='AC97 Playback Volume',index=0 |
| 132 | |
| 133 | This control is used to attenuate samples for left and right front ADC PCM slots |
| 134 | of the AC97 codec. The result samples are forwarded to the front DAC PCM |
| 135 | slots of the AC97 codec. |
| 136 | ******************************************************************************** |
| 137 | *** Note: This control should be zero for the standard operations, otherwise *** |
| 138 | *** a digital loopback is activated. *** |
| 139 | ******************************************************************************** |
| 140 | |
| 141 | name='AC97 Capture Volume',index=0 |
| 142 | |
| 143 | This control is used to attenuate samples for left and right front ADC PCM slots |
| 144 | of the AC97 codec. The result is forwarded to the ADC capture FIFO (thus to |
| 145 | the standard capture PCM device). |
| 146 | ******************************************************************************** |
| 147 | *** Note: This control should be 100 (maximal value), otherwise no analog *** |
| 148 | *** inputs of the AC97 codec can be captured (recorded). *** |
| 149 | ******************************************************************************** |
| 150 | |
| 151 | name='IEC958 TTL Playback Volume',index=0 |
| 152 | |
| 153 | This control is used to attenuate samples from left and right IEC958 TTL |
| 154 | digital inputs (usually used by a CDROM drive). The result samples are |
| 155 | forwarded to the front DAC PCM slots of the AC97 codec. |
| 156 | |
| 157 | name='IEC958 TTL Capture Volume',index=0 |
| 158 | |
| 159 | This control is used to attenuate samples from left and right IEC958 TTL |
| 160 | digital inputs (usually used by a CDROM drive). The result samples are |
| 161 | forwarded to the ADC capture FIFO (thus to the standard capture PCM device). |
| 162 | |
| 163 | name='Zoom Video Playback Volume',index=0 |
| 164 | |
| 165 | This control is used to attenuate samples from left and right zoom video |
| 166 | digital inputs (usually used by a CDROM drive). The result samples are |
| 167 | forwarded to the front DAC PCM slots of the AC97 codec. |
| 168 | |
| 169 | name='Zoom Video Capture Volume',index=0 |
| 170 | |
| 171 | This control is used to attenuate samples from left and right zoom video |
| 172 | digital inputs (usually used by a CDROM drive). The result samples are |
| 173 | forwarded to the ADC capture FIFO (thus to the standard capture PCM device). |
| 174 | |
| 175 | name='IEC958 LiveDrive Playback Volume',index=0 |
| 176 | |
| 177 | This control is used to attenuate samples from left and right IEC958 optical |
| 178 | digital input. The result samples are forwarded to the front DAC PCM slots |
| 179 | of the AC97 codec. |
| 180 | |
| 181 | name='IEC958 LiveDrive Capture Volume',index=0 |
| 182 | |
| 183 | This control is used to attenuate samples from left and right IEC958 optical |
| 184 | digital inputs. The result samples are forwarded to the ADC capture FIFO |
| 185 | (thus to the standard capture PCM device). |
| 186 | |
| 187 | name='IEC958 Coaxial Playback Volume',index=0 |
| 188 | |
| 189 | This control is used to attenuate samples from left and right IEC958 coaxial |
| 190 | digital inputs. The result samples are forwarded to the front DAC PCM slots |
| 191 | of the AC97 codec. |
| 192 | |
| 193 | name='IEC958 Coaxial Capture Volume',index=0 |
| 194 | |
| 195 | This control is used to attenuate samples from left and right IEC958 coaxial |
| 196 | digital inputs. The result samples are forwarded to the ADC capture FIFO |
| 197 | (thus to the standard capture PCM device). |
| 198 | |
| 199 | name='Line LiveDrive Playback Volume',index=0 |
| 200 | name='Line LiveDrive Playback Volume',index=1 |
| 201 | |
| 202 | This control is used to attenuate samples from left and right I2S ADC |
| 203 | inputs (on the LiveDrive). The result samples are forwarded to the front |
| 204 | DAC PCM slots of the AC97 codec. |
| 205 | |
| 206 | name='Line LiveDrive Capture Volume',index=1 |
| 207 | name='Line LiveDrive Capture Volume',index=1 |
| 208 | |
| 209 | This control is used to attenuate samples from left and right I2S ADC |
| 210 | inputs (on the LiveDrive). The result samples are forwarded to the ADC |
| 211 | capture FIFO (thus to the standard capture PCM device). |
| 212 | |
| 213 | name='Tone Control - Switch',index=0 |
| 214 | |
| 215 | This control turns the tone control on or off. The samples for front, rear |
| 216 | and center / LFE outputs are affected. |
| 217 | |
| 218 | name='Tone Control - Bass',index=0 |
| 219 | |
| 220 | This control sets the bass intensity. There is no neutral value!! |
| 221 | When the tone control code is activated, the samples are always modified. |
| 222 | The closest value to pure signal is 20. |
| 223 | |
| 224 | name='Tone Control - Treble',index=0 |
| 225 | |
| 226 | This control sets the treble intensity. There is no neutral value!! |
| 227 | When the tone control code is activated, the samples are always modified. |
| 228 | The closest value to pure signal is 20. |
| 229 | |
| 230 | name='IEC958 Optical Raw Playback Switch',index=0 |
| 231 | |
| 232 | If this switch is on, then the samples for the IEC958 (S/PDIF) digital |
| 233 | output are taken only from the raw FX8010 PCM, otherwise standard front |
| 234 | PCM samples are taken. |
| 235 | |
| 236 | name='Headphone Playback Volume',index=1 |
| 237 | |
| 238 | This control attenuates the samples for the headphone output. |
| 239 | |
| 240 | name='Headphone Center Playback Switch',index=1 |
| 241 | |
| 242 | If this switch is on, then the sample for the center PCM is put to the |
| 243 | left headphone output (useful for SB Live cards without separate center/LFE |
| 244 | output). |
| 245 | |
| 246 | name='Headphone LFE Playback Switch',index=1 |
| 247 | |
| 248 | If this switch is on, then the sample for the center PCM is put to the |
| 249 | right headphone output (useful for SB Live cards without separate center/LFE |
| 250 | output). |
| 251 | |
| 252 | |
| 253 | 3) PCM stream related controls |
| 254 | ------------------------------ |
| 255 | |
| 256 | name='EMU10K1 PCM Volume',index 0-31 |
| 257 | |
| 258 | Channel volume attenuation in range 0-0xffff. The maximum value (no |
| 259 | attenuation) is default. The channel mapping for three values is |
| 260 | as follows: |
| 261 | |
| 262 | 0 - mono, default 0xffff (no attenuation) |
| 263 | 1 - left, default 0xffff (no attenuation) |
| 264 | 2 - right, default 0xffff (no attenuation) |
| 265 | |
| 266 | name='EMU10K1 PCM Send Routing',index 0-31 |
| 267 | |
| 268 | This control specifies the destination - FX-bus accumulators. There are |
| 269 | twelve values with this mapping: |
| 270 | |
| 271 | 0 - mono, A destination (FX-bus 0-15), default 0 |
| 272 | 1 - mono, B destination (FX-bus 0-15), default 1 |
| 273 | 2 - mono, C destination (FX-bus 0-15), default 2 |
| 274 | 3 - mono, D destination (FX-bus 0-15), default 3 |
| 275 | 4 - left, A destination (FX-bus 0-15), default 0 |
| 276 | 5 - left, B destination (FX-bus 0-15), default 1 |
| 277 | 6 - left, C destination (FX-bus 0-15), default 2 |
| 278 | 7 - left, D destination (FX-bus 0-15), default 3 |
| 279 | 8 - right, A destination (FX-bus 0-15), default 0 |
| 280 | 9 - right, B destination (FX-bus 0-15), default 1 |
| 281 | 10 - right, C destination (FX-bus 0-15), default 2 |
| 282 | 11 - right, D destination (FX-bus 0-15), default 3 |
| 283 | |
| 284 | Don't forget that it's illegal to assign a channel to the same FX-bus accumulator |
| 285 | more than once (it means 0=0 && 1=0 is an invalid combination). |
| 286 | |
| 287 | name='EMU10K1 PCM Send Volume',index 0-31 |
| 288 | |
| 289 | It specifies the attenuation (amount) for given destination in range 0-255. |
| 290 | The channel mapping is following: |
| 291 | |
| 292 | 0 - mono, A destination attn, default 255 (no attenuation) |
| 293 | 1 - mono, B destination attn, default 255 (no attenuation) |
| 294 | 2 - mono, C destination attn, default 0 (mute) |
| 295 | 3 - mono, D destination attn, default 0 (mute) |
| 296 | 4 - left, A destination attn, default 255 (no attenuation) |
| 297 | 5 - left, B destination attn, default 0 (mute) |
| 298 | 6 - left, C destination attn, default 0 (mute) |
| 299 | 7 - left, D destination attn, default 0 (mute) |
| 300 | 8 - right, A destination attn, default 0 (mute) |
| 301 | 9 - right, B destination attn, default 255 (no attenuation) |
| 302 | 10 - right, C destination attn, default 0 (mute) |
| 303 | 11 - right, D destination attn, default 0 (mute) |
| 304 | |
| 305 | |
| 306 | |
| 307 | 4) MANUALS/PATENTS: |
| 308 | ------------------- |
| 309 | |
| 310 | ftp://opensource.creative.com/pub/doc |
| 311 | ------------------------------------- |
| 312 | |
| 313 | Files: |
| 314 | LM4545.pdf AC97 Codec |
| 315 | |
| 316 | m2049.pdf The EMU10K1 Digital Audio Processor |
| 317 | |
| 318 | hog63.ps FX8010 - A DSP Chip Architecture for Audio Effects |
| 319 | |
| 320 | |
| 321 | WIPO Patents |
| 322 | ------------ |
| 323 | Patent numbers: |
| 324 | WO 9901813 (A1) Audio Effects Processor with multiple asynchronous (Jan. 14, 1999) |
| 325 | streams |
| 326 | |
| 327 | WO 9901814 (A1) Processor with Instruction Set for Audio Effects (Jan. 14, 1999) |
| 328 | |
| 329 | WO 9901953 (A1) Audio Effects Processor having Decoupled Instruction |
| 330 | Execution and Audio Data Sequencing (Jan. 14, 1999) |
| 331 | |
| 332 | |
| 333 | US Patents (http://www.uspto.gov/) |
| 334 | ---------------------------------- |
| 335 | |
| 336 | US 5925841 Digital Sampling Instrument employing cache memory (Jul. 20, 1999) |
| 337 | |
| 338 | US 5928342 Audio Effects Processor integrated on a single chip (Jul. 27, 1999) |
| 339 | with a multiport memory onto which multiple asynchronous |
| 340 | digital sound samples can be concurrently loaded |
| 341 | |
| 342 | US 5930158 Processor with Instruction Set for Audio Effects (Jul. 27, 1999) |
| 343 | |
| 344 | US 6032235 Memory initialization circuit (Tram) (Feb. 29, 2000) |
| 345 | |
| 346 | US 6138207 Interpolation looping of audio samples in cache connected to (Oct. 24, 2000) |
| 347 | system bus with prioritization and modification of bus transfers |
| 348 | in accordance with loop ends and minimum block sizes |
| 349 | |
| 350 | US 6151670 Method for conserving memory storage using a (Nov. 21, 2000) |
| 351 | pool of short term memory registers |
| 352 | |
| 353 | US 6195715 Interrupt control for multiple programs communicating with (Feb. 27, 2001) |
| 354 | a common interrupt by associating programs to GP registers, |
| 355 | defining interrupt register, polling GP registers, and invoking |
| 356 | callback routine associated with defined interrupt register |