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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. 8 (This article does not deal with the overall functionality of the 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='Synth 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='Synth Capture Volume',index=0 97 name='Synth 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