HPAVC/HPAVC CD-ROM.iso/pc/FAQSYS18.ZIP/FAQS.DAT/SBPRO.TXT

Text File | 1996-01-04 | 9.7 KB | 268 lines

                  ┌──────────────────────────────────┐
                  │ Programming the SoundBlaster Pro │
                  └──────────────────────────────────┘

                  Written for the PC-GPE by Mark Feldman
              e-mail address : [e-mail]
                               [e-mail]

             ┌───────────────────────────────────────────┐
             │      THIS FILE MAY NOT BE DISTRIBUTED     │
             │ SEPARATE TO THE ENTIRE PC-GPE COLLECTION. │
             └───────────────────────────────────────────┘


┌────────────┬───────────────────────────────────────────────────────────────
│ Disclaimer │
└────────────┘

I assume no responsibility whatsoever for any effect that this file, the
information contained therein or the use thereof has on you, your sanity,
computer, spouse, children, pets or anything else related to you or your
existance. No warranty is provided nor implied with this information.

┌──────────────┬─────────────────────────────────────────────────────────────
│ Introduction │
└──────────────┘

I still own a SoundBlaster 1.0 (don't laugh) so I haven't been able to
test any of the information in this file, ie don't take any of this as
fact.

┌──────────────┬─────────────────────────────────────────────────────────────
│ Stereo Sound │
└──────────────┘

Generating stereo FM sound on the SB Pro is similar to the way it's done
on the SB 1.x, you just use different ports for the left and right channels.
The file ADLIB.TXT has more information on this.

Generating stereo sounds with the DSP is similar to the mono method, but you
send *two* bytes for every sample. The first one goes to the left channel
and the second one goes to the right. You also need to reset the mixer chip
and tell the soundblaster you want to play a stereo sound (see below). This
has the advantage in that you can store the info for both channels in a
single data block and transfer it by still using only one DMA channel. The
WAV file format actually stores it's audio waveform data like this (see the
PC-GPE file WAV.TXT).


  Left channel bytes

  0       1       2       3       4       5       6
┌───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───
│   │   │   │   │   │   │   │   │   │   │   │   │   │   │   ........
└───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───
      0       1       2       3       4       5       6

  Right channel bytes

To play the sound the SoundBlaster Pro is set for stereo output and the DMA
chip is programmed to send this chunk as is.


┌────────────────────────┬───────────────────────────────────────────────────
│ The CT 1345 Mixer Chip │
└────────────────────────┘


You access the mixer registers the same way you access the regular SB
registers, but Port 2x4h is the index port and 2x5h is the data read/write
port, where x = 2 for base address jumper setting 220h
            x = 3 for base address jumper setting 230h
            x = 4 for base address jumper setting 240h

So setting a mixer register to a given value can be accomplished with the
following procedure:

{ base = 220h, 230 or 240h }
procedure SetMixerReg(base : word; index, value : byte);
begin
  Port[base + 4] := index;
  Port[base + 5] := value;
end;


You can also read a register's current value:

function GetMixerReg(base : word; index : byte) : byte;
begin
  Port[base + 4] := index;
  GetMixerReg := Port[base + 5];
end;





The Data Reset register is used to reset the mixer chip. Set this register to
0 before changing any of the other mixer registers.

              Index = 00h
              ┌───┬───┬───┬───┬───┬───┬───┬───┐
              │ 7 │ 6 │ 5 │ 4 │ 3 │ 2 │ 1 │ 0 │
              └───┴───┴───┴───┴───┴───┴───┴───┘
                └─────────────┬─────────────┘
                              │
                          Data Reset




The Input register selects the SB Pro sound input source and filter type.

              Index = 0Ch
              ┌───┬───┬───┬───┬───┬───┬───┬───┐
              │ 7 │ 6 │ 5 │ 4 │ 3 │ 2 │ 1 │ 0 │
              └───┴───┴───┴───┴───┴───┴───┴───┘
                        └───┬───┘   └─┬─┘
                            │         │
                ┌───────────┴─────┐ ┌─┴─────────────────┐
                │ In Filter       │ │ ADC Source        │
                │ 000 - Low       │ │ 00 - Microphone 1 │
                │ 001 - High      │ │ 01 - CD           │
                │ 010 - No Filter │ │ 10 - Microphone 2 │
                └─────────────────┘ │ 11 - Line In      │
                                    └───────────────────┘



The Output register determines whether to output sound in stereo or mono, in
stereo two bytes must be sent for each sample, the first one goes to the left
channel and the next one goes to the right. This register allows you to
bypass the output filter.

              Index = 0Eh
              ┌───┬───┬───┬───┬───┬───┬───┬───┐
              │ 7 │ 6 │ 5 │ 4 │ 3 │ 2 │ 1 │ 0 │
              └───┴───┴───┴───┴───┴───┴───┴───┘
                        │               │
           ┌────────────┴──────────┐ ┌──┴─────────┐
           │ DNFI                  │ │ VSTC       │
           │ 0 - Use O/P Filter    │ │ 0 - Mono   │
           │ 1 - Bypass O/P Filter │ │ 1 - Stereo │
           └───────────────────────┘ └────────────┘


The Master Volume register allows you to set the master volume of each
channel:

              Index = 22h
              ┌───┬───┬───┬───┬───┬───┬───┬───┐
              │ 7 │ 6 │ 5 │ 4 │ 3 │ 2 │ 1 │ 0 │
              └───┴───┴───┴───┴───┴───┴───┴───┘
                └─────┬─────┘   └─────┬─────┘
                      │               │
             ┌────────┴──────┐┌───────┴───────┐
             │ Master Volume ││ Master Volume │
             │     Left      ││     Right     │
             └───────────────┘└───────────────┘


The Voice Volume register allows you to set the volume of each channel for
DSP output:

              Index = 04h
              ┌───┬───┬───┬───┬───┬───┬───┬───┐
              │ 7 │ 6 │ 5 │ 4 │ 3 │ 2 │ 1 │ 0 │
              └───┴───┴───┴───┴───┴───┴───┴───┘
                └─────┬─────┘   └─────┬─────┘
                      │               │
              ┌───────┴──────┐┌───────┴──────┐
              │ Voice Volume ││ Voice Volume │
              │     Left     ││     Right    │
              └──────────────┘└──────────────┘

                 Voice Volume    Voice Volume
                    Left            Right


The FM Volume register allows you to set the volume of each channel for
FM wave synthesis:



              Index = 26h
              ┌───┬───┬───┬───┬───┬───┬───┬───┐
              │ 7 │ 6 │ 5 │ 4 │ 3 │ 2 │ 1 │ 0 │
              └───┴───┴───┴───┴───┴───┴───┴───┘
                └─────┬─────┘   └─────┬─────┘
                      │               │
                ┌─────┴─────┐   ┌─────┴─────┐
                │ FM Volume │   │ FM Volume │
                │   Left    │   │   Right   │
                └───────────┘   └───────────┘


The CD Volume register allows you to set the volume of each channel for
CD output:

              Index = 28h
              ┌───┬───┬───┬───┬───┬───┬───┬───┐
              │ 7 │ 6 │ 5 │ 4 │ 3 │ 2 │ 1 │ 0 │
              └───┴───┴───┴───┴───┴───┴───┴───┘
                └─────┬─────┘   └─────┬─────┘
                      │               │
                ┌─────┴─────┐   ┌─────┴─────┐
                │ CD Volume │   │ CD Volume │
                │   Left    │   │   Right   │
                └───────────┘   └───────────┘


The Line Volume register allows you to set the volume of each channel for
line in channel:


              Index = 2Eh
              ┌───┬───┬───┬───┬───┬───┬───┬───┐
              │ 7 │ 6 │ 5 │ 4 │ 3 │ 2 │ 1 │ 0 │
              └───┴───┴───┴───┴───┴───┴───┴───┘
                └─────┬─────┘   └─────┬─────┘
                      │               │
               ┌──────┴──────┐ ┌──────┴──────┐
               │ Line Volume │ │ Line Volume │
               │    Left     │ │    Right    │
               └─────────────┘ └─────────────┘

The Mic Mixing register allows you to set the input volume for the
microphone:

              Index = 0Ah
              ┌───┬───┬───┬───┬───┬───┬───┬───┐
              │ 7 │ 6 │ 5 │ 4 │ 3 │ 2 │ 1 │ 0 │
              └───┴───┴───┴───┴───┴───┴───┴───┘
                                    └───┬───┘
                                        │
                                 ┌──────┴─────┐
                                 │ Mic Mixing │
                                 └────────────┘

┌────────────┬───────────────────────────────────────────────────────────────
│ References │
└────────────┘

Title : The SoundBlaster Developpers Kit
Publishers : Creative Labs Inc
             Creative Technology PTE LTD

Title : Sound Blaster - The Official Book
Authors : Richard Heimlich, David M. Golden, Ivan Luk, Peter M. Ridge
Publishers : Osborne/McGraw Hill
ISBN : 0-07-881907-5

Some of the information in this file was either obtained from or verified
by the source code in a public domain library called SOUNDX by Peter
Sprenger. I haven't tried using his library yet (I don't have a C compiler
at the moment) but it looks very well done and contains numerous sound card
detection routines. Says Peter : "It would be nice, that when you make
something commercial with my routines, that you send me a copy of your
project or send me some bucks, just enough for pizza and coke to support my
night programming sessions. If you send me nothing, ok. But USE the stuff,
if you can need it!". Heh...a REAL programmer!

ftp site: ftp.uwp.edu
directory: /pub/msdos/demos/programming/game-dev/source
filename: soundx.zip