Optimized MAD16 PRO (OPTi 82c929) Sound controller initialization

Join me on a real oldschool / retro project:

Sound cards with a sound controller of type 82c929 (MAD16 PRO) were widely used in the mid 90s. These cards support the Windows Sound System mode, which with 48 kHz, 16 bit stereo sound exceeds the capabilities of a SB 16, as well as the Sound Blaster Pro standard, which was widespread in games at that time. Back in the day many manufacturers began to focus on driver support for Windows, and DOS drivers are often poorly programmed and just made to maintain compatibility. Also further developed codecs were used for these sound card, which are not fully supported by the previous drivers. This makes it difficult for today's friends of old hardware to get these sound cards to work properly. I therefore decided to program my own DOS driver, which lets the user change all possible settings and configure his sound card optimally.

Features:

• You can switch between Windows Sound System and Sound Blaster mode directly from the command line (or from a batch file).

• The driver offers many options to solve the most common problems with these sound cards:

  • The user can configure ALL possible settings of the sound controller in a convenient setup program. This makes a significantly improved Sound Blaster Pro compatibility possible and with my driver I have achieved sound in nearly all games that didn't work with the original drivers.
  • Some codecs do not fully calibrate at first start, resulting in distorted sound output. It is therefore often recommended to initialize the sound card twice. I have implemented an option for this: With the parameter /N the number of desired initializations can be specified.
  • While the OPTi 929 imitates the Sound Blaster Pro DSP very well, the imitation of the mixer chip was unfortunately not implemented as accurately. In some programs written for the SB Pro, the volume cannot be changed or there are problems with the output of audio in stereo. Often these problems can already be solved with the advanced settings of this driver, and my driver also offers a mixer program that bypasses the Sound Blaster mixer in the OPTi 929 and changes the volume directly in the codec, as well as a small TSR program that acts as a watchdog for the stereo output.

The driver consists of four main programs:

SETUP

Allows the comfortable configuration of the sound card. On the first screen you can set the default configuration for Sound Blaster, WSS, the MPU401 midi interface and a CD-ROM drive connected to the card. To be able to change all internal settings makes it easy to take settings that stop the sound card from working properly! So be careful when changing the advanced settings!

929INIT

This program initializes the sound card with the settings from the setup. The mode of the sound card can also be easily changed from the command line.

MIXER

Allows you to adjust the volume, configure the sound card's inputs for recording, and perform a sound check.

SBFIX

A small, memory-resident program that forces the sound card to output stereo sound in Sound Blaster Pro mode. If your game has issues with stereo output on OPTi929 soundcards try this small program to fix it. Just run it before starting the game.

The source code

The driver is written in Borland Pascal 7.0 and its inline assembler. Only SBFIX is written in pure assembly code (nasm).

You might wonder why I used an old-fashioned Pascal compiler? Quite simple: Back in the day I used to program under DOS mainly in Pascal and still have a lot of source code from that time. Fast text mode menu and screen handling, Sound Blaster and OPL2/3 FM stuff, MPU routines etc. All this I already had in my old Pascal source codes and therefore I could save myself a lot of work doing this retro-project in good ol' Pascal.

Low level code to interact with the hardware:

OPTI929.PAS

This file contains all functions to initialize and (re)configure the OPTi 82C929 sound controller.

AD1848.PAS

In this file you will find all code needed to interact with an Analog Devices AD1848 compatible codec.
Therefore this unit can also be used for playing audio via the Windows Sound System (see the use in MIXER.PAS for an example how to do this).

OPLFM.PAS

Code to interact with Yamaha YM3812/ YMF262 (OPL2/OPL3) FM synthesis chips.

OPL4.PAS

Code to interact with Yamaha YMF278 OPL4 FM and Wavetable chip.

MPU.PAS

Code to interact with MPU 401 Midi interface

SBPRO.PAS

All necessary code to interact with an Sound BLaster Pro compatible card and it's mixer.

SBFIX.ASM

The assembly source code for the little TSR to fix some issues with stereo playback. Use NASM to compile it.

All the datasheets for the OPTi 82c929 and the codecs it supports can be found in the DOCS folder.

Additional units and the main programs

BMF.PAS

Player for FM tunes in the "Easy adlib" file format (*.bmf).

TEXTMODE.PAS

Fast drawing routines for the 80x25 Textmode. Replacement of Borlands CRT unit.

MISC.PAS

Some routines for bit manipulation, timing, displaying hex numbers and more...

SETUP.PAS, MIXER.PAS and 929INIT.PAS

The three main files of my driver/initialisation program.

Some Screenshots

The Setup

The Mixer

The main program for initialization

Thanks and greetings go to the community of https://dosreloaded.de With their feedback and suggestions for improvement, they have always made me continue and improve this project. Without the support from the forum, this would probably have been just a simple attempt to initialize a soundcard with my own program.