Jo22 wrote:And what about the PAS/PAS16 ? It was the second largest standard beside GUS and their DACs were accessible
via a high-level API […]
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And what about the PAS/PAS16 ? It was the second largest standard beside GUS and their DACs were accessible
via a high-level API through mvsound.sys. Wouldn't it be possible for it (the PAS DAC) to be usable without using ISA DMA ?
Maybe some sort of PAS->Covox wrapper that works similar to Virtual Sound Blaster, but without the quirks and limits of the SB architecture ?
An mvsound.sys-emulator, so to say. These are just my thoughts, so please don't be up set.. Ans it's no feature request, of course. 😅
I found your idea so intriguing that I went and did some digging! 😀
I found a download link for the PAS SDK at the bottom of this (quite long and extensive) post by P4R4D0X (all the way at the bottom of that post, a Mediafire link to a file called PROAUDIO.ZIP). I browsed through some of the assembly and C sources, but there were still a lot of references to direct DMA programming in there. 🙁
Also, if I understood the documentation correctly, the MVSOUND.SYS file only provides abstraction for detection, hardware initialization and mixer control. Either it doesn't offer a completely abstracted programming API, or it is bypassed by many games in lieu of direct programming. Various sources on-line appear to be providing conflicting information about this, compared to the documentation that came with the SDK:
https://nerdlypleasures.blogspot.com/2017/01/ … -crown-pro.html
https://en.wikipedia.org/wiki/Media_Vision_Pro_AudioSpectrum
It would be nice if someone here in the know could provide some clarification on this. Does MVSOUND.SYS abstract away the DMA programming part of Pro Audio Spectrum cards? And if so, how many games accessed the cards through this abstraction instead of directly?
LABS wrote:LPT is ok for sending FM commands, but it is too slow for PCM playback. Standart Parallel Port's bitrate is 150kbit/s, which is 18.75kbyte/s. Even 8-bit PCM transfer at 22050Hz in DMA mode requires at least a theoretical minimum of 22.05 kbyte/s, but DMA is not available for SPP transfers. EEP and ECP support up to 2.5 mbit/s and ECP even supports DMA, but.. there is no reason to implement SB's DAC on LPT. It requires 4 more I/O ports to be implemented somehow, precompiled soft will never work with it directly, but writing a TSR driver is unrelyable (SB PCI drivers for DOS was a good example), so it is not worth the effort. FM on LPT is cool for some software playing tunes on original chip, but SB-compatible DAC on LPT is just useless.
I wouldn't call it useless. From what I gather in many topics here, Sound Blaster emulation over a parallel port, or at least support for digital audio over a parallel port, to go along with recent retro music hardware projects such as dreamblaster's OPL2LPT, OPL3LPT, TNDLPT and MIDILPT projects, is pretty much considered a holy grail in order to get games with sound working on older laptops, Microchannel-based PS/2 systems and modern post-ISA PCs.
Most games only output sound at 11025kHz, which would require only half the bandwidth you describe, which would be feasible over an LPT port, possibly even on a 386 machine, even when combined with something like OPL2/OPL3 on the same port, perhaps through some kind of latching mechanism in the parallel port device to allow for multiplexing and thus simultaneous music and digital audio output.
Also, how would you explain the existence of products such as these? https://youtu.be/t7VxWbCgWHk