yyzkevin wrote on 2021-04-06, 19:23:
I made a breakout/dev board for the PCMCIA port, it has a flash chip and GAL to handle some of the basic logic needed and then has some ports for my logic analyzer, and a header that I can use to connect to the breadboard for testing different functions. I have a couple other pcmcia projects I am working on, this sound card portion has me off on a tangent and I am very interested in the challenge of implementing this DMA patent. Actually it started off hey let me just stick an OPL3 on a pcmcia card, then it was well why not throw an MPU-401 in there too, oh how about an onboard wavetable oh and soundblaster compatibility.
the FPGA idea is interesting, but I think it is well outside the scope of what I am trying to do right now. I looked at FPGA's early on but working in a purely 5V system creates some hassles too. something to look at one day. If you could find a place I could actually buy that fpga board it would be interesting to develop with but I do not believe it is available, I came across it last year. I also have a PCMCIA FPGA board I purchased on ebay but without documentation I could not get far.
Regarding the whole "Actually it started off hey let me just stick an OPL3 on a pcmcia card, then it was well why not throw an MPU-401 in there too, oh how about an onboard wavetable oh and soundblaster compatibility" you mentioned,
I can understand it's getting a bit complex for you and it might put you under some pressure to get this working, also due to the fact that you're doing it all by yourself,
eg, nobody has come forward to work with you on the project (aside from some helpful posts made by various forum member here of course) so, why don't we, at this point, in order to alleviate the pressure and "unknowns",
why don't we just decide right now on a feature-freeze, how we're going to implement it physically, and we stop adding new ideas or features that keep making thing more complex and stressful for you.
I wish I had the knowledge you have, if I did, I would be working together with you on this, but alas, I'm a mere software developer, and I've no experience with hardware at this level...
I'm also a bit confused at this point if you're still wanting to implement things as originally planned, eg the LXSidecar concept with the PCMCIA card being just the IO connections,
and having most of the actual hardware inside the sidecar box that's connected to the card and makes the 200lx 10-15 centimetres "wider",
or, if you're just engineering a PCMCIA soundcard instead. (just a PCMCIA card), so as to have an affordable alternative to the Roland SCP-55 PCMCIA card which is super rare and expensive to get hold off.
Could you explain what you're current intentions are here ???
It's important that we're all on the same line and that we know exactly what each other's intentions/views are, otherwise problems could arise in the future...
So, assuming we're still doing the LXSideCar idea, Why don't we decide and finalize a complete specification-freeze right now for the LXSideCar v1.0,
and you work towards completing it, while, once you've got the final PCB design, I can step in and help you with the design of the case and the analogue output part: amplifier board, integrated speaker(s) and line out / speaker 3.5" jacks.
Once we've decided on the specifications for the LXsidecar v1.0, they will be final and we won't change anything or add anything else, unless, it's due to a technical issue (eg, you are unable to get the a certain feature working due to some brick wall technical constraint...)
Any other features or ideas to add would have to go onto another specifications list for the v2.0 LXsidecar, and we won't look at those until the v1.0 is done...
So, from my point view, the current feature freeze would be the following specifications:
* PCMCIA Type II card, which is connected (it's all one aluminium part) to the LXSideCar box that attached itself to the left side of the 200LX through the PCMCIA card going into the 200LX's PCMCIA slot.
Similar to the original 3D renderings I made at the beginning when we created the project a few months ago.
I will try to design the enclosure so that it can be inserted and used in other systems like old laptops or other PC compatible MS-DOS Palmtops or mini-laptops of the late '80s and early '90s...
The card and all its hardware/features should work on a 8086 system, so we can't use TSRs etc for 386 CPUs, like some of serdaco's parallel port based products do (their dream.fr chip based S2P and OPL2/3LPT for example)
Specifications / Features:
1. One PCMCIA slot, that always works, and is converted into a physical CF card socket instead, so you can only insert CF cards into it, to save space and make the enclosure smaller.
This slot is basically meant to be your system's "hard drive" slot so you can put your 1GB or 2GB CF card in it and have all your software and files at your disposal,
when using either the 2nd PCMCIA slot (see next item on the list) which accepts proper PCMCIA cards, and works when the sound hardware is disabled, or, load and play games/apps from your large CF card, while using the audio hardware in the LXSideCar.
2. One additional/2nd PCMCIA Type II slot, that only works when the sound hardware in the LXSideCar is disabled, as explained above, this is a full Physical Type II PCMCIA Slot.
3a: One or 2 small speakers (the kind I purchased a few of, the 1-watt modern mobile phone/tablet speakers. (bought these for about $3 per speaker on element14)
3b: A mono or stereo (depending on if we put one or two speakers in the LXSidecar case) tiny PCB mono or stereo 1 watt per channel amplifier board (found some for $2.95 each on aliexpress)
3c: 2x 3.5" jacks, one on the front of the LXSideCar enclosure, for headphones, and one on the back which is a line-out for connecting to an amp or a set of amplified speakers. To save space/complexity/cost, we could drop the line-out jack and just have people use the headphone jack on low volume instead...
4a: A Hardware MPU401
4b: A dream.fr general midi synthesizer, that's connected to the hardware MPU-401 (or, if you can find a better solution, maybe another chip that has the same function)
5: A Soundblaster compatible implementation: an 8bit or 16bit DAC for digital audio output, and an OPL2, 2x OPL2s or an OPL3 for the music part of the Soundblaster. (maybe you can get the Soundblaster DSP + OPL3 working together with the MPU + dream.fr,
so that people can select the MPU401+dream.fr for game music, and the Soundblaster for game sound effects through its DAC.
Several games supported this kind of setup, and there are a decent amount of those that run on the 200LX and similar machines.
I don't know what kind of Soundblaster you would want to try and implement, either one of the first ones like the Soundblaster 1.0 (mono 8-bit 22KHz out) and an OPL2 chip (which is also mono),
or, a SoundBlaster 2.0 which had a mono 8-bit 44.1KHz sound output instead.
Just for your information: Here is an overview of the different Creative SoundBlaster cards that were released, prior to the later AWE32/64 ranges:
Soundblaster 1.0/1.5 DAC: mono, 8bit, up to 22KHz output | FM MUSIC: one mono OPL2 chip.
Soundblaster 2.0 DAC: mono, 8bit, up to 44.1KHz output | FM MUSIC: one mono OPL2 chip.
Soundblaster Pro DAC: 8bit, up to 22.05 kHz stereo or 44.1 kHz mono | FM MUSIC: two OPL2 chips for stereo sound.
Soundblaster Pro 2.0 DAC: 8bit, up to 22.05 kHz stereo or 44.1 kHz mono | FM MUSIC: one OPL3 stereo chip.
Soundblaster 16 DAC: 16bit, up to 44.1 kHz stereo | FM MUSIC: one OPL3 stereo chip.
Also had a connector to install a wavetable synth daughterboard.
Note that all these cards are also Adlib compatible (for games that only supported adlib)
Of course, trying to implement the latest of these cards that's possible would be best, and personally, if it's at all possible to have a Soundblaster 16 compatible like feature, where we can play good old CD-quality 44.1Khz 16-bit stereo, that would be a dream come true for me 😀
Personally, if you could manage to get a DAC that supports 44.1KHz and 16-bit sample quality, adding a $5 MP3 codec IC to the board would be awesome, as it would turn the 200LX into a useable MP3 player,
and, since the codec is doing all the work, the CPU won't have much to do while playing music, so it could run as a TSR 😉 But, I'm definitely not going to add that to the list above at this time,
as I don't want to stress you out 😉 So let's leave that for the v2.0 specifications list in the future 😉 (Unless you feel you can add it, it's up to you to decide, you have the final say on the specs list!).
Anyway, you're the person who's doing 99% of the work right now and is designing the hardware, so it's up to you to decide what to implement, my list above is just how I see the project currently and what I would love to see as the v1.0 of the LXSideCar.
So, if you look at the list of features, we kinda discussed here and there in our posts and mails on implementing already everything but the Soundblaster feature,
which is something that you've initiated during the process fairly recently...
What are your thoughts on this yyzkevin ?
* Are you still doing the LXSideCar project or are you currently refocusing on trying to produce just a PCMCIA sound card instead?
* Should we do a feature freeze and make a final list of specs for the v1.0 LXSideCar at this time?
* What would you want to have the list of features look like? Maybe make a list of your own so I can see it and I can modify the finalized feature list of the v1.0 LXSideCar.
Do you agree with my specifications list for the v1.0,
or do you want to add or remove any features ? (For example, you spoke about maybe adding your serial WIFI feature)
* Are you going to continue with trying the Soundblaster implementation? (cause I think you've hit some problems, according to some posts you made a week or so ago where you were asking for some help)
PS: I'm happy to hear from the others here in this thread, please post your points of view/features you would find essential or unnecessary...