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barnieg

[AQUARIUS] AY-8914? programming

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As for an SD drive or something like that, Jay and I think even Martin are working on a solution to get some kind of speedy mass storage available for the Aquarius. This would make the Aquarius a more serious homebrew system.

:cool: Thats good to know. Drop me a PM if you need any help or want to bounce ideas of somebody.

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The problem with internal mods is not everybody has them installed. So if you write software for them, the percentage take-up of your game is a niche of a niche. If it plugs in the cart slot then its worth doing a game that targets the advanced hardware. I think the Aquarius needs an SD drive of some kind. That would make it much more fun to use as a system and to develop new homebrews for.

I agree. It seems that hobbyists today are much less likely to want to take a soldering iron to their systems than they were back in the 80s, which in a way is odd considering that the Web provides access to more resources and much cheaper hardware (used systems from eBay, etc) than were available back then. I think modern computers have "spoiled" users to the point where they want Plug-and-Play solutions which don't involve getting anywhere near the underlying hardware. Unfortunately, even something like SuperFont is a drastic enough change to the Aquarius that it requires an internal mod. Practically speaking, any Aquarius game that supports internal upgrades would have to do so only optionally; if a game doesn't run on a stock Aquarius, it will be unplayable for a large percentage of Aquarius owners.

 

I've decided to put my own SuperFont plans on hold until we see the fruits of Bruce's efforts (since there's no point in making two "competing" implementations of the same upgrade), so I'm focusing right now on PC connectivity via USB (I'm working on that now) and finally getting my first game together. Mass storage on the Aquarius will come after that if somebody else doesn't beat me to it, and since everybody seems to want to use SD cards, that's probably what I'll end up using, if I can find a reasonably "future-proof" way of doing so. The SD standards seem to change a lot, and the last thing I want is for my users to have to hunt down tiny old weird memory cards (as owners of the Cuttle Cart 2 and Cuttle Cart 3 have had to do) to work with my hardware a few years down the road.

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Mass storage on the Aquarius will come after that if somebody else doesn't beat me to it, and since everybody seems to want to use SD cards, that's probably what I'll end up using, if I can find a reasonably "future-proof" way of doing so. The SD standards seem to change a lot, and the last thing I want is for my users to have to hunt down tiny old weird memory cards (as owners of the Cuttle Cart 2 and Cuttle Cart 3 have had to do) to work with my hardware a few years down the road.

Its only the form factor e.g. card socket that mostly changes. They haven't changed the "logon" procedure to get the cards into a good state for a long time but extra commands do get added. There are ways of detecting between MMC, SD and SDHC by responses in the initialisation sequence.

 

After Hive has shipped I could easily do a 5v AVR part that was basically a self contained interface to an SD/microSD card if you want. You'd just need a couple of memory mapped I/O ports to get a list of files/folders and to instruct the AVR to navigate and load files. That would probably save you quite a bit of time and simplify your game selection menu quite a bit.

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Its only the form factor e.g. card socket that mostly changes. They haven't changed the "logon" procedure to get the cards into a good state for a long time but extra commands do get added. There are ways of detecting between MMC, SD and SDHC by responses in the initialisation sequence.

 

After Hive has shipped I could easily do a 5v AVR part that was basically a self contained interface to an SD/microSD card if you want. You'd just need a couple of memory mapped I/O ports to get a list of files/folders and to instruct the AVR to navigate and load files. That would probably save you quite a bit of time and simplify your game selection menu quite a bit.

Hey, great! I haven't worked much with memory cards before, which is one reason I want to do it for the Aquarius, and that would be extremely helpful. What I have in mind for the Aquarius is general-purpose storage which would amount to a hard drive equivalent. I'd love to give the users the ability to load/save BASIC programs and data files directly to a FAT32 filesystem, for example. Loading cartridge images from the SD card would require a bankswitched RAM cartridge to hold the images, but I'm working on one of those now for use with my USB development cable.

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Hey, great! I haven't worked much with memory cards before, which is one reason I want to do it for the Aquarius, and that would be extremely helpful. What I have in mind for the Aquarius is general-purpose storage which would amount to a hard drive equivalent. I'd love to give the users the ability to load/save BASIC programs and data files directly to a FAT32 filesystem. Loading cartridge images from the SD card would require a bankswitched RAM cartridge to hold the images, but I'm working on one of those now for use with my USB development cable.

Can you easily extend the built in ROM commands? Although its not enabled in Hive, my FAT code also supports folder creation with file write/seek/append. You'd probably also want some kind of RTC on such a device so that the file stamps could be up to date. If you put a low end NXP LPC ARM chip (like in Harmony/Melody) on the PCB it could be the ROM/RAM as well as access the SD/microSD card. However, not many of those parts come in .1" pitch DIP (if any) so it all depends on if you want to go to a full/part surface mount solution.

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Can you easily extend the built in ROM commands? Although its not enabled in Hive, my FAT code also supports folder creation with file write/seek/append. You'd probably also want some kind of RTC on such a device so that the file stamps could be up to date. If you put a low end NXP LPC ARM chip (like in Harmony/Melody) on the PCB it could be the ROM/RAM as well as access the SD/microSD card. However, not many of those parts come in .1" pitch DIP (if any) so it all depends on if you want to go to a full/part surface mount solution.

Yes. The Aquarius OS has the ability to load ROM extensions from an unused 4K region of memory. This region was reserved for an Extended BASIC ROM in the Aquarius II, but the original Aquarius will also use it if it's there. As part of the Mini Expander II, I'm planning to include a field-upgradeable 512K OS ROM which will be banked into that 4K space. This will mean a lot of bankswitching, since we only have a 4K window to work with, but at least it will provide lots of space for the drivers and other support software the Mini Expander II will need (along with the original Extended BASIC features). I had already planned to include an RTC—a DS1307, most likely—so that shouldn't be a problem.

 

I'm torn on the idea of using an ARM chip. On the one hand, I recognize that it would make things easier, but on the other hand, I like the idea of having the Aquarius handle everything itself, from the SD card I/O to the filesystem drivers, without the aid of a modern coprocessor. Putting an ARM processor in the Aquarius seems too much like strapping a jumbo jet onto a child's pull-along wagon and claiming that I've made the wagon into an airplane. The Aquarius was a beautifully minimalist design, and I'd like to keep it that way if at all possible.

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Yes. The Aquarius OS has the ability to load ROM extensions from an unused 4K region of memory. This region was reserved for an Extended BASIC ROM in the Aquarius II, but the original Aquarius will also use it if it's there. As part of the Mini Expander II, I'm planning to include a field-upgradeable 512K OS ROM which will be banked into that 4K space. This will mean a lot of bankswitching, since we only have a 4K window to work with, but at least it will provide lots of space for the drivers and other support software the Mini Expander II will need (along with the original Extended BASIC features). I had already planned to include an RTCa DS1337, most likelyso that shouldn't be a problem.

:cool: I didn't realise they'd future proofed the Aquarius.

 

 

 

I'm torn on the idea of using an ARM chip. On the one hand, I recognize that it would make things easier, but on the other hand, I like the idea of having the Aquarius handle everything itself, from the SD card I/O to the filesystem drivers, without the aid of a modern coprocessor.

I understand the reluctance but if you think of it as being a super I/O device it starts to look more appealing in my opinion. Even more so, if you have PCB and case space constraints and limitations. It just becomes a way of cramming lots of functionality in a small space. I'm sure if these types of devices were available cheap enough back in the day, then they'd have been used in carts. Anything to make a system better and to have more bragging rights than its counterparts.

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I wouldn't be too worried about the superfont upgrade yet. I think there is still lots of mileage in Aquarius chunky vision :-D check out what's been churned out on the ZX81!!

 

 

:sad:

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I wouldn't be too worried about the superfont upgrade yet. I think there is still lots of mileage in Aquarius chunky vision :-D check out what's been churned out on the ZX81!!

Yep! Blocky looking has its own coolness factor :-

 

 

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I wouldn't be too worried about the superfont upgrade yet. I think there is still lots of mileage in Aquarius chunky vision :-D check out what's been churned out on the ZX81!!

 

 

That's true, but even on the ZX81 some high-res graphics can be achieved. And luckily we have color :grin:

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That's true, but even on the ZX81 some high-res graphics can be achieved. And luckily we have color :grin:

I believe as standard the ZX81 can do a pseudo hires, real hires needs some sort of modification ( I'm sure there's someone more knowledgeable who knows for sure) and there were a few character rom boards that some games supported.

 

Another thing is the Aquarius hasn't been hacked/ explored in the way the ZX spectrum has and there maybe bugs or unexplored features that can be exploited

With regards to video generation :-))

Edited by barnieg

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:sad:

I wouldn't be too worried about the superfont upgrade yet. I think there is still lots of mileage in Aquarius chunky vision :-D check out what's been churned out on the ZX81!!

Agreed. I'm sure we'll get reprogrammable characters; it just won't be through an upgrade board designed by me, if Bruce's efforts in that area are successful. But practically speaking, even after other options are available, any released Aquarius game must also support the built-in character graphics. The fact that we don't have SuperFont right now needn't hinder the development of new games.

 

Despite a few frustrating omissions, Mattel actually did a decent job of populating the default character set with a good mix of general-purpose game graphics, so we already have a lot to work with. Aquarius players may be tired of seeing the stock robot and running man graphics, but that's because Aquarius game programmers "back in the day" always tried to do games better suited for sprite-oriented machines, and there are only so many options in the Aquarius character set for creating players and missiles. There are many other types of games better suited to the Aquarius that have never been fully explored, but that we now have the freedom to explore in homebrew.

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I'm almost thinking out loud a little, so someone correct me if I am going of on a tangent.

 

It's a long time since I have done any real electronics but it would appear that the miniexpander is not that far off something like this:

 

http://lotharek.pl/product.php?pid=64for the spectrum (48k model)

 

How hard would it be to have a generic z80 "soundcard" with controller ports that plugged into an appropriate adapter?

 

 

One of the reasons I am thinking along these lines is economies of scale.

 

 

 

Barnie

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