[BackBit cartridge - thoughts please]

I always welcome product suggestions over at forum.backbit.io. I tend to respond to peer pressure so if a lot of people all want the same thing I will certainly prioritize it. Know that I have a lot of irons in the fire, so if you want something don't just assume I won't do it.

 

I finished development on a MSX SCC audio adapter (it's like the existing adapter but has an extra chip on it). It will be available for sale in the near future. BackBit is not as compatible as UII+ on the C64 because it doesn't support the IEC port. This is mainly a design decision to focus on speed and ease of use. All EasyFlash releases up to 1MB are supported and include EPROM saving support, and more conversions are available all the time.

[BackBit cartridge on the Intellivision]

There have been major improvements in the firmware. I fixed an issue with signal debounce that makes RAM more stable. I added .ROM file flag support so it will interpret RAM sections & obey 8-bit and 16-bit RAM requirements. JLP is now supported to the extent that IntvBASIC uses it. If there are titles that use things like the random # generator and signed multiply/divide, that is a possibility to add later. Also I do plan at some point to add Flash ROM/persistent saving support.

[BackBit cartridge on the Intellivision]

The BackBit Pro Cartridge operates with 1MB of RAM available for instant retrieval. That can be mapped as ROM, RAM, whatever. For titles that have save states, the most straightforward implementation is to just have the game see it as regular RAM, and BackBit will save that to the SD card after the button on the cartridge is pressed to return to the menu. This is different than how a "real" cart would work, as it would save right away. But it will be functionally equivalent to a cart that had a battery backup. A game that has flash storage works differently, as it will typically have an API to access the FLASH ROM on the cart. This makes for much more coding work, and is something I generally avoid, because then I have to emulate a specific Flash ROM chip's method of reading and writing. It is much easier to just operate like a battery backed RAM. There is no real hardware difference between FLASH RAM AND FLASH ROM -- just that Flash ROM will not have a write-enable pin exposed.

[BackBit cartridge on the Intellivision]

12 hours ago, Caleb Garner said:

I don't know that game, but i would doubt it works at this time.  I know ram is being talked about for Chess and such.  I don't know how the rom was configured to work on the LTO..  does it know to write some chunk of data?  

 

I don't see any reason why it couldn't since it's still just SD storage which is persistent..  but i'm not sure how the rom would be written to claim some space on the sd card..  maybe this is some feature that comes with JLP?

 

@evietron do you know if there is a way to achieve this?  to have a game know how to write save data to a file on the SD card?   This seems outside the typical capabilities of an typical intellivision game. 

Saving is possible, in theory, but the specific kind of saving has to be implemented. First, I will add RAM support, then I will make saving the RAM an option, then once all that works, I can look into supporting a saving method that does not use RAM.

[BackBit cartridge on the Intellivision]

I was trying to get some more input for the ECS format. I'm thinking that 2K banks might be more universal than 4K banks?

 

As for the next batch of carts I'm waiting on chips and last I heard they are short of raw materials, and that's the main holdup.

[BackBit cartridge on the Intellivision]

On 9/18/2022 at 8:09 AM, Caleb Garner said:

So I've got the latest firmware that relates to intellivision..  in fact a little past it.  1.4.5 but with a lot of great help from @mr_me we were able to figure out how to get working roms.  

 

The only game (aside from chess / triple play which are due to lack of ram support, and well ECS games for obvious reasons) was Atlantis.  It plays but the clouds don't look right..  very odd.  other imagic games play fine it's just this one..

 

 

 

This has been fixed in latest firmware. It was caused by the auto INTV II patching.

[Intellivision ECS file format]

Is there a somewhat standardized format for Intellivision other than BIN+CFG (too vague) or LUIGI (too detailed) that can play an ECS title?

 

It would be nice if there were a single binary file format that was easy to parse by an embedded device.

 

I was considering just making my own, but I wanted to open up to community input.

[BackBit Pro Cartrdige for the TI-99/4A]

I will support any standardized community format as long as it can be contained in a single binary file, and doesn't have an extensive amount of parsing required. If you want to have a custom file extension to describe what format a raw binary is in, I am okay with that.

 

As I have a multitude of projects for different systems in development at once, the best place to ask questions and post feature requests is on the BackBit Forum (forum.backbit.io).

[Which 2600 Games DON'T work on a 7800?]

Thanks Trebor for your input. The difficulty switch worked on Masters of the Universe. For Congo Bongo, if I wait for 0xfffx access after reset before serving ROM then it works. Funny how it's just that one game, but I suspect it might have something to do with 2600 cart detection code and the bus interfering with that. So that means BackBit now supports all known original titles for 2600/VCS.

[Which 2600 Games DON'T work on a 7800?]

Two stumpers for me on a later generation 7800 are Congo Bongo and Masters of the Universe. Congo Bongo crashes on load, and Masters of the Universe shows the title screen but won't move the ship. These are using my BackBit cart. When I run these with the same exact setup on a 2600 Jr they work fine.

[Now Available: 512KB memory expansion for Tandy CoCo 3]

I created a limited run of these memory 512KB memory expansions for the Tandy Color Computer 3: https://store.backbit.io/product/memory-expansion-coco3/

 

Purchase link is on the store page, and they are ready to immediate shipment from the USA.

 

Thanks for your interest.

[BackBit Pro Cartrdige for the TI-99/4A]

If you need a specific title working, feel free to inquire on the BackBit Forum (forum.backbit.io). I actively update the firmware so really anything is possible (that doesn't require the side port).

 

I also recently made a small batch of a simple 32K RAM expansion that can be tacked on to your machine:

https://store.backbit.io/product/32k-memory-expansion-for-ti-99-4a/

 

As for the file format, there is nothing custom at all on the BackBit except the fact that it requires titles to be contained in a single file, which I think makes titles a lot easier to navigate and organize.

 

If you have any C G or BIN file it will load that with no fiddling, or if you have C+D or C+D+G, or C+G, those can be combined easily:

copy /b file.c+file.d+file.g file.bin

 

It will auotomatically detect where the GROM is (typically after 8K or 16K of ROM).

 

Unfortunately the BackBit Cartridge is now sold out until 2023, but I am taking pre-orders for the next batch :-)

[BackBit Pro Cartrdige for the TI-99/4A]

7 hours ago, retroclouds said:

 

Wonder if the menu system is running on the home computer side or if most of it is running on the backbit side and home computer side is used for output and input.

 

 

The client on the vintage machine has a very basic browser that can handle 1 screen of information. The rest happens on the cartridge end.

[BackBit Pro Cartrdige for the TI-99/4A]

Any amount of ROM up to 1MB should be no problem (and can be combined with 40K GROM using the aforementioned method).

[BackBit Pro Cartrdige for the TI-99/4A]

I don't see why not. The only question would be where you are going to save your BASIC programs.

[BackBit Pro Cartrdige for the TI-99/4A]

For the record, BackBit DOES support GROM, up to 40KB. You must use extension G.

 

It also supports ROMs combined with a GROM (i.e. the CG/CDG format). For this, use extension BIN/ROM/C. Append binaries in the order C,D,G.

 

For normal & multi-bank ROMs, use extension BIN/ROM/C.

[BackBit Pro Cartrdige for the TI-99/4A]

The BackBit cartridge supports up to 1MB of ROM using the banking scheme of writing to 6000,6002,6004, up to 60fe.

[Astrocade SD cart]

1 hour ago, 128Kgames said:

I'll be packing up the bulk of my Bally / Astrocade collection this weekend, not sure but I may have something you can work with.  The thing with these systems as I'm sure you've found is the ones that work are, well, expensive.  But let me see what I can come up with and then we can go from there.  

 

I see you have adapters for the Color Computer 2 and 3 - any chance you'll support the original TRS-80 Color Computer?  My uncle a former Raytheon Engineering Manager had one when I was growing up and was kind enough to give it to me during the pandemic, but I've yet to set it up.  

Understood! I just thought it might be possible to help somebody revive a "dead" system. Who knows, maybe some of those custom IC's could do with modern replacements to patch up some sad broken systems.

 

There's no reason the Color Computer 2/3 adapter wouldn't work with the original CoCo, as the cartridge pinout is the same. I just haven't tested it. Some memory locations may be different, or may not be!

[Astrocade SD cart]

Thanks for everybody's interest.

 

The offers I've received so far and systems on the open market are a bit out of my price range at the moment. I'm open to trades for a BackBit cart & other accessories I sell.

 

I'm fine with systems that are in need of work or with cosmetic defects.

[Astrocade SD cart]

10 hours ago, 128Kgames said:

I've never been a fan of using the expansion port for anything but RAM or a computer expansion module, and certainly not a multicart.  In fact I shot down the idea when I started the 128k Project 10+ years ago to build the first bankswitching cart for the Astrocade.  This fit into a standard cart shell and required no external power.  

BackBit does not use standard cart shells due to the adapter system. One notable advantage of using the expansion port is that you have access to the reset pin, which allows you to switch games without physically turning the system off.

 

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As your device is handling much more than just a bankswitched cart I get the need to use it (expansion) but aesthetically I hate the thought of anything hanging off the back.

My adapter would attach at a right angle, so it would be more like hugging the machine than hanging off.

 

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Maybe someone with 3D printing experience can come up with a cover for case hole for when your device is disconnected.

Not a bad idea. I could try and come up with something.

 

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I'll look through my collection to see if I have any consoles you can use.

It would be much appreciated!

[Aquarius, is there a flashcart?]

Yep, I made the Aquarius adapter for BackBit. So if you get the BackBit cartridge w/ Aquarius adapter you have a straightforward solution. It will load carts & program files and supply 32K RAM expansion. Cassettes can be converted to program files. There is potential for a bankswitching option but I haven't seen any programs that need such a thing yet.

[Astrocade SD cart]

I've received some interest, and I'd like to get my BackBit multi-system cartridge working on the Bally Astrocade.

 

Feature-wise, it would plug into the expansion port on the back, have a USB port or jumper option for power, play games off a MicroSD card, and it would support RAM expansion & bank-switching ROM.

 

The actual development of the adapter & software wouldn't take much time but I need to get my hands on a system. I'm even open to taking on one in poor cosmetic condition and/or that needs some repairs. I can trade a BackBit cart w/ adapter and possibly some of my other products as well.

[BackBit cartridge on the Intellivision]

1 hour ago, Lathe26 said:

I think you mean that the Intellivoice must be tolerant to having those 3 pins grounded by a non-voice cartridge since the doc is the specification for the Intellivoice itself.  I accidentally type "Intellivision" sometimes when I meant to type "Intellivoice".  Short version is that not connecting these 3 pins to ground in the BackBit and leaving them floating should be fine.

Yes, indeed!

[BackBit cartridge on the Intellivision]

4 minutes ago, Lathe26 said:

Oops, I missed this comment before I posted my long comment. 

 

It should be fine to leave pins 16/18/20 open.

Thanks for the confirmation. Looking at the schematic for the Intellivision, pins 14..28 are all shorted together. It would appear that the Intellivoice repurposed those 3 pins for what is plugged into it. As a voice activated cartridge will leave those 3 pins open, but not actually do anything with them, there doesn't seem to be any harm to leave them floating.

 

If you look at this document, page 13 states that the Intellivision must be tolerant to those 3 pins being connected to ground, but also implies that they don't have to be. This document is what originally tipped me off that these 3 pins might be the issue with not getting any voice.

[BackBit cartridge on the Intellivision]

I figured it out. I needed to disconnect pins 16/18/20 on the cart from GND. Is there any adverse affect for not grounding these pins on a non-voice ROM?