evietron

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.

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.

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.

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.

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.

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

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.

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).

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.

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.

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.

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 :-)

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.

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

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

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.

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

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!

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.

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. My adapter would attach at a right angle, so it would be more like hugging the machine than hanging off. Not a bad idea. I could try and come up with something. It would be much appreciated!

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.

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.

Yes, indeed!

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.

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?