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Making an Eprom

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I posted this in the XB G.E.M. thread but it probably got lost in the chatter.


"A question has arisen on whether XB 2.8 G.E.M. can be loaded to a cartridge. The request is for "Something that can be loaded into an EPROM." What does this mean? How does that differ from the files I have posted that can be used as cartridges in Classic99 and the FinalGrom?"

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No it can't be just loaded on an eprom it needs a GROM as well as ROM you can use an UberGrom if it will fit in 128k of GROM and 512k of ROM

Sent from my LM-V600 using Tapatalk

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It might work in the HSGPL if the individual files were configured the right way. Nope too big.

Edited by atrax27407

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If it will load into the FinalGROM, it will work in an UberGROM, you just have to take the ROM portion and burn it into the 512K flash chip and then properly place the GROM files into the UberGROM. This process creates a complete image that can be copied, as you only need to build the image once. @acadiel has extensive experience creating UberGROM images, and may be willing to help here.


Note, I suspect that the original request was for a means to use the program in ROM-only mode, which isn't an option based on the need for GROM space in addition to ROM space--and in this case, you also don't have the option of lobbing the GROM stuff into the 32K space, as that is actually being used as User space by the program.

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Yep, my workflow for UberGROM carts from scratch (if I remember it correctly) - More details are here.



  1. Divide 512/ROM_SIZE (8K, 16K, etc)  to determine how many times I need to duplicate the ROM
  2. Duplicate the ROM that many times & concatenate it.  I wind up with a 512K ROM.
  3. Burn the 512K ROM to a 29F040 or 49F040


GROMs in 1284P:

  1. Divide GROM into 8,192 or 6,144 byte sections.  I always strip off the AA01XX header.
  2. Call them _G3, _G4, _G5, _G6, _G7 at the end
  3. Copy those files to a USB drive (HFA floppy image) with TI Image Tool  (make sure GROMCFG is also on this disk)
  4. Move my USB key to my GoTek attached to my TI-99/4A
  5. Run the built in EA on a new UberGROM
  6. Run GROMCFG and load the GROMs onto the UberGROM (GROMS 3-7 as applicable - do NOT Skip GK header as these are already stripped GROMs)
  7. Test it out
  8. If it works, dump the 1284P in a programmer and you'll get a 132K image for the 1284P. You can then distribute that to others with the 512K EPROM.


I believe that Tursi has ways of constructing the 1284P image from within Classic99, but I don't know what the method is.


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It's exactly what you're doing, I just run GROMCFG. In fact I thought I was the only person using GROMCFG and was quite salty about it. ;)


You enable UberGROM emulation in Classic99 by just defining a file to load in the INI with type 'U'. If you are building a new one from scratch, it can just be a dummy file. However, Classic99 doesn't emulate the embedded Editor/Assembler loader, so you /also/ need to include an EA GROM (or just use Playground to load it, which is easier now).


This is the config I was using:


name=Ubergrom test
; The UberGROM code load doesn't work today, but the U is needed
; to activate the emulation. Included is an E/A GROM relocated to
; >2000 so it can replace TI BASIC. A future version of Classic99
; will fix the UberGROM powerup emulation so that you can properly
; get into it. Copy the EA2K.BIN into the Classic99 mods folder.
; Do not load editor or assembler from this, they will not function.
; This is actually a part of my MPD project. ;)

I'm not sure if the comment there is still true (about the code load not working), but you'll notice that my U line is a dummy load anyway. The EA2K.BIN is, as the comment notes, Editor/Assembler running from TI BASIC space so it won't conflict with whatever you're building.




Once that much is in place, you can run GROMCFG, do the configuration and save the result all on the PC.


(Edit: Actually, I'm quite sure that comment is not true, cause I run some UberGROM configs from the INI without issue ;) )



Edited by Tursi

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On 9/17/2020 at 9:19 AM, Ksarul said:

I used the GROMCFG to build the Break Free cartridge file as well--so there are at least three of us using it, @Tursi


Ya know, it works very well, and once you get the hang of it, it's super easy to use.  @Tursi did an awesome job.

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