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Author Topic: Putting Near's (v1.2) Bahamut Lagoon translation on a cartridge  (Read 1248 times)

jaskamakkara

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Putting Near's (v1.2) Bahamut Lagoon translation on a cartridge
« on: September 30, 2021, 05:10:59 pm »
Hi all,

I recently put Near's excellent BL translation onto a real SNES cartridge. The game boots and runs seemingly ok (although the cut scenes are a little glitchy), but I am having problems with names and other text being loaded from memory not showing up properly.

Here is a link to a picture showing an example of the problem

Now, I have made many, many, many reproduction carts in the past so I am pretty confident I have wired it correctly (I also replaced the existing 64k RAM with a 256k RAM since apparantly this translation uses more RAM), but I am wondering if this ROM is simply incompatible with real hardware? The translation home page mentions people playing it with a flashcart, can that somehow improve performance? Also, one concerning line in the release notes for the patch is this:

"Player and dragon names are cached in memory, so they do not have to be rendered dynamically within menus."

This sounds like it might be related, any ideas?

I'd really appreciate any input on this one. Thanks all.

mziab

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Re: Putting Near's (v1.2) Bahamut Lagoon translation on a cartridge
« Reply #1 on: September 30, 2021, 05:24:38 pm »
One of byuu/Near's tricks was using SRAM (save ram) as extra RAM for the VWF scratchpad etc. When you say you expanded the RAM to 256kB, do you in fact mean SRAM? If so, it might be mapped to the wrong part of the memory map. Otherwise, you probably need to expand the SRAM. The size you mentioned suggests it's the latter case.

jaskamakkara

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Re: Putting Near's (v1.2) Bahamut Lagoon translation on a cartridge
« Reply #2 on: October 01, 2021, 02:20:41 am »
Interesting, thanks for your help. Yes I have added a 256k SRAM to the cartridge (it is a BJ3M so only comes with 64k), but it might be that I have wired it incorrectly, I will correct it and see if that helps.
« Last Edit: October 01, 2021, 03:24:31 am by jaskamakkara »

mziab

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Re: Putting Near's (v1.2) Bahamut Lagoon translation on a cartridge
« Reply #3 on: October 01, 2021, 03:08:19 am »
For what it's worth, this is the mapping bsnes-plus uses for the original ROM:

Code: [Select]
  <rom>
    <map mode='shadow' address='00-3f:8000-ffff'/>
    <map mode='linear' address='40-7d:0000-ffff'/>
    <map mode='shadow' address='80-bf:8000-ffff'/>
    <map mode='linear' address='c0-ff:0000-ffff'/>
  </rom>
  <ram size='2000'>
    <map mode='linear' address='20-3f:6000-7fff'/>
    <map mode='linear' address='a0-bf:6000-7fff'/>
  </ram>

And the one for the translation:

Code: [Select]
  <rom>
    <map mode='shadow' address='00-3f:8000-ffff' offset='400000'/>
    <map mode='linear' address='40-7d:0000-ffff' offset='400000'/>
    <map mode='shadow' address='80-bf:8000-ffff' offset='000000'/>
    <map mode='linear' address='c0-ff:0000-ffff' offset='000000'/>
  </rom>
  <ram size='8000'>
    <map mode='linear' address='20-3f:6000-7fff'/>
    <map mode='linear' address='70-7d:0000-7fff'/>
    <map mode='linear' address='a0-bf:6000-7fff'/>
  </ram>

So the original ROM had the standard 8kB SRAM and byuu expanded it to 32kB.

Looking at the memory map, another possible cause of your issues might be how the expanded ROM is mapped. Banks 40-7d contain the extra ROM data now rather than another copy as before.

256kB SRAM might also be overkill and clobbering something in the memory map.
« Last Edit: October 01, 2021, 03:40:27 am by mziab »

jaskamakkara

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Re: Putting Near's (v1.2) Bahamut Lagoon translation on a cartridge
« Reply #4 on: October 01, 2021, 03:28:49 am »
Nice, thanks for that extra info. I think the thing with banks 40-7D shouldn't be an issue since the console maps that area to ROM (with the /CART signal being low in these banks) so I think it should just work - the SNES doesn't know what it's looking at it just does what the ROM tells it to. Could be wrong but I am pretty sure it isn't a problem. I think the problem definitely lies with the SRAM being used as a scratchpad since I may have wired the SRAM incorrectly. I just found out that apparantly SRAM lines A13 and A14 on 256k chips (on HiROM carts) were connected to SNES A16/17, not A13/14 as I thought - I will correct this and see if it fixes the problem.
« Last Edit: October 01, 2021, 04:12:51 am by jaskamakkara »

Bonesy

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Re: Putting Near's (v1.2) Bahamut Lagoon translation on a cartridge
« Reply #5 on: October 01, 2021, 01:03:08 pm »
i was not aware we were allowing repro talk

jaskamakkara

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Re: Putting Near's (v1.2) Bahamut Lagoon translation on a cartridge
« Reply #6 on: October 02, 2021, 01:18:11 am »
Got it working by fixing the SRAM wiring, thanks for your help

KingMike

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Re: Putting Near's (v1.2) Bahamut Lagoon translation on a cartridge
« Reply #7 on: October 02, 2021, 01:40:36 am »
Glad you solved it but discussion specifically about building repros is not considered within the topic of this forum.
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