Chr-Ram boards. What am i missing?

A place that you can discuss reproduction of classic titles or "licensed-for-reproduction" homebrew for personal use.

Moderators: B00daW, Moderators

Forum rules
1. NO BLATANT PIRACY. This includes reproducing homebrew less than 10 years old, with the exception of free software.
2. No advertising your reproductions, with the exception of free software.
3. Be nice. See RFC 1855 if you aren't sure what this means.
Post Reply
noldor
Posts: 7
Joined: Thu Aug 17, 2017 6:50 am

Chr-Ram boards. What am i missing?

Post by noldor »

A big hello to all helpfull souls out there. :wink:

I have started putting translation patches on most of my japanese games and also making a bunch of repros. I have made about 30 games so far.
I have a 100% success-rate with sl-rom, tl-rom, nrom. My problem comes whenever a board uses chr-ram. Boards like un-rom and sn-rom.
I have a 100% fail-rate with every game that uses chr-ram so i have just come to the conclusion that i am doing something wrong and i can not figure it out. I use
a hakko fr-300 to desolder the PRG maskrom. I have tried games both with and without patching and they never work.

I use 27c2001 eproms. And wire them like this.

SN-ROM (bending up pin 1,2,24,30,31)
hole 1 -> pin 30
hole 24 -> pin 2
pin 24 -> pin 16 (ground)

TN-ROM (Bending up pin 1,2,24,30,31)
hole 1 -> pin 30
hole 2 -> pin 31
hole 24 -> pin 2
pin 24 -> pin 16 (ground)

SU-ROM (Bending up pin 1,2,24,30,31)
hole 1 -> pin 30
hole 24 -> pin 2
pin 24 -> pin 16 (ground)

Here are some pictures of some of the japanese carts i atempted to translate.

Dragon Warrior 3 on Dragon Quest 4 board (SU-ROM)
https://ibb.co/gbPx4v
Final Fantasy 1 (japanese rom with english patch) on original FF1 board (SN-ROM)
https://ibb.co/bDHvra
Final Fantasy 2 (japanese rom with no patch) on original FF2 board (SN-ROM)
https://ibb.co/gWG5ra
Final Fantasy 3 (Japanese rom with english patch) on original FF3 board (TN-ROM)
https://ibb.co/hZXOcF

I have used famirom to export the rom 1mb for use with my 27c2001 as i have done with all other (working) games.
All of the 4 samples above give a solid grey screen. I resoldered the original maskrom to the "final fantasy 3" board and that
worked fine so the board seems fine.

I have searched the forum and the rest of the web and i have drawn a blank. What am i doing wrong?
Is there any Nes/famicom wizard that knows the secret?
tepples
Posts: 22705
Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
Contact:

Re: Chr-Ram boards. What am i missing?

Post by tepples »

Do you also fail to build Holy Diver Batman for UN/SN/SU/TNROM? If it beeps Morse code at you, I can explain what went wrong.
noldor
Posts: 7
Joined: Thu Aug 17, 2017 6:50 am

Re: Chr-Ram boards. What am i missing?

Post by noldor »

Hello Tepples.
Thank you for the help.

I burnt the holydiverbatman testrom to a chip and soldered it to the FF2 SN-ROM board pictured above
in the exact same way that i had soldered FF2.
I get a short morse code response.
Excuse the low volume.
https://www.youtube.com/watch?v=LfvPMpQ ... e=youtu.be

I hope this tells you something important. :wink:
tepples
Posts: 22705
Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
Contact:

Re: Chr-Ram boards. What am i missing?

Post by tepples »

"This video is unavailable"
noldor
Posts: 7
Joined: Thu Aug 17, 2017 6:50 am

Re: Chr-Ram boards. What am i missing?

Post by noldor »

Oops, realy sorry.
It should be available now.
Thank you again for the help and the patience. :D
tepples
Posts: 22705
Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
Contact:

Re: Chr-Ram boards. What am i missing?

Post by tepples »

When Holy Diver Batman can't even ensure that it can draw to the screen, it falls back to beeping two or three letters in Morse code. The beeping here (... .._, dit dit dit - dit dit dah) is Morse code for SU, issued by finish_init_mmc1 in mapper_detect.s. This means the mapper detection portion of the test has detected MMC1 but has failed to switch to the second 2 Mbit half of the ROM to begin the rest of the test. (The code SU was chosen because this error is specific to SUROM and SXROM.) First I'd check continuity of the MMC1's CHR A16 output (pin 11) to PRG ROM A18, both at pin 31 and at hole 2.

Does SNROM, TGROM, TNROM, or UNROM work? What Morse code do they beep?
noldor
Posts: 7
Joined: Thu Aug 17, 2017 6:50 am

Re: Chr-Ram boards. What am i missing?

Post by noldor »

tepples wrote:When Holy Diver Batman can't even ensure that it can draw to the screen, it falls back to beeping two or three letters in Morse code. The beeping here (... .._, dit dit dit - dit dit dah) is Morse code for SU, issued by finish_init_mmc1 in mapper_detect.s. This means the mapper detection portion of the test has detected MMC1 but has failed to switch to the second 2 Mbit half of the ROM to begin the rest of the test. (The code SU was chosen because this error is specific to SUROM and SXROM.) First I'd check continuity of the MMC1's CHR A16 output (pin 11) to PRG ROM A18, both at pin 31 and at hole 2.

Does SNROM, TGROM, TNROM, or UNROM work? What Morse code do they beep?
The holydiverbatman rom that gave us the "SU" error code was soldered to a SNROM board from FF2.
I checked the MMC1 as you recommended and it has full continuity according to the following "diagram". Still greyscreen thou. :(

MMC1 (SNROM)
.--\/--.
......PRG A14 (r) <- |01 24| -- +5V
......PRG A15 (r) <- |02 23| <- M2 (n)
......PRG A16 (r) <- |03 22| <- CPU A13 (nr)
......PRG A17 (r) <- |04 21| <- CPU A14 (n)
......PRG /CE (r) <- |05 20| <- /ROMSEL (n)
...WRAM +CE (w) <- |06 19| <- CPU D7 (nrw)
......CHR A12 (r) <- |07 18| <- CPU D0 (nrw)
................n/c <- |08 17| <- CPU R/W (nw)
................n/c <- |09 16| -> CIRAM A10 (n)
................n/c <- |10 15| <- PPU A12 (n)
...WRAM /CE(w) <- |11 14| <- PPU A11 (nr)
...............GND -- |12 13| <- PPU A10 (nr)

I have also soldered a HolyDiverBatman rom into a TN-Rom and a SU-Rom.
The SU-Rom gives me a dead silent, solid, grey screen.
The TN-Rom gives me the following morse code.
https://www.youtube.com/watch?v=M0pZHhh ... e=youtu.be

Crossing my fingers that this leads to a breakthrough. I must be doing something wrong. As far as i know
a chr-ram repro using a 27c2001 should not be this difficult. Frustrating to have every chr-ram (unrom, tnrom, surom, snrom) repro fail when all
of my other repros work without any problem. :?
Grateful for the help Tepples.
tepples
Posts: 22705
Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
Contact:

Re: Chr-Ram boards. What am i missing?

Post by tepples »

The TNROM video is giving LB, which means trouble getting to the last bank. The SU code is similar. How are you splitting the PRG ROM from the header when programming the memory?

(It might be easier to look up the dits and dahs in a Morse code chart than to post a video to YouTube.)
noldor
Posts: 7
Joined: Thu Aug 17, 2017 6:50 am

Re: Chr-Ram boards. What am i missing?

Post by noldor »

tepples wrote:The TNROM video is giving LB, which means trouble getting to the last bank. The SU code is similar. How are you splitting the PRG ROM from the header when programming the memory?

(It might be easier to look up the dits and dahs in a Morse code chart than to post a video to YouTube.)

Haha! Yea that is probably true but i have a realy hard time with Morse. I can not differentiate the shorts from the longs so i would be looking up morsecode
blindly. So i really appreciate the help. ;)
I have also not found any chart that tells me the meaning of the two letters. I could not find that in the readme that comes with the holydiverbatman rom.

When i split the rom i just use famiROM and set it to create a 1 meg file that fits my 27c2001. famiROM does not have an option to strip the header so
that might be my problem. It has not caused problems with any "non" chr-ram game so i never thought about that. Would you recommend another
program to split the rom and create the prg.bin file?
noldor
Posts: 7
Joined: Thu Aug 17, 2017 6:50 am

Re: Chr-Ram boards. What am i missing?

Post by noldor »

hey, wait. I have been splitting the rom into 1Meg chr and prg but the 27c2001 is 2Megabits...
I resoldered FF2 with at 2mbit flashed eprom and sure enough.

When you said that i could not read the second bank and i looked at my last post i realised i have been treating the
27c2001 as a 1mbit rom..... :(
Damn do i feel stupid. Strange that the other repros work. On the other hand, i have not played them through. Should i worry
that they don't work all the way or is this a on/off situation??
tepples
Posts: 22705
Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
Contact:

Re: Chr-Ram boards. What am i missing?

Post by tepples »

As far as I'm aware, it'll usually be a can boot/can't boot situation. In this test ROM, I took pains to make it keep doing something when the wrong bank is switched in (hence WB, LB, SU error codes). An incomplete ROM for a real game should just crash early on because hardware init code is left out. This is especially true because with common non-multicart mappers on NES, the code executed first is at the numerically highest address.

I agree that Holy Diver Batman needs improved documentation. As of right now, the code meanings can be deduced from the source code. I'd list them all, but before I make any updates, I want to stop potentially angering Warner Bros.
noldor
Posts: 7
Joined: Thu Aug 17, 2017 6:50 am

Re: Chr-Ram boards. What am i missing?

Post by noldor »

tepples wrote:As far as I'm aware, it'll usually be a can boot/can't boot situation. In this test ROM, I took pains to make it keep doing something when the wrong bank is switched in (hence WB, LB, SU error codes). An incomplete ROM for a real game should just crash early on because hardware init code is left out. This is especially true because with common non-multicart mappers on NES, the code executed first is at the numerically highest address.

I agree that Holy Diver Batman needs improved documentation. As of right now, the code meanings can be deduced from the source code. I'd list them all, but before I make any updates, I want to stop potentially angering Warner Bros.
Thank you for the patience and your time. Sorry for being a dummy. I have successfully fixed all the chr-ram repros i had attempted and now the
successrate for those seem to be at 100%.
I built a small adaptor which made it possible to erase and reuse the eproms with the bent and cut pins. I will play through one of my earlier TL-ROM
repros and check if it runs all the way through. I will get back to you on that. ;)

Thanks again.
Post Reply