Help with Kaiser's Highway Star repro

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lidnariq
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Re: Help with Kaiser's Highway Star repro

Post by lidnariq » Sat May 09, 2020 3:52 pm

If Holy Mapperel identifies it as UNROM, you've got something miswired. Mapper 312 does not map the PRG banking register at $8000-$FFFF, and UNROM does.

... I suppose it's possible that something's glitching due to the delay between M2 and /ROMSEL. If so, you could try adding a RC delay on M2 where it goes into the 74'138.

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Fisher
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Re: Help with Kaiser's Highway Star repro

Post by Fisher » Sat May 09, 2020 6:43 pm

lidnariq wrote:
Sat May 09, 2020 3:52 pm
If so, you could try adding a RC delay on M2 where it goes into the 74'138.
No luck either.
rat's nest
rat's nest
Could this rat's nest be the cause of such problems?

lidnariq
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Re: Help with Kaiser's Highway Star repro

Post by lidnariq » Sat May 09, 2020 7:06 pm

... maybe? I mean, the LS series parts probably want a bypass capacitor.

You could try replacing the bare wire to the 74'161's /CLK input with a twisted pair with one end tied to ground, to provide some isolation? But that rather feels like hoping for magic.

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Fisher
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Re: Help with Kaiser's Highway Star repro

Post by Fisher » Sun May 10, 2020 7:10 am

The back of the board even gives me some despair... LOL!!
Rat's mess
Rat's mess
The objective of doing this was to know if the logic would work.
Since lindnariq confirmed it's correct, I think I should try the game on it's "definitive" board.

The board I intend to use is from an old Brazilian "Futebol" game, a hack o AVE's Ultimate League Soccer.
It was given to me because it was glitched. I found later it had the CHR ROM damaged.
I think there's no problem using an 74'175 instead of a 74'174, I'll just try putting an 74'32 under it and use one of the gates to decode the mirroring register.
I'll need to slightly rewire the 74'138 to achive what I need.
Are all these assumptions correct?

lidnariq
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Re: Help with Kaiser's Highway Star repro

Post by lidnariq » Sun May 10, 2020 3:27 pm

Having found the ROM on CaH4e3's dumping site, it appears to write the mirroring control to $C0FF and the bank to $6000. There's a bunch of other writes around, but you could probably ignore /ROMSEL in the decoder and use A7 instead (so that $C0xx doesn't collide with APU registers)

zxbdragon
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Re: Help with Kaiser's Highway Star repro

Post by zxbdragon » Sun May 10, 2020 7:32 pm

Why not ask cah4e3 for the PCB diagram?

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Fisher
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Re: Help with Kaiser's Highway Star repro

Post by Fisher » Mon May 11, 2020 2:04 pm

lidnariq wrote:
Sun May 10, 2020 3:27 pm
ignore /ROMSEL in the decoder and use A7 instead
Thanks.
Should I put A7 on the input pins or on one of the enable pins?

To use it with the other board, I think I should insulate pin 3 and pull down pin 4 of the 74'138.
On the 74'175 side I think I should insulate pins 2,7 and 10 pluging them on the SMD 74'32 that I plan to put under the 74'175.
This should be enough to at least make the game boot and go to the title screen.

The 74'74 I'll try to put on the place of the NINA IC, with an SMD 74'00 under it.
This should give me enough work for a couple of days, I think.
Hope it works at the end.
zxbdragon wrote:
Sun May 10, 2020 7:32 pm
Why not ask cah4e3 for the PCB diagram?
I dropped him a mail that he kindly answered.
Unfourtunatelly he doesn't have some pictures nor the schematics of that board.

lidnariq
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Re: Help with Kaiser's Highway Star repro

Post by lidnariq » Mon May 11, 2020 2:21 pm

Fisher wrote:
Mon May 11, 2020 2:04 pm
Should I put A7 on the input pins or on one of the enable pins?
I'd put it on one of the '138's address lines. Otherwise you can't decode both registers at the same time.

A,B,C: A14, A13, A7 (in any order)
/E: R/W
+E: M2

Resulting mask: $6080. Check for $4080 → clock 74'74. Check for $6000 → clock 74'175.

krzysiobal
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Re: Help with Kaiser's Highway Star repro

Post by krzysiobal » Mon May 11, 2020 2:33 pm

Fisher wrote:
Thu May 07, 2020 6:05 pm

Code: Select all


                                                    74LS02
                                                 ____
          74LS138              74LS74   PPU A10--\   \     ____
         +---V---+            +------+            )   O----\   \
CPU A13-1|A0     |16---VCC---1|CLR  Q|5----------/___/      )   O---CIRAM A10
CPU A14-2|A1   O0|15---------3|CLK   |           ____  +---/___/
/ROMSEL-3|A2   O1|14  CPU D0-2|D     |  PPU A11--\   \ |         
/ROMSEL-4|/E0  O2|13   VCC---4|PRE /Q|6-+         )   O+
CPU R/W-5|/E1  O3|12-+        +------+  +--------/___/
     M2-6|E2   O4|11 |
        7|O7   O5|10 |                    74LS32 
    GND-8|8    O6|   |                     ____
         +-------+   |   74LS161  CPU A14--\   \
                     |  +---V---+           )   )---PRG A14
                     +-2|CLK  QA|14--------/___/
               CPU D0--3|A      |          ____ 
               CPU D1--4|B    QB|13--------\   \
               CPU D2--5|C      |           )   )---PRG A15
                       6|D      | CPU A14--/___/
                  GND--7|ENP    |          ____        
                 GND--10|ENT  QC|12--------\   \  
              CPU R/W--9|/LD    |           )   )---PRG A16
                 VCC---1|CLR    | CPU A14--/___/
                        +-------+
PPU-A10 and PPU-A11 should be exchanged.

It is interesting how they connected the 74138, because
* Provided ROM has bus conflicts,
* this 1M mask-rom has only one chip enable, so it must be enabled when /ROMSEL=0 and R/W=1

But that can't be done with using only one NAND gate and stealing additional OR gate for that purpose makes the mirroring register to occupy less than $8000-$ffff

lidnariq
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Re: Help with Kaiser's Highway Star repro

Post by lidnariq » Mon May 11, 2020 3:06 pm

krzysiobal wrote:
Mon May 11, 2020 2:33 pm
But that can't be done with using only one NAND gate and stealing additional OR gate for that purpose makes the mirroring register to occupy less than $8000-$ffff
There are two visible traces coming out of the 74'138 in Snacks's photo. Don't know if it's authentic to the original hardware, however.

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Re: Help with Kaiser's Highway Star repro

Post by krzysiobal » Mon May 11, 2020 3:30 pm

lidnariq wrote:
Mon May 11, 2020 3:06 pm
krzysiobal wrote:
Mon May 11, 2020 2:33 pm
But that can't be done with using only one NAND gate and stealing additional OR gate for that purpose makes the mirroring register to occupy less than $8000-$ffff
There are two visible traces coming out of the 74'138 in Snacks's photo. Don't know if it's authentic to the original hardware, however.
This is interesting, it means that 74138's Y0 (pin 15) and Y1 (pin 14) are used to control 74174's and 7474's clocks respectively.
But for $6000-$7fff A14, A13 and !ROMSEL are all ones, so they can't be connected to 74138's A/B/C.

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Fisher
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Re: Help with Kaiser's Highway Star repro

Post by Fisher » Wed May 20, 2020 8:13 pm

I had a little spare time this afternoon and got back to this.
I mounted the 74'138, 74'175, 74'32, the CHR RAM and the 74'00.
I used 1/4 of the 74'00 to invert CPU R/W and avoid bus conflicts.
I've followed lidnariq's instructions, the game booted straight to the car select screen and locked there.
What could be wrong?
Is the missing 74'74 doing this?
Maybe the SMD 74'32 is defective?

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Re: Help with Kaiser's Highway Star repro

Post by lidnariq » Wed May 20, 2020 10:58 pm

As far as I can tell, the game writes:
* cipher[bank] to $4A00+cipher[bank] (where those values range from 0xB2 through 0xCE)
* cipher[bank] to $6E36
* bank to $6000
* mirror to $C0FF

There is a plain UNROM mapper hack of the game present in GoodNES, which seems to work but has conspicuous glitches during the road, so I'd be surprised if incorrectly parsing the writes to $4Axx were causing a problem. I have to agree that hardware problems seem more likely right now?

zxbdragon
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Re: Help with Kaiser's Highway Star repro

Post by zxbdragon » Thu May 21, 2020 2:39 am

lidnariq wrote:
Wed May 20, 2020 10:58 pm
As far as I can tell, the game writes:
* cipher[bank] to $4A00+cipher[bank] (where those values range from 0xB2 through 0xCE)
* cipher[bank] to $6E36
* bank to $6000
* mirror to $C0FF

There is a plain UNROM mapper hack of the game present in GoodNES, which seems to work but has conspicuous glitches during the road, so I'd be surprised if incorrectly parsing the writes to $4Axx were causing a problem. I have to agree that hardware problems seem more likely right now?
goodnes Highway Star (J) [hM02] ,You seem to have posted PCB on the wiki.

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Re: Help with Kaiser's Highway Star repro

Post by Fisher » Thu May 21, 2020 4:33 am

zxbdragon wrote:
Thu May 21, 2020 2:39 am
goodnes Highway Star (J) [hM02] ,You seem to have posted PCB on the wiki.
Yeah, that was my first option, but I dropped it due to that "distracting" mirroring bug.
lidnariq wrote:
Wed May 20, 2020 10:58 pm
I have to agree that hardware problems seem more likely right now?
It's been a while I don't mess with debuggers, so I tried my "luck" with Nintaco's one.
I've set a breakpoint to writes on $6000-$7FFF, and found some to $6000, that I suppose is the bank register.
I also spotted many writes to $6E36 and a couple to $2000(?).
I don't know what they are and will ignore for now, since in these addresses A7 is high on $6E36 and A14 is low on $2000 so, the FF isn't clocked.
Hope that it's correct and these writes really doesn't matter to the bankswitching.

At powerup, it seems that the game selects bank 06 then go to 01 and then to 04, so the title screen appears.
After reset it selects bank 06 and then 05 so the car select screen appears.
Could it be a problem with the FF or gate that holds D0?

If I'm lucky I have only one FF/gate damaged and probably can rewire it to use the spare one(s) I have on the same IC.
Do these assumptions ever make sense for finding the defect or it's a problem with the register's decoding circuit?

Edit: My binary conversion was WRONG! A7 is 0 on 6E36.
Looks like the decoder is fine, I possibly have a bad flip-flop, since at least the game boots!!
Last edited by Fisher on Thu May 21, 2020 8:50 am, edited 1 time in total.

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