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Need a little help with the 139
Posted: Thu Jun 20, 2013 9:50 pm
by klonoa
Hey Guys.
I'm trying the make a brutal mario world (witch is 4MB)
But the slave cart (world league basketball) i used only had had one 1MB mask rom so i cut both traces leading to the 139
and wired the extra two address lines to my eprom.
But what to do with the decoder now?
My instinct told me to use a21 and a22 instead of a20 and a21
But that didn't work.
Any help?
Re: Need a little help with the 139
Posted: Thu Jun 20, 2013 11:15 pm
by whicker
yeah, fix that instinct bug...
Okay, no really. seriousness... it wasn't that bad of an assumption.
What is the size of the (presumably Flash ROM?) chip that is holding the 4 MB (32 megabits) of program?
Is it just one gigantic 4 MB chip, or are there multiple chips?
To leave out that key bit of info is to miss the point of address decoding. So, how many ROM chips?
Also, I and I think others will try to help, but it's hard to give exact information on how to turn random board A, into hacked board B.
Re: Need a little help with the 139
Posted: Thu Jun 20, 2013 11:26 pm
by Markfrizb
Save yourself a lot trouble and use a different host cartridge like college slam baseball or one of the many lo rom 32m capable carts with a mad1 decoder. It'll be much easier to alter.
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 11:53 am
by klonoa
Markfrizb wrote:Save yourself a lot trouble and use a different host cartridge like college slam baseball or one of the many lo rom 32m capable carts with a mad1 decoder. It'll be much easier to alter.
I normally would have done that but i got it all wired up already.
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 11:55 am
by klonoa
whicker wrote:yeah, fix that instinct bug...
Okay, no really. seriousness... it wasn't that bad of an assumption.
What is the size of the (presumably Flash ROM?) chip that is holding the 4 MB (32 megabits) of program?
Is it just one gigantic 4 MB chip, or are there multiple chips?
To leave out that key bit of info is to miss the point of address decoding. So, how many ROM chips?
Also, I and I think others will try to help, but it's hard to give exact information on how to turn random board A, into hacked board B.
I use one 4MB (32mbit) eprom.
No more.
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 6:54 pm
by whicker
At 4 MB, you don't really need an address decoder.
I don't have enough information about both games,
Does college slam basketball have a save battery?
Does college slam basketball use the LoROM, or HiROM mapping?
Assuming college slam basketball is LoROM and has save memory...
For the flash chip:
You just assert /CE when /ROMSEL is low and A15 is HIGH.
/CE LOW WHEN BOTH /ROMSEL is low AND A15 is HIGH
/CE = ROMSEL=0 AND A15=1
simplifying:
Chip Enable = /ROMSEL OR NOT A15
/OE of the flash chip is the /CPURD signal.
for the SRAM, you shouldn't have done anything with the 74139. It's in the spot it needs to be already, other than not using the /CS signal it generated for the 1 MB ROM that was in there before.
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 7:03 pm
by klonoa
whicker wrote:At 4 MB, you don't really need an address decoder.
I don't have enough information about both games,
Does college slam basketball have a save battery?
Does college slam basketball use the LoROM, or HiROM mapping?
Assuming college slam basketball is LoROM and has save memory...
For the flash chip:
You just assert /CE when /ROMSEL is low and A15 is HIGH.
/CE LOW WHEN BOTH /ROMSEL is low AND A15 is HIGH
/CE = ROMSEL=0 AND A15=1
simplifying:
Chip Enable = /ROMSEL OR NOT A15
/OE of the flash chip is the /CPURD signal.
for the SRAM, you shouldn't have done anything with the 74139. It's in the spot it needs to be already, other than not using the /CS signal it generated for the 1 MB ROM that was in there before.
thanks for the info but originally the 139 wasn't connected to romsel or a15 but to a20 and a21.
I'll post the original pinout later and you'll see what i mean.
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 7:21 pm
by qwertymodo
whicker wrote:At 4 MB, you don't really need an address decoder.
I don't have enough information about both games,
Does college slam basketball have a save battery?
Does college slam basketball use the LoROM, or HiROM mapping?
Assuming college slam basketball is LoROM and has save memory...
College Slam is
SHVC-1A3M-30, so MAD-1 (supports 32Mbit), 64K SRAM w/battery, LoROM.
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 7:26 pm
by klonoa
qwertymodo wrote:whicker wrote:At 4 MB, you don't really need an address decoder.
I don't have enough information about both games,
Does college slam basketball have a save battery?
Does college slam basketball use the LoROM, or HiROM mapping?
Assuming college slam basketball is LoROM and has save memory...
College Slam is
SHVC-1A3M-30, so MAD-1 (supports 32Mbit), 64K SRAM w/battery, LoROM.
i didn't use that game. i used world league basketball
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 9:40 pm
by qwertymodo
klonoa wrote:i didn't use that game. i used world league basketball
You sure? I can't find World League Basketball anywhere, including
byuu's database, which leads me to believe you're mistaken, because byuu's database should be 100% complete for all NTSC-U releases... and I really doubt byuu would be missing a dumb sports game
World League Soccer, maybe? In any case, what really matters is the PCB ID (probably SHVC-1A3M-XX).
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 9:48 pm
by klonoa
qwertymodo wrote:klonoa wrote:i didn't use that game. i used world league basketball
You sure? I can't find World League Basketball anywhere, including
byuu's database, which leads me to believe you're mistaken, because byuu's database should be 100% complete for all NTSC-U releases... and I really doubt byuu would be missing a dumb sports game
World League Soccer, maybe? In any case, what really matters is the PCB ID (probably SHVC-1A3M-XX).
this one:
witch is called NCAA basketball in the usa i just found out XD
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 10:05 pm
by klonoa
Re: Need a little help with the 139
Posted: Fri Jun 21, 2013 11:25 pm
by qwertymodo
Ah, PAL explains it. byuu's database is NTSC-U only so far. You caught an unlucky break, since that game also comes on a 1A1M PCB, which would have supported 32Mbit without modification...
Re: Need a little help with the 139
Posted: Mon Jun 24, 2013 5:09 pm
by klonoa
here are the setups that i tried so far
Code: Select all
__ __
SNES #49 |01\/16| +5V
A21 |02 15| NC
A20 |03 14| A19
ROM /OE |04 13| RESET
NC |05 12| NC
NC |06 11| NC
NC |07 10| NC
GND |08 09| RAM /CE
------
result: I can hear the nintendo sound and a random sound effect after it. no image
Code: Select all
__ __
SNES #49 |01\/16| +5V
A22 |02 15| NC
A21 |03 14| A19
ROM /OE |04 13| RESET
NC |05 12| NC
NC |06 11| NC
NC |07 10| NC
GND |08 09| RAM /CE
------
result: the nintendo logo comes on with the sound efect but stays there.
Code: Select all
__ __
SNES #49 |01\/16| +5V
A22 |02 15| NC
A21 |03 14| A20
ROM /OE |04 13| RESET
NC |05 12| NC
NC |06 11| NC
NC |07 10| NC
GND |08 09| RAM /CE
------
result: nothing.
any idea's?
Re: Need a little help with the 139
Posted: Mon Jun 24, 2013 8:34 pm
by whicker
none of those correctly deal with the A15 low = backup SRAM, A15 high = cart ROM
this is especially important for that huge 4 MB flash size.
i'm sure the original wiring for the 74139 could have gotten lazy and omitted A15, because the 1 MB ROM could be made to not overlap into the SRAM space, and the SRAM in ROM space would not have mattered.
without accounting for A15, the backup SRAM and the uppermost quarter of ROM overlaps.