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PostPosted: Sat Jul 11, 2015 11:54 am 
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So I found out the hard way that a tlsrom (Mapper 118) board does not behave the same as a tlrom (mapper 4) board. They both contain a mmc3 mapper though.

I did not catch the mapper 118 in the beginning, I was only looking at the mmc3.

In my searching I have found this.

"The CHR A17 line connects directly to CIRAM A10 line instead of MMC3's CIRAM A10 output, to compensate for the MMC3's lack of single-screen mirroring"

http://wiki.nesdev.com/w/index.php/INES_Mapper_118

I seem to be missing something as I have traced these lines and they do not appear to be directly connected. I even do a continuity test on the 2 and nothing.

I have used this document for the mapper pinouts.

http://nesdev.icequake.net/rom.txt

I assume when looking at the mapper and the lettering right side up on lower left is a circle in chip corner that that marks pin 1. So according to what I am reading mapper pin 12 should have a direct connection to mapper pin 4 but they don't have continuity.

This is driving me insane. Maybe this board can't be used.


Last edited by icemanxp300 on Wed Jul 29, 2015 10:28 pm, edited 3 times in total.

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PostPosted: Sat Jul 11, 2015 2:33 pm 
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icemanxp300 wrote:
So according to what I am reading mapper pin 12 should have a direct connection to mapper pin 4

No, those two pins should not be connected.

Here is a slightly better MMC3 pinout, and here are the cartridge connector pinouts. You only need to be concerned with MMC3 pins 10 and 12, and the pin for CIRAM A10 on the cartridge connector.

To convert TLSROM to TLROM, you need to disconnect MMC3 pin 12 from CIRAM A10 and connect MMC3 pin 10 instead. If your game has 256KB of CHR-ROM, you'll also need to connect MMC3 pin 12 to CHR-ROM A17.


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PostPosted: Sat Jul 11, 2015 3:33 pm 
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Ok so I cut the trace from mmc3 pin 12 to the corresponding cartridge pin CIRAM A10 (15 over from left to right). I then soldered a wire from CIRAM A10 to mmc3 pin 10.

My new chr is indeed 256 so I ran a wire from mmc3 pin 12 to pin 30 of my am27c020 as pin 30 is A17 on the chr. Still does not work correctly.

Here is a pic.

Attachment:
100_9200.JPG
100_9200.JPG [ 2.32 MiB | Viewed 3430 times ]


...


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PostPosted: Wed Jul 29, 2015 10:29 pm 
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Just wondering if I should even bother wasting my time using these chips on snes carts?


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PostPosted: Fri Jul 31, 2015 6:50 pm 
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icemanxp300 wrote:
Just wondering if I should even bother wasting my time using these chips on snes carts?


With 27c160's? They are the only way you will get more than 1mb with a single chip unless you use TSOP. 27c160's are great
cause all you have to do is shift over 1 address line and use D15 as A0. D0-D7 are used and the rest of the data lines you just
float. By hand it's many wires unless you have an adapter board designed and printed.


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PostPosted: Tue Aug 18, 2015 7:47 am 
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nintendo2600 wrote:
icemanxp300 wrote:
Just wondering if I should even bother wasting my time using these chips on snes carts?


With 27c160's? They are the only way you will get more than 1mb with a single chip unless you use TSOP. 27c160's are great
cause all you have to do is shift over 1 address line and use D15 as A0. D0-D7 are used and the rest of the data lines you just
float. By hand it's many wires unless you have an adapter board designed and printed.


Hey, this is another way you can do it:
Image

"No rewiring required", no address line re-ordering and it work with 27C322, for example.
But certainly it's cheaper to use a 27C160 with /BYTE pin and reorder the address lines.


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PostPosted: Tue Aug 18, 2015 11:36 am 
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Not only is it cheaper to use to 27c160 but also less wires needed.


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PostPosted: Tue Aug 18, 2015 12:29 pm 
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But is it cheaper to use one 27C322 or two 27C160?


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PostPosted: Tue Aug 18, 2015 2:16 pm 
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tepples wrote:
But is it cheaper to use one 27C322 or two 27C160?


A 27C160 will cost more simply because it offers byte mode. Cost more than twice as much as 27C322. So making that circuit will lower your cost in the long run. Because you get twice as much memory from just one chip.


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PostPosted: Wed Aug 19, 2015 6:45 am 
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Ice Man wrote:
Not only is it cheaper to use to 27c160 but also less wires needed.


Well at least 2 people have posted who know the wiring now. Could I please have a diagram or is it top secret :)

How about I try and someone help me on what I don't understand?


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PostPosted: Wed Aug 19, 2015 6:54 am 
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icemanxp300 wrote:
Ice Man wrote:
Not only is it cheaper to use to 27c160 but also less wires needed.


Well at least 2 people have posted who know the wiring now. Could I please have a diagram or is it top secret :)

How about I try and someone help me on what I don't understand?


It's simple.

Image

The /BYTE pin is used to select the chip mode. While in 8 bit mode, the pin "D15" is used as A0, A0 through A19 are shifted by one so A0 becomes A1, A1 becomes A2 and so on.

D8-D14 are left unconnected.

See, no mystery. But you can't do that with the 27C322 because it has no /BYTE pin. You need the circuit I posted for that one.


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PostPosted: Wed Aug 19, 2015 7:41 am 
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Oh wow, I had no idea that happened. Ok so now before I post my wiring does swap bin still apply to this chip?

NM wasabi does not give the option to swap bin anything but a 27c801. I'll see what I can come up with on this new info.


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PostPosted: Wed Aug 19, 2015 8:40 am 
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So basically the whole chips still needs to be rewired anyhow. After moving the pins like you said you are left with this.

Attachment:
m27c160 pins moved.jpg
m27c160 pins moved.jpg [ 102.19 KiB | Viewed 3224 times ]


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PostPosted: Wed Aug 19, 2015 8:47 am 
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The idea with the two extra TTL chips make it so you can put bigger chips without any rewiring.

But if you're not going to ever need more than 2MB, yeah that's about it. Remember, you leave Q8 to Q14 unconnected.


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PostPosted: Mon Aug 31, 2015 12:08 pm 
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EDIT: And Q = D


Attachments:
27c160 to snes mask.png
27c160 to snes mask.png [ 197.41 KiB | Viewed 3139 times ]


Last edited by nintendo2600 on Mon Mar 06, 2017 12:18 pm, edited 2 times in total.
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