Devcart: help with switch for Vertical /Horizontal mirroring

Devcart: help with switch for Vertical /Horizontal mirroring
by on (#7728)
As mentioned in previous posts, I'm working on my (first) dev cart, an NROM one.

I was looking around on Romlab, and found this picture:

Image

It's not a whole lot of help because I'm new to most electronics / soldering, which is why I'm going for the NROM first (with no re-wired pins, etc).

I found this on the old message board:

Subject Re: NES DevCarts: NROM, more?
Posted by philtulju
Posted on 5/14/03 1:19 PM
From IP 63.251.238.194

---snip---

I added some wire and a jumper to accomodate horozontal or vertical mirroring, wiothout having to solder. There are 2 "pseudo-switches" on the board, for the two mirroring options, which are connected with a solder blob. Desolder this to access the three leads you need for a switch or jumper.

---snip---

If anyone could simplify this even further, I would appreciate it. I seen the H / V swith on the NROM board with the blob, and I'm curious how I could install a swith.

Thanks in advance,

NC

by on (#7731)
That's exactly what I'm planning to do with my CNRAM cart (for use with CopyNES) - connect the outer pins on your switch to PPU A10 and PPU A11 and connect the center pin to VRAM A10, and you should be all set.

by on (#7736)
Now I'm a bit confused. I thought I would have to solder wires near the actual V / H on the chip itself (as pictured).

I am using an SMB cart, and it only had three chips to begin with: PRG, CHR, and one 16 pin chip on the left.

I looked for VRAM information on NESDEV / romlab, and it shows a 28 pin chip.

Just curious where PPU A10/11 is, and the VRAM A10.

Thanks,

NC

by on (#7737)
PPU A10, PPU A11, and VRAM A10 are all located at the mirroring pads. The signal which is common to BOTH sets of pads is VRAM A10 (as shown in the picture above), while the others are PPU A10 and PPU A11.

by on (#7738)
Quietust wrote:
PPU A10, PPU A11, and VRAM A10 are all located at the mirroring pads. The signal which is common to BOTH sets of pads is VRAM A10 (as shown in the picture above), while the others are PPU A10 and PPU A11.


That clears it up. Thanks for the information.

NC

P.S. - Is that covered somewhere in a document on the main site?

by on (#7753)
I just created one. Here is a picture of one I made for Popeye:


Image

Notice the small oval hole in the top left corner. There is a small switch for the H/V mirroring.

by on (#7754)
Nice, thanks!

Got a pic of the inside?

NC

by on (#7760)
OK.

Here is a clean version of a CNROM cart where I cleaned and sanded the edges:

Image

Here is the inside:

Image


Image

Here is a closeup of the H/V switch, The middle wire is the common and the other two wires go to H and V.

Image

I am running a Panesian Bubble Bath Babes to play on my NES. I can't afford the real thing so this is the next best thing.

-CFB

by on (#7767)
Cool, thanks! :)

NC

by on (#7826)
Also, since I don't think it's been said yet, the type of switch you'll probably want is a SPDT (single pole, double throw).

by on (#7831)
Memblers wrote:
Also, since I don't think it's been said yet, the type of switch you'll probably want is a SPDT (single pole, double throw).


Thanks. From looking at the pics, and then staring at switches at Radio Shack, I took a chance and bought them yesterday. :)

NC

by on (#7832)
I used a Double Pole Double Throw but I only wired one side. I had an extra switch in the old parts bin.

I also used 2 32 pin socket but I only really needed 28 pins since I am using 27C256 eproms. I didn't have the 28 pin socket so I improvised. I pulled out the extra 4 pins on the 32 pin sockets and soldered it to the board. The sockets lined up tightly but it worked.

You will notice that the eproms are aligned down. Any, it works like a champ.

by on (#7833)
I meant to say the the eproms are aligned up and the bottom 4 pins of the sockets are unused.

by on (#7834)
ChimFolkbutter1 wrote:
I used a Double Pole Double Throw but I only wired one side. I had an extra switch in the old parts bin.

I also used 2 32 pin socket but I only really needed 28 pins since I am using 27C256 eproms. I didn't have the 28 pin socket so I improvised. I pulled out the extra 4 pins on the 32 pin sockets and soldered it to the board. The sockets lined up tightly but it worked.

You will notice that the eproms are aligned down. Any, it works like a champ.


I did notice that the sockets were 32 pins. Glad to see it worked anyway. When the rest of my shit arrives in the mail I'll let you know how mine turns out.

NC

by on (#8152)
Today I made a CNROM cart, and it works fine. However, I'm having trouble with the switch. I used a SPDT switch. First I soldered one wire to each of the three posts. I took the left wire, and connected to the H. The right wire went to the V. The middle wire connected to each of them. I made a quick pic to show you how I did it. I didn't have stranded wire, so I laid the one wire across the other two, and soldered it down (like it looks in the picture). I'm not sure what I did wrong, but it didn't work. When I booted a game, the graphics were garbled - no matter which position the switch was in. I desoldered it and set it back to H mapping, and now the cart works fine.

Any help would be appreciated, thanks!

NC

Image

by on (#8154)
I dunno, but you don't need to solder the common pin to both pads. They should be connected by a trace on the board already. Though I suppose it shouldn't hurt anything.