Shared Projects by ziggy587

So far only tested with an 8Mb game on a 29F800 in a 32-pin socket, and found to work. It should work fine with a 29F160 since the only difference is one additional address pin.

This installs on the backside of a mask ROM. You must cut/isolate the /OE pin on the mask ROM and tie it to Vcc.

This adapter is made to work on both 32-pin and 36-pin mask ROM sockets. If using on a 32-pin socket, you will most likely have to cut off the 4 pins for clearance. You could score both sides with a utility knife or X-Acto blade and then snap it off, or use small flush cutters.

If you are using a 29F160 on a 32-pin socket, you will have to use a jumper wire for A20.

J1 connects /OE from the mask ROM socket to the TSOP chip, so close it if you are only using a single TSOP chip. If you leave J1 open, then you can use the /OE pad on this adapter to connect where ever you need it.

J1 is an 0603 resistor pad. You can use a 0-ohm resistor to close/bridge it, or a small bit of wire, or a trimmed leg from a through hole resistor or capacitor. I though the 0603 pad would be easy to close with a solder blob, but as it turns out, it’s not. The next revision of this board will have a proper jumper pad that is meant to be closed with a solder blob.

C1 is for an 0603 0.1µF capacitor.

Don’t forget to isolate the bottom to prevent shorts.

This is a simple circuit that will turn on an ATX power supply using a momentary switch. I made this specifically to use an AT style motherboard in an ATX case, however, you could use this generically in any case that you want to turn an ATX PSU on/off using a momentary switch.

The mounting hole is sized to fit a 6-32 screw so that you can mount the board using a standard motherboard standoff.

I’m using one of those common AT-to-ATX power adapters, which already breaks out the ground and PS_ON wires. If using one of these adapters, you will most likely have to add a pin/wire for the +5VSB signal.

A parts list is silkscreened on the back of the PCB. Resistors and capacitors are 0805 size. You can use standard 2.54mm single row pin headers for the switch and PSU connections.

This has been tested using an AT motherboard and ATX power supply for several hours and found to work as intended. But as always, use at your own risk.

This circuit was taken from a post found on Stack Exchange. More info can be found here: https://electronics.stackexchange.com/questions/186841/momentary-button-as-switch

UNTESTED! But should work fine, since there’s not much to it.

This is a small adapter for a 74LS139 that mounts on the backside of a MAD-1 decoder. Use it to connect multiple (max 4) PROMs to the MAD-1.

0.8mm thickness is preferred for easier soldering, but 1.6mm thickness is probably fine.

74LS139 is SO16 package. C1 is 0.1µF in 0603 package.

Address 1 & 2 pads = Use jumper wire to connect these to the next two highest address lines from whatever memory you are using. For example, if you are using 27C801 then use address lines A20 and A21 (connect A20 to pad 1 and A21 to pad 2).

The needed address lines might be present on the MAD-1 socket, in which case adding the jumper wires will be easy and clean. There are variation on how to wire these pins and I didn’t want to complicate the design with jumpers, so I opted to use solder pads with jumper wires instead.

Aside from the pads that attaches to the MAD-1 pins, there is no copper on the bottom side of the board, so you shouldn’t have to isolate it from the cart PCB. You may need to trim the legs of components (such as caps or resistors) on the PCB for a better fit.

ROM /OE 1, 2, 3 & 4 pads = Use jumper wire to connect these pads to the /OE pins on your PROMs. Pad 1 goes to PROM 1 /OE pin, pad 2 goes to PROM 2 /OE pin, and so on.

The 74LS139 is wired as follows:

Pin 1 - To MAD-1 pin 4

Pin 2 - Address line 1 (e.g. A20)

Pin 3 - Address line 2 (e.g. A21)

Pin 4 - PROM 1 /OE

Pin 5 - PROM 2 /OE

Pin 6 - PROM 3 /OE

Pin 7 - PROM 4 / OE

Pin 8 - GND

Pin 9~15 - NC

Pin 16 - +5v

You can also use this adapter for ExHiROM, you will just need to wire it a bit differently. For example, if you want to use two 27C322’s, then wire it in the following way: The pad for Address line 1, connect to A22. The pad for Address line 2, connect to ground. Then for the PROM /OE pads, connect pad 1 to the OE pin of your second PROM, and connect pad 2 to the OE pin of your first PROM. If it doesn’t work, then switch the /OE lines.

This is a SNES cart PCB that can be used for LoROM or HiROM games with a max ROM size of 16 Mb. It can be used for either a single game, or with the 74'161 installed it can be used as an X-in-1 multi cart. Games are switched by resetting the console.

I have tested this board with a 16 Mb HiROM game on a 29F160, as well as 2-in-1 LoROM games (2 x 4 Mb games) on a 29F800, and everything is working correctly. I will add instructions and a BOM when I get the chance. Until then, pretty much everything is self explanatory.

The jumpers for the four address lines (A20, A19, A18 and A17) control the X-in-1 multi game function. If you close pads 1 and 2 then that address line is controlled by the SNES. If you close pads 2 and 3 then that address is controlled by the 161. If you’re putting a single game on the cart, then close pads 1 and 2 for all four of them.

The placement of the TSOP will interfere with the cart shell support post. While it will fit as is, that post will be putting pressure on the TSOP which may eventually lead to damage. I recommend breaking that post off to avoid any possible issues. A new revision of this PCB is coming soon, and the TSOP will be moved so that it no longer interferes with the support post.

This board has been tested and found to work as expected.

There is a surface mount version available as well.

Description

You can use this PCB as a basic LoROM board with a max ROM size of 8Mib. Or, with the 74LS161 installed, you can use this board as a 2-in-1 or 4-in-1 multi cart. Games are switched by hitting the console reset button. This board was designed to use 27C080/27C801, but you can use other memory with a compatible pinout such as 27C040/27C401.

Jumper Settings

Jumpers JP1 and JP2 will have to be set depending on how many games will be on the cart and what size memory you are using. View the tables below to see how to set the jumpers when using 29C080 or 29C040 memory.

For example, “1-2” means to short pads 1 and 2.

JP1 controls ROM A19 and JP2 controls ROM A18. Other configurations can be made by using jumper wires.

Note on using 27C040 memory: 27C040 does not have an A19 address line, which is why JP1 is unused in this case. The highest address line on 27C040 is A18. If you close close the 2-3 pads on JP2 that will allow for a 2-in-1 (two 2Mib games), however, the games will be switched every other reset. If you want to use 27C040 and have the games switched on every reset, solder a bodge wire from JP1 pad 3 to JP2 pad 2. This will connect the highest address of 27C040 (A18) to the first output of the 161.

BOM

Notes

Use the SuperCIC key, found here. If your SNES is modified to deactivate the lockout chip, then you can omit this part if you wish. If you do not use the Super CIC, then omit C4 and R2. R2 is a pull-up resistor, the value isn’t crucial, anything 2.5 k (2k5) or higher should be fine.

If you are only installing one game on the cart, then you do not need the 74LS161 or C3. In this case, set both jumpers to the 1-2 position.

R1 value is determined by the LED that you use. Digi-Key has a calculator to make it easy. If you do not use an LED than omit R1.

JP3 controls the LED. If you bridge the left and middle pads, the PIC will control the LED. If you bridge the right and middle pads, the LED will have constant power. If you are not using using an LED then you can ignore JP3.

JP`1 and JP2 jumper pads are spaced for 0 ohm 0805 resistors, but you can simply use a blob of solder instead. Alternatively, you can use a bit of wire or the trimmed legs from C1.

DO NOT order this board with OSH Park’s standard 1.6mm board thickness. 1.6mm is too thick and you wont be able to insert the cart in the console (you will likely damage your cart slot if you somehow manage). You can get 0.8mm from OSH Park, and it should work fine, but please keep in mind that this is thinner than official SNES carts and may not always work properly. The correct board thickness for SNES carts should be 1.2mm, which sadly OSH Park does not currently offer.

Version History

Rev.B V2

• Added JP3 (select if LED is controlled by PIC or has constant power). • Added more ground plane area to front side. • Added silkscreen edge connector identifiers.

Rev.B

• Moved IC2 and C3 further from edge connector; amended related traces. • Improved various trace and via placements; reduced via count. • Moved location of C2; adjusted GND and +5V planes. • Fixed JP2 mislabeled silkscreen.