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SNES LoROM Multi Cart (THT - Rev.B)

NOTE: This board is untested. It is the same as the surface mount version and should work fine, but has not been tested yet.

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.

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 do not populate C4 or R2. R2 is a pull-up resistor, the value isn’t crucial.

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, you can leave R1 unpopulated.

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. Proper board thickness for SNES carts should be 1.2mm, which OSH Park does not currently offer.

UNTESTED I will update this once I get my boards in and have a chance to test them.

http://dcemulation.org/?title=Dreamcast_480p_XRGB-mini_Framemeister_Cable

All the info you need is in the above link. Only additions are C6 decoupling capacitor (0.1µF) and JP1 (wire to SPST switch to select between 240p/480i and 480p modes).

Stereo to Mono Audio Adapter

http://www.rane.com/note109.html

See Figure 2 from the above link. This takes a stereo audio signal and sums it to a mono output. Read the above linked page for more info.

TRS = Tip, Ring, Sleeve. T is the LEFT channel and R is the RIGHT channel (although it really doesn’t matter since you’re summing them). S is GROUND. All resistors are 0805 size. Use either mono output, they are both the same (or use both for a dual mono output).

R1/R2: 475 ohm, 1% tolerance R3: 20 k ohm, 1% tolerance

Use shielded cable for inputs/outputs for best results.

SEGA Genesis Multi Cart

NOTE: This board is currently untested. I will update this once I get my boards in and have a chance to test them.

Thanks to HD Retrovision for sharing their Genesis cart (you can find it on OSH Park here ). I cheated and used the board outline instead of starting from scratch. : )

This can be used as a basic Genesis cart with a max ROM size of 8Mib. Or with the 74161 installed, you can use this as a 2-in-1 or 4-in-1 multi cart (combined ROMs can be a max of 8Mib). Games are switched by console reset button.

There are jumpers for the A18 and A17 address lines that will have to be set depending on how many games will be on the cart and what size memory you are using. For either jumper, closing positions 1 and 2 will allow the console to control that address line. Closing positions 2 and 3 will allow the 161 to control that address line. View the tables below to see how to set the jumpers when using 29F800 or 29F400 memory.

Memory = 29F800

Memory = 29F400

More options are possible, but will require jumper wires and/or cutting traces. There are solder pads for +5V, GND, A18, A17, A16, the reset line, and all four outputs of the 161. There are too many possibilities to list them all, but to name a few… You can make an 8-in-1 cart consisting of eight 1Mib games on a 29F800, or a 4-in-1 using a 29F400, you can wire in a mechanical switch to select games instead of using the reset line, you can wire in LEDs to indicate which game is currently selected.

BOM:

*If you are only installing one game on the cart, leave U2 and C3 unpopulated.

**R1 value is determined by the LED that you use. If you use another LED than the one listed above, then you may have to change the value of R1. Digi-Key has a calculator to make it easy. If you do not use an LED, you can leave R1 unpopulated.

***Jumper pads are spaced for 0 ohm 0805 resistors, but they are not necessary. You can simply use a blob or solder, or a bit of wire, or the trimmed legs from C1.

LED is 1206 package to make it easy if you wish to use a through hole LED instead of surface mount (it has the benefit of standing tall in the cart shell).

New version here: https://oshpark.com/projects/4dRNWL26

You can use this PCB as a basic LoROM board with a max ROM size of 8Mib. Or, with the 74'161 installed, you can use this board as a 2-in-1 or 4-in-1 multi cart. Games are switched by console reset.