2 layers44.9 × 8.4 mm
Internal Controller Board
jeffqchen/Famicom-Expansion-Port-Switcher
Enable switching role of controller connected to the Famicom expansion port
16 parts29CC-BY-SA-4.0
2 layers44.1 × 11.9 mm
Twins Main PCB
jeffqchen/Famicom-Expansion-Port-Switcher29Enable switching role of controller connected to the Famicom expansion port
- Size
- 44.1 × 11.9 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 31
- Nets
- 16
- Pads
- 56
- Tracks, vias
- 136, 21
- Pours
- 184
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 2 Oct 2022
- Updated
- 5 Mar 2024
Overview
Twins Main PCB is an open-source printed circuit board by jeffqchen, from the jeffqchen/Famicom-Expansion-Port-Switcher repository on GitHub, published under the CC-BY-SA-4.0 licence. It is a 2-layer board of 44.1 × 11.9 mm with 31 parts on 16 nets, routed with 136 tracks and 21 vias.
It is built around the SN74AHCT1G08DBVR(AT). Its parts include 14 connectors, 8 resistors and 2 ICs.
Main components
1README
README.mdFamicom Expansion Port Switcher Mod
The expansion ports on the Japanese Famicom consoles have a problem - some western games are incompatible with the controllers connected to this port, due to the fact that this expansion port did not exist on the NES, and therefore was ignored by some devs.
Significant Titles Affected:
- Arkanoid II
- Battletoads
- Dragon's Lair
- Paperboy
- Pinball
- RoboCop 2/3
- Star Force
- Super Mario Bros. USA
- Snake Rattle'n'Roll
- Terminator 1/2
- Tetris (Tengen)
- Zelda II - The Adventure of Link
I created the FamiCoun and the TwinDiamond a few years ago and both suffered from this programming oversight by these devs. So it is only natural for me to take matters into my own hands to fix it.
This switcher mod will enable you to switch the role of the expansion controllers between internal and external. It requires experience in console modding and might not be friendly for everybody. Please keep this in your mind before attempting.
Details are provided in the Project Wiki, separated by console models and motherboard revisions.
Special Thanks
Voultar (for insisting on a proper logic circuit implementation)
Redherring32 (for providing the board scan of Famicom GPM for reference)
Zoggins (for spotting the problematic Twin Famicom motherboard rev)
Shield: 
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Parts
31| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 100K | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R5, R6, R7, R8 |
| 4 | 220 | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R1, R2, R3, R4 |
| 2 | MERGE | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP1, JP2 |
| 2 | REPLACE | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP3, JP4 |
| 2 | SN74AHCT1G08DBVR | DA15_Fix:SOT95P280X145-5N | U1, U2 |
| 1 | GND | DA15_Fix:Single Pad Pin | GND |
| 1 | LOGO | LOGO | G*** |
| 1 | P1D0 IN | DA15_Fix:Long Via | J1 |
| 1 | P1D0 OUT | DA15_Fix:Long Via | J5 |
| 1 | P1D1 IN | DA15_Fix:Long Via | J2 |
| 1 | P1D1 IN | DA15_Fix:Landing Pad | J9 |
| 1 | P1D1 OUT | DA15_Fix:Long Via | J6 |
| 1 | P1D1 TO GATE | DA15_Fix:Landing Pad | J10 |
| 1 | P1D1 TO SELF | DA15_Fix:Landing Pad | J11 |
| 1 | P2D0 IN | DA15_Fix:Short Via | J3 |
| 1 | P2D0 OUT | DA15_Fix:Short Via | J7 |
| 1 | P2D1 IN | DA15_Fix:Short Via | J4 |
| 1 | P2D1 IN | DA15_Fix:Landing Pad | J12 |
| 1 | P2D1 OUT | DA15_Fix:Short Via | J8 |
| 1 | P2D1 TO GATE | DA15_Fix:Landing Pad | J13 |
| 1 | P2D1 TO SELF | DA15_Fix:Landing Pad | J14 |
| 1 | VCC | DA15_Fix:Single Pad Pin | Vcc |
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Questions
How big is the Twins Main PCB PCB?
It measures 44.1 × 11.9 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Twins Main PCB use?
31 parts, built around the SN74AHCT1G08DBVR(AT). The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Twins Main PCB KiCad files?
From the jeffqchen/Famicom-Expansion-Port-Switcher repository on GitHub, at the commit this page was made from: the board is KiCAD/Twins/Twins Main PCB/Twins Main PCB.kicad_pcb and its schematic KiCAD/Famicom/GPM/DA-15 Board/DA-15 Board.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Twins Main PCB design in my own project?
Its repository publishes it under the CC-BY-SA-4.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).