2 layers99.1 × 69.9 mm
FC UNROM512-PRGRAM
ponchick/FC-UNROM512-PRGRAM
UNROM512 + PRG RAM Famicom cartridge PCB
35 parts3CERN-OHL-P-2.0
2 layers99.1 × 60.1 mm
FC UNROM512
ponchick/FC-UNROM5122UNROM512 Famicom cartridge PCB
- Size
- 99.1 × 60.1 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 25
- Nets
- 83
- Pads
- 232
- Tracks, vias
- 576, 51
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 1 May 2026
- Updated
- 1 May 2026
Overview
FC UNROM512 is an open-source printed circuit board by ponchick, from the ponchick/FC-UNROM512 repository on GitHub, published under the CERN-OHL-P-2.0 licence. It is a 2-layer board of 99.1 × 60.1 mm with 25 parts on 83 nets, routed with 576 tracks and 51 vias.
It is built around the 74HC32D, 74HC139D and 74HC377D. Its parts include 6 ICs, 5 capacitors and 1 connector. It belongs with the retro computing and games boards of this library.
Main components
3
74HC32D
SOP-14-40℃~+125℃ 1.5V~4.2V 1.9V、4.4V、5.9V 100mV、400mV、400mV 2 2V~6V 2uA 4 5.2mA 5.2mA 500mV~1.8V 6ns@6V,50pF 74HC Series OR Gate SOIC-14 Logic Gates ROHSNexperiaLogic Gates
74HC139D
SO-16-40℃~+125℃ 11ns@6.0V,50pF 160uA 2/4 2V~6V 74HC Decoder Single Supply SOIC-16 Signal Switches, Multiplexers, Decoders ROHSNexperiaSignal Switches / Encoders & Decoders / Multiplexers
74HC377D
SO-20-300mil-40℃~+125℃ 1 12ns 16ns@4.5V,50pF 2V~6V 3.5pF 3ns 4mA 4mA 74HC Series 77MHz 8 8uA D-Type Enable Rising Edge SOIC-20-300mil Flip Flops ROHSNexperiaFlip Flops
README
README.mdFC-UNROM512
UNROM512 Famicom cartridge PCB (UNROM/UOROM family, extended PRG-ROM bank switching).
Russian version: README.ru.md
More details about UNROM512 format and compatibility:
Jumpers (board configuration)
1) Flash memory mode (write protection / self-flashing)
| Configuration | FLASHLOCKED1-FLASHLOCKED4 | FLASHABLE | 74*139 | Bus conflicts |
|---|---|---|---|---|
| Not Flashable (write-protected) | Closed | Open | Not installed | Present |
| Flashable (self-flashable) | Open | Closed | Installed | Absent |
2) Mirroring
Mirroring must match the ROM you are programming. The game expects a specific mode (vertical/horizontal/1-screen). A wrong setting causes visual glitches.
Only one of these jumpers should be closed. For Vertical mirroring, close VERTICAL and keep HORIZONTAL and ONE open.
3) CHR RAM size configuration (8/16/32 KiB)
The actual CHR RAM size is defined by the physical RAM chip (for example, 62256 = 32 KiB). Jumpers only route the required address lines.
| Size | CHR RAM 8k | CHR RAM 8k/16k | CHR RAM 16k/32k | CHR RAM 32k |
|---|---|---|---|---|
| 8 KiB | Closed | Closed | Open | Open |
| 16 KiB | Open | Closed | Closed | Open |
| 32 KiB | Open | Open | Closed | Closed |
Use smaller CHR RAM sizes (8/16 KiB) only if the target ROM explicitly supports them. Most UNROM512 / Mapper 30 software expects 32 KiB. Forcing a smaller size on unsupported ROMs can cause errors.
License
This project is licensed under CERN Open Hardware Licence Version 2 - Permissive (CERN-OHL-P-2.0), see LICENSE.
SPDX-License-Identifier: CERN-OHL-P-2.0
Parts
25| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 0.1u | Capacitor_THT:C_Disc_D4.3mm_W1.9mm_P5.00mm | C1, C2, C3, C4, C5 |
| 2 | 74HC32 | Package_DIP:DIP-14_W7.62mm | U3, U5 |
| 1 | 62256 | Cart:DIP-28_Dual | U2 |
| 1 | 74HC139 | Package_DIP:DIP-16_W7.62mm | U6 |
| 1 | 74HC377 | Package_DIP:DIP-20_W7.62mm | U4 |
| 1 | CHR RAM 16k/32k | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP11 |
| 1 | CHR RAM 32k | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP12 |
| 1 | CHR RAM 8k | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP9 |
| 1 | CHR RAM 8k/16k | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP10 |
| 1 | FAMICOM_EDGE | Cart:CONN_EDGE_2x60 | J1 |
| 1 | FLASHABLE | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP5 |
| 1 | FLASHLOCKED1 | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP1 |
| 1 | FLASHLOCKED2 | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP2 |
| 1 | FLASHLOCKED3 | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP3 |
| 1 | FLASHLOCKED4 | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP4 |
| 1 | HORIZONTAL | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP8 |
| 1 | LOGO | 0-Logo:ponchick | LOGO# |
| 1 | ONE | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP6 |
| 1 | SST39SF040 | Package_DIP:DIP-32_W15.24mm_Socket | U1 |
| 1 | VERTICAL | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP7 |
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Questions
How big is the FC UNROM512 PCB?
It measures 99.1 × 60.1 mm and has 2 copper layers, 1.6 mm thick.
What parts does the FC UNROM512 use?
25 parts, built around the 74HC32D, 74HC139D and 74HC377D. 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 FC UNROM512 KiCad files?
From the ponchick/FC-UNROM512 repository on GitHub, at the commit this page was made from: the board is FC-UNROM512.kicad_pcb and its schematic FC-UNROM512.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the FC UNROM512 design in my own project?
Its repository publishes it under the CERN-OHL-P-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).