2 layers213 × 65.1 mm
2 layers100.1 × 67.3 mm
FC TxROM AX5202P
ponchick/FC-TxROM-AX5202P1Cartridge PCB with an MMC3 mapper built around the AX5202P IC.
- Size
- 100.1 × 67.3 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 29
- Nets
- 88
- Pads
- 274
- Tracks, vias
- 906, 41
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 3 May 2026
- Updated
- 3 Oct 2026
Overview
FC TxROM AX5202P is an open-source printed circuit board by ponchick, from the ponchick/FC-TxROM-AX5202P repository on GitHub, published under the CERN-OHL-P-2.0 licence. It is a 2-layer board of 100.1 × 67.3 mm with 29 parts on 88 nets, routed with 906 tracks and 41 vias.
It is built around the BAT85. Its parts include 6 capacitors, 4 resistors, 4 ICs, 2 diodes and 1 transistor. It belongs with the retro computing and games boards of this library.
Main components
1README
README.mdFC-TxROM-AX5202P
Cartridge PCB with an MMC3 mapper built around the AX5202P IC.
In theory, such a cartridge should support all TxROM-family board types. In practice, only the most common variants have been tested — no issues were found.
Russian version: README.ru.md
PRG RAM and battery support
The board supports PRG RAM for save data. A CR2032 cell retains data when the console is powered off.
- If a battery is installed (saves are required) — leave the NO BATTERY jumpers open (do not bridge them).
- If no battery is used (PRG RAM is on the board but saves are not needed) — bridge both NO BATTERY jumpers. PRG RAM is then powered from the console’s main supply, and data is lost when power is removed.
In no-battery mode, the following parts may be omitted:
- Battery BT1
- Resistors R1, R2, R3, R4
- Capacitors C4, C8
- Diodes D1, D2
- Transistor Q1
CHR ROM / CHR RAM selection
Some games need RAM instead of ROM for pattern tables. Selection is done with three jumpers on the board:
- CHR ROM mode — bridge the upper pair of pads.
- CHR RAM mode — bridge the lower pair of pads.
Mirror Control (mapper 118 support)
The two MIRROR CONTROL jumpers route CHR A17 and CIRAM A10. This is required for correct operation of different TxROM board subtypes.
- Upper position — for mapper 118 (TKSROM and TLSROM boards).
- Lower position — for standard TxROM (e.g. TKROM, TLROM) and most other MMC3 games.
If you do not use mapper 118, keep the jumpers in the lower position.
ROM type selection (pinout)
Two jumpers switch pins 1 and 31 of the ROM IC, because those pins differ between memory types.
- Upper position (
EEPROM/FLASH) — for electrically erasable ROM (EEPROM) and FLASH. - Lower position (
UV EPROM) — for UV-erasable EPROM.
Set the jumpers to match the ROM you install.
License
This project is licensed under CERN Open Hardware Licence Version 2 – Permissive (CERN-OHL-P-2.0).
See LICENSE for details.
SPDX-License-Identifier: CERN-OHL-P-2.0
Parts
29| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 0.1u | Capacitor_THT:C_Disc_D4.3mm_W1.9mm_P5.00mm | C1, C2, C3, C4 |
| 2 | 10u | Capacitor_THT:CP_Radial_D5.0mm_P2.50mm | C5, C8 |
| 2 | 1k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R1, R4 |
| 2 | BAT85 | Diode_THT:D_DO-35_SOD27_P7.62mm_Horizontal | D1, D2 |
| 2 | EPROM/FLASH | Cart:Jumper-3 | JP6, JP7 |
| 2 | TKSROM/TLSROM/OTHER | Cart:Jumper-3 | JP3, JP4 |
| 1 | +CE1 / A13 | Cart:Jumper-3 | JP1 |
| 1 | 100k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R2 |
| 1 | 2032 | Battery:BatteryHolder_Keystone_1060_1x2032 | BT1 |
| 1 | 27k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R3 |
| 1 | 2N3904 | Package_TO_SOT_THT:TO-92_Inline_Wide | Q1 |
| 1 | AX5202P | Package_DIP:DIP-40_W15.24mm | U3 |
| 1 | CHR ROM/RAM | Cart:DIP-32_Triple | U2 |
| 1 | FAMICOM_EDGE | Cart:CONN_EDGE_2x60 | J1 |
| 1 | LOGO | 0-Logo:ponchick | LOGO# |
| 1 | PRG RAM | Cart:DIP-28_Dual | U4 |
| 1 | PRG ROM | Package_DIP:DIP-32_W15.24mm_Socket | U1 |
| 1 | SRAM_VCC | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP9 |
| 1 | UNSAFE_CE | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP8 |
| 1 | VDD / A17 | Cart:Jumper-3 | JP5 |
| 1 | ~{WE} / A14 | Cart:Jumper-3 | JP2 |
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Questions
How big is the FC TxROM AX5202P PCB?
It measures 100.1 × 67.3 mm and has 2 copper layers, 1.6 mm thick.
What parts does the FC TxROM AX5202P use?
29 parts, built around the BAT85. 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 TxROM AX5202P KiCad files?
From the ponchick/FC-TxROM-AX5202P repository on GitHub, at the commit this page was made from: the board is FC-TxROM-AX5202P.kicad_pcb and its schematic FC-TxROM-AX5202P.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the FC TxROM AX5202P 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).