MMCE (SD2PSX / MemCard PRO2)

MMCE — Memory Card Mass Storage Emulation — lets OPL load PS2 games from an SD card inserted into a device (SD2PSX or MemCard PRO2) sitting in the PS2's memory-card slot. The protocol was created by bbsan2k; OPL's MMCE driver builds directly on that work. The device mounts as mmce0: or mmce1: and uses the same folder layout as USB.

Quick start

Folder layout

MMCE uses the same folder structure as USB and other folder-based devices. OPL creates any missing folders automatically on first launch.

The device prefix is mmce0:/ (slot 0) or mmce1:/ (slot 1). In conf_apps.cfg, reference ELFs on the MMCE card as mmce:APPS/MYAPP.ELF.

Where the MMCE settings live

MMCE Start Mode is in Settings → Game Sources, alongside the other device start modes. Everything else is on the MMCE Settings screen, opened from the MMCE Settings row just below it: MMCE Slot, IGR Bootcard Slot(s), Send GameID on Launch, Wait cycles after /ACK low, Use timeout alarms and MMCE Prefix Path.

MMCE Start Mode

Controls when OPL loads the MMCE driver and shows the MMCE Games tab.

Every device in Game Sources ships Off: a fresh install boots to the start menu with no tabs, and you enable exactly what your rig has. A saved config overrides the shipped default on load.

MMCE Slot

Selects which memory-card slot the MMCE device occupies.

MMCE Prefix Path

(On the MMCE Settings screen, opened from Game Sources.) An optional sub-path appended after the device root before OPL looks for game folders. Useful when your SD card serves multiple purposes and you want to keep OPL files in a subdirectory — for example, setting the prefix to OPL causes OPL to look for games in mmce0:/OPL/DVD/ instead of mmce0:/DVD/. Leave blank (the default) to use the root of the SD card.

IGR Bootcard Slot(s)

MMCE devices support In-Game Reset (IGR) — they can send a "switch to bootcard" command to the device on reset, allowing you to return to your boot exploit (e.g. FMCB) rather than the PS2 BIOS when you press the reset button inside a game.

The IGR Bootcard Slot(s) setting controls which slot receives the IGR command when the console resets.

Advanced MMCE Settings

These settings tune the low-level timing and locking behaviour of the MMCE driver. RiptOPL ships opinionated known-good defaults — Wait Cycles = 5 and Use Timeout Alarms = ON — which run cleanly on the vast majority of SD2PSX and MemCard PRO2 hardware. The aggressive 0-cycles + alarms-OFF pairing is the perf extreme the in-app hints warn about (a slow late-slim SD2PSX can lose the very first SIO2 handshake and freeze at the first read), so the fork even has a one-time migration that lifts an existing 0/0 config back to 5/ON. Adjust these only if you are experiencing instability or timeouts.

Wait Cycles after /ACK low

Extra wait cycles inserted after the MMCE /ACK line goes low, giving slower SD cards or cards with marginal signal quality more time to settle before the driver continues. Values: 0 through 5 (default 5). Lower values may improve performance but can cause instabilities; increase if you see read errors or hangs.

Use Timeout Alarms

When ON (the default), the driver uses hardware alarm interrupts to implement MMCE operation timeouts. When OFF, timeouts are handled without alarms — which may marginally improve performance, but removes the driver's only SIO2 timeout, so a genuine MMCE timeout can result in a hard freeze rather than a graceful error. Leave this ON (the shipped known-good default) so an occasional card hang converts into a recoverable timeout error rather than a freeze.

PS1 games on MMCE

MMCE supports PS1 games exactly like USB. Place *.VCD files and POPSTARTER.ELF in the POPS/ folder on the SD card. PS2/PS1 Game Display controls whether MMCE shows separate PS2 / PS1 views, a combined list, or one locked type; L3 is available only in Both (L3) and Mixed. See PS1 Games (VCD) for the full setup walkthrough and cover-art fallback chain.

MMCE is also a supported BDMA source for the exFAT POPSTARTER equip (BDMA Mode → MMCE (exFAT)), meaning POPSTARTER can read BDMA module files from the MMCE card when you use an exFAT-formatted SD.

Neutrino on MMCE

Per-game Neutrino is fully supported for games stored on MMCE. Copy the complete bundled neutrino/ folder to the MMCE game device, not just neutrino.elf. With a blank MMCE Prefix Path, use mmce0:/neutrino/ or mmce1:/neutrino/. If you use a prefix such as OPL, the resolver also probes that game prefix first — for example mmce0:/OPL/neutrino/ — before the bare mmceN: root.

The current Neutrino Device picker has three choices: Auto, Memory Card, and Game's Device. Auto is normally sufficient: it checks a custom path, then the active game's prefix and bare device root, then the APA HDD data home, and finally mc0:/mc1:. Game's Device is stricter: it searches only the active MMCE game device, with no custom-path or memory-card fallback, so a miss reports "not found" instead of silently using another copy.

Notes & tips

• MMCE and the built-in memory-card emulation on the same device share the memory-card slot. If your SD2PSX or MemCard PRO2 is also acting as a virtual memory card, OPL can still use it as a game source — the drivers co-exist.
• Game files should be defragmented. The easiest method: copy all files to PC, reformat the SD card, copy all files back. Up to 64 fragments per file are supported, but performance degrades with fragmentation.
• If games larger than 4 GB must fit on a FAT32-formatted card, use the USBExtreme split format (tools: OPLUtil, USBUtil).
• Cover art, per-game settings, VMC, and cheats work identically to USB — OPL looks in the same relative folders under the MMCE root (or the Prefix Path subdirectory if set).
• The config file (settings_riptopl.cfg) can be stored on the MMCE card. OPL probes MMCE before BDM devices during config discovery, so an MMCE-resident config is found reliably.
• MMCE is not MX4SIO. If your adapter uses the MX4SIO driver (rather than the bbsan2k MMCE protocol), it mounts as massN: via BDM — enable it with the USB/MX4SIO toggle in Game Sources, not the MMCE Start Mode. See USB / MX4SIO / iLink.