Making PS1 Memcard for PS2

[pspgeek]

I am making a PS1 Memcard using a Teensy 2.0 and SD card. The memcard receives commands 52(read), 57(write) and 58(read that this command is for checking if a Pocketstation is inserted). The cmd 52 implementation is somewhat complete(shows all saves on Browser). I'm still working on cmd 57(in-game saving but no copying in Browser). For cmd 58 I haven't found anything other that it is 5 bytes long and that returning 0 at every byte appears as a Pocketstation.

So if anyone knows anything about these commands specially about cmd 58(the return values from Sony Memcard and Pocketstation) and if there is a time to read and write to SD card other than in between bytes received.

[Goku1992]

Why not just buy a ps1 memory card off of ebay for cheap? Why go through the trouble

[pspgeek]

I could buy a memcard but is actually something more like wanting to see if I can make it. Also would be easier to backup and restore. Also used almost all money for the ps2 so I'm doing something with what I have.

[SP193]

Have you taken a look at the sources of Jimmikaelkael's MCMAN module in the PS2SDK sources hosted at the PS2SDK Github? mcsio2.c seems to contain code related to the SIO2 commands that will be sent to the memory card via SIO2MAN.

[pspgeek]

thanks took a look and finally understood the cmd 58 but don't understand the second byte sent by memcard in 52 and 57. Something about it being 0,8(returns some kind of error) and other value(access denied). Is it related to the last write or something like that?

[SP193]

thanks took a look and finally understood the cmd 58 but don't understand the second byte sent by memcard in 52 and 57. Something about it being 0,8(returns some kind of error) and other value(access denied). Is it related to the last write or something like that?

Hmm... after doing a quick survey of McReadPS1PDACard() and McWritePS1PDACard(), a document on the Playstation and SIO.c from the PCSX emulator, I've reached this conclusion:

mcman_sio2inbufs_PS1PDA[0] - 0x81 (0x81 for Memory Card, 0x01 is for the gamepad)
mcman_sio2inbufs_PS1PDA[1] - SIO2 command (0x52 or 0x57, for READ or WRITE operations respectively).
mcman_sio2inbufs_PS1PDA[2] - (Returned) Unknown (0x5A).
mcman_sio2inbufs_PS1PDA[3] - (Returned) Unknown (0x5D).
mcman_sio2inbufs_PS1PDA[4] - Upper 8 bits of the page number (On return, 0x00).
mcman_sio2inbufs_PS1PDA[5] - Lower 8 bits of the page number.
mcman_sio2inbufs_PS1PDA[6] - (Returned) Unknown (0x5C). Seems to be returned by the Playstation's SIO.
mcman_sio2inbufs_PS1PDA[7] - (Returned) Unknown (0x5D). Seems to be returned by the Playstation's SIO.
mcman_sio2inbufs_PS1PDA[8+] - (Returned) Payload (Note: The real data seems to begin at offset 10 instead of 8. I believe that the leading 2 bytes are copies of bytes 4 and 5, sent back via the SIO from the MC, since the PCSX emulator suggests that).
mcman_sio2inbufs_PS1PDA[135] - (Returned) Unknown (0x5C). Seems to be returned by the Playstation's SIO. This byte is present for responses to the WRITE command.
mcman_sio2inbufs_PS1PDA[136] - (Returned) Unknown (0x5D). Seems to be returned by the Playstation's SIO. This byte is present for responses to the WRITE command.
mcman_sio2inbufs_PS1PDA[138] - (Returned) (Sony Memory Card) EDC data, only present when a READ command is used.
mcman_sio2inbufs_PS1PDA[139 for the READ command and 137 for the WRITE command] - (Returned) Unknown (0x47).... seems to be a terminator for the packet.

The "Unknown" values are the values expected by MCMAN. It is probably best to set those values in their expected locations, since they seem to indicate that the read/write operation was a success.

The 0x5C and 0x5D byte sequences seem to be the "OK" response code for Playstation memory cards, and the 0x47 byte seems to be a terminator for the end of the SIO packet.

It seems like an original Playstation SIO packet is encapsulated within a PS2 SIO2 packet.

So... the Playstation SIO stuff are sent over the SIO2 interface with encapsulation used... interesting.