MCGenjin MultiMapper

[TailChao]

Hi, I've started working with the PCE and made a multiregion memory mapper.


You get up to 8MB of banked ROM and can switch the order of the datalines whenever you like. Two chipselects are also given for whatever use your imagination can come up with. Everything fits in a single EPM7032LC44 CPLD, but the VHDL source is given for anyone wanting to use a different CPLD or add features.

Documentation, source, POFs, etc. is all available here:
http://www.penguinet.net/TailChao/Hardw ... /index.php
Enjoy.

[MooZ]

Excellent! Is there any production planed?

[TailChao]

Excellent! Is there any production planed?

I have parts for five boards like the one shown on the webpage.
They’re configured with one MCGenjin, FM1608 (8KB FRAM), and a socket for one DIP expanded 29F032 (4MB FlashROM). The second MCGenjin chipselect line is free to connect whatever is in your imagination. But these boards are really simple and messy, and were really meant just to test MCGenjin. Two of them I need to keep for myself, but the rest can be lent out if someone really wants one.

I’m slowly working on a small board which can fit inside a plastic shell and end up looking like a CD System Card that had too much for lunch. But something like this is really meant only for mass production of new software, you cannot reprogram the FlashROM from the cartslot.

I have no plans for a big PCE project right now, I just wanted to learn the hardware and solve the annoying region problem. So I do not think I can do a huge production run of development boards right now. But I can offer the following:
-I can assemble and lend out one of the three extra devcarts I have. But this requires that the owner has a 29F032 with a DIP adaptor and programmer that supports it. They’re also really ugly.
-If you want to build your own board using MCGenjin, but have no CPLD programmer, I can send out programmed MCGenjins for the cost of shipping (these CPLDs were gotten from a pile of waste).
-If there is some interest, I can do board layout for MCGenjin devcarts that have a FlashROM socket and include some FRAM and SRAM attached to the chipselects, then put the gerber files up after I make sure everything works. Same size as a HuCard, but no nice plastic shell. I use 29F032 expanded to DIP for everything, but if people like other chips I could do a few layouts. If there is demand for 8-10+ boards, I could get things manufactured. So something like the Lynx carts I made:

[MooZ]

-If there is some interest, I can do board layout for MCGenjin devcarts that have a FlashROM socket and include some FRAM and SRAM attached to the chipselects, then put the gerber files up after I make sure everything works. Same size as a HuCard, but no nice plastic shell. I use 29F032 expanded to DIP for everything, but if people like other chips I could do a few layouts.

That would be awesome!

[TailChao]

-If there is some interest, I can do board layout for MCGenjin devcarts that have a FlashROM socket and include some FRAM and SRAM attached to the chipselects, then put the gerber files up after I make sure everything works. Same size as a HuCard, but no nice plastic shell. I use 29F032 expanded to DIP for everything, but if people like other chips I could do a few layouts.

That would be awesome!

Ok,


MCGenjin, 29F032 in DIP, 128KB SRAM, and 8KB FRAM. It will take me some time to do the layout and testing, but I'll put up the final gerber files for everyone when things are finished.

Also, if anyone else wants one of the older testcarts two are left.

[TailChao]

Hi all,

I have just finished testing the 4MB MCGenjin boards, and have uploaded the gerber files and new POF.
The layout is like this:


More pictures and files are available here: http://www.penguinet.net/TailChao/Hardw ... /index.php

I hope this helps with some of your projects. Enjoy!

[MooZ]

I want one!
By the way, how do you upload rom or backup the fram?

[TailChao]

I want one!
By the way, how do you upload rom or backup the fram?

If you want a pre-made card, please PM me. But it is not so bad to build it on your own.

The ROM must be copied to flash using a chip programmer (which is why the 29F032 is socketed). MCGenjin traps all writes to ROM in order to update its internal registers, and adding writethrough support would require a larger CPLD.
Unfortunately, chip programmers which support the 29F032 are usually expensive. But, it's quite easy to make a converter from the 29F032 socket in this card to a much more common EPROM such as the 27C801. You would only get 1MB of storage in that case, but could keep the FRAM, SRAM and multiregion features. Keep in mind that the 29F032 socket on the board really is just a 1-1 DIP expansion of the TSOP chip. So there's lots that can be done from there, and it's why I like to use this form factor for SNES, etc.

As for the FRAM-
If you mean keeping the game saves after the power is turned off, there is nothing to do. You just write to it like normal SRAM, and the data is retained without the need for a battery. But keep in mind that if your game is saved in one region, and you decide to play in another one, all of the data will be backwards! So you need to keep a flag tracking the last region used.

If you mean backing up the data on FRAM to something like a PC, it could probably be done by using some of the output pins on the controller port as software serial. But I have not put much thought into this.

[MooZ]

I've never soldered a PLCC chip. Is it hard? The smallest package I soldered was the SOIC version of the Atmel 16Mb dataflash.
I think I could build a simple EEPROM burner using an AVR based board (like this Game boy flasher). I have this board which seems to have enough pin for the 29F032.

If you mean backing up the data on FRAM to something like a PC, it could probably be done by using some of the output pins on the controller port as software serial. But I have not put much thought into this.

Exactly. Having a serial port will be cool. This way the board used to burn eeprom will be able to backup the FRAM to a PC.

[TailChao]

I've never soldered a PLCC chip. Is it hard? The smallest package I soldered was the SOIC version of the Atmel 16Mb dataflash.

PLCC is not so bad. It's a little more annoying than say TSOP or SOIC because the pins run up the side. The approach I always used was to tin the legs and contacts, then solder two pins on opposite sides of the chip. You can then flip the board on its side, so it's easier to do the rest of the chip legs. But I'm sure there's a better way.

I think I could build a simple EEPROM burner using an AVR based board (like this Game boy flasher). I have this board which seems to have enough pin for the 29F032.

That could work. Plus if there's not enough pins you could just attach an external counter or something.

If you mean backing up the data on FRAM to something like a PC, it could probably be done by using some of the output pins on the controller port as software serial. But I have not put much thought into this.

Exactly. Having a serial port will be cool. This way the board used to burn eeprom will be able to backup the FRAM to a PC.

Huh, this is not too bad of an idea.
I think it would be more beneficial to put it on the console-side though. So the game software could use the PCE controller port as software serial and send the FRAM data to the PC. Or play tones on the PSG which can be recorded and decoded later.

Also-
Since there are so many possible card configurations for this mapper, I've put together a draft standard for game headers, etc here: http://www.penguinet.net/TailChao/Hardw ... jin_SP.txt
So if emulator support is added, it will be easy to determine what the game software is expecting.