Devcart wishlist?

[KanedaFr]

I also made some (quick) research about Ethernet.
I quickly drop Wifi because of the cost (everything higher than 50$ is no longer a homebrew project...for me)
Yes, the Wiznet solution is the best I alos found (price and possibility)
But I don't think it's suitable for a dev cart...
How do you handle IO ? apart to embed a webserver on the devcart, I don't see how to do this...and I think it'll ask more time and knowledge than with a USB dev cart
Perhaps I'm wrong, but I think a USB dev cart let you add almost any feature you want to the Genny or to the PC side....while a LAN one not.

on a side note, a USB dev cart with an SPI port and a processor would make it possible to add Ethernet support, no ?

fyi, I made my first research on Ethernet because I was looking for a way to load games from my NAS to my Genny

[HardWareMan]

Agreed. Given that all the dirty work on the network does by chip from WizNet (hardware acceleration), and provides easy channel for sending and receiving raw data (sockets, up to 8 bidirectional in one chip!), then the target device virtually nothing is required only customers targets. Flawless profit!
From the device side: setup network bridge (IP, sockets), then do just "open", "write / read", "close" with desired socket. From the computer side: the program works with sockets (the same thing: "open", "write / read", "close"). You can use 2 sockets: one for commands and one for data, like FTP for example. Commands can be made like a console style such as telnet.

[KanedaFr]

socket!!! of course...I totally forgot it!
I only see a problem : IP configuration.

An usb device, you plug in it and your soft is able to find it quite easily
A ethernet device, you have config your soft with the device IP and, of course, your device musn't be IP locked...and so you must be able to define it or automatically assing it but how retrieve it ? on our case, you have it to print it on TV Screen...

[Charles MacDonald]

I gave up on USB. Now I use the LAN. See for yourself. I bought the unit for $12.

I'm getting conflicting information about this one; can the Wiznet module really be run at 5V and interface with 5V I/O? Or will I need a lot of level shifters?

I'm really glad to hear you used this solution and had no troubles. I'll seriously consider it now.

Kaneda, I agree about the IP configuration problem. The USB interface is simple enough (and the module is quite small) that maybe I could try including both. But then there will be this modem conflict issue you have...

[Chilly Willy]

If you look at the WIZ830MJ, it says in the Datasheet that it runs on 3.3V and is 5V I/O tolerant. It also uses a 16 bit data bus, so it looks ideal for a dev cart. Just include headers on the dev cart and the user can buy and plug in the WIZ830MJ themselves.

As for the IP address, I'd default the firmware on the dev cart to use something like 192.168.1.110, then allow the user to change that via whatever menu the dev cart uses. Most routers default the addresses to the local net to be 192.168.1.100 and up. You'd have to have more than ten local addresses before 110 would collide with another device.

[KanedaFr]

Kaneda, I agree about the IP configuration problem. The USB interface is simple enough (and the module is quite small) that maybe I could try including both. But then there will be this modem conflict issue you have...

I had this problem...but it seems it's only me....plus I didn't use this modem anymore

so go ahead, make it like you wanted to !

[Charles MacDonald]

If you look at the WIZ830MJ, it says in the Datasheet that it runs on 3.3V and is 5V I/O tolerant. It also uses a 16 bit data bus, so it looks ideal for a dev cart. Just include headers on the dev cart and the user can buy and plug in the WIZ830MJ themselves.

Oh I see, there are different versions of the breakout board using the same chip, and some people put a 3.3V LDO regulator on the board itself. Given the high availability it is probably best to support the SparkFun board in particular. I agree about the headers; that way nobody has to solder a 100-pin LQFP chip and can just stick the module in, or skip it and go with USB. (or vice-versa)

[HardWareMan]

Yes, WizNET's chips does not support DHCP (or not yet). But, there are simple solution: use some predefined IP from group C. For example, 192.168.1.1, like it does SOHO routers. Or, use some custom IP from your own network range. And it must be hardcoded to "factory" settings, to be able return device control without any additional tools. Of course, there must be "user defined" settings of IP and Sockets. Of course, this is superfluous if we have screen and joystick (yes, user can input any desired IPs directly). I see no problem, and you?

[Jorge Nuno]

I wish I saw this thread earlier to take some ideas into my cartridge :


(sorry for the huge pic)
Firmwares still very incomplete , but the features are:

- Up to 16MB (maybe 32) of D-RAM (Minimum bank size = 256kbytes);
- USB;
- MicroSD slot;
- 512kB of MRAM (3 save banks + 68k bootloader);
- I2C eeprom allowing some eeprom games to save;
- Updateable firmwares from USB;
- Battery for keeping games' binaries in RAM (so they don't have to get loaded from USB or card every power-on).
- Expensive to make as f*ck (not planning to sell it so I don't really care)

(I2C memory and battery not installed yet)

[HardWareMan]

Masyanya already done some very cool stuff:

128MXSPI (portable card device)
1. Up to 16 MBytes FLASH (as 256 pages by 64KBytes), do not required PC connection anymore.
2. 2 SPI's on board: 2 SD/SDHC/MMC/MMCMobile card supported (one internal and one external).
3. 32KBytes of SaveRAM as 4 pages by 8KBytes (up to 4 games with 8KBytes save size simultaneously).
4. Supports 6 mappers, EEPROM save supported (can save at NBA JAM for example).
5. Support FAT12/FAT16/FAT32, wich gives with SDHC hold whole ROM set in internal slot. :3
6. Internal FLASH can be divide to few ready to run games/progs.
7. SEGA MASTER SYSTEM games support (with standard mapper SEGA 315-5365).
8. Support updating OS, bootloader and CPLD.
9. Support LFN, ROM infos and more other cool stuff.
10. Has detailed docs for users and programmers.

From $40 (min) to $80 (max), depends on equipment.
Some pics:



Demo video
Already have it. But, it still NOT RAM. I want same thing but with RAM (DRAM/SDRAM not matter, 32MBytes or more with page-based structure).

[Charles MacDonald]

I wish I saw this thread earlier to take some ideas into my cartridge :

Totally awesome stuff, and way beyond my skill level. I can't compete.

Sometime, I wouldn't mind learning how you were able to make the DRAM refresh work while running the ROM at full speed without DTACK delays. It seems impossible to do!

- Expensive to make as f*ck (not planning to sell it so I don't really care)

What parts were expensive? It looks very compact/efficient to me, though maybe there are some more things on the back of the board?

I'm still working on mine, hopefully before the New Year I'll have something to show off.

HardWareMan, that flash cartridge looks incredible. Is there a webpage with more information about it?

[HardWareMan]

Sometime, I wouldn't mind learning how you were able to make the DRAM refresh work while running the ROM at full speed without DTACK delays. It seems impossible to do!

Hidden refresh cycles. I'd already done this in my project. SIMM72 speed enough for M68K @7,6MHz with zero wait states (and Read-Modify-Write supported!). There is an interesting document. It can do some explains how to connect DRAM to M68K.

HardWareMan, that flash cartridge looks incredible. Is there a webpage with more information about it?

Only in russian, sorry.

[Graz]

I'm pretty interested in hardware development and I have a bunch of ideas of things I want to do with FPGAs connected to the MD. However, I don't want to go to the trouble and expense of building a full featured flash/RAM cart like the ones in this thread. For me, my ideal devcart would have a passthrough edge connector on top. That way I could make a simple cart with an FPGA and not much else and plug it in the top, using the devcart to test software and such.

I realize I could put an FPGA on board with a passthrough connector on the top - I'm just saying what I'd want from the ultimate devcart. Something that still lets me screw with the 68k bus.