SpritesMind.Net

TmEE co.(TM) wrote:I've got 2Mbytes worth of SRAMs, but total of 20...30 chips...

Are you really need 10-16MB SRAM cart?

I really need at least 32Mbit cart... I will have to upgrade my flashcart to 64M soon.

TmEE co.(TM) wrote:I really need at least 32Mbit cart...

It's just eight 512K chips then, about $40.

TmEE co.(TM) wrote:...for a while I could locally buy 4Mbit SRAMs, but not anymore

I have this SRAMs.
But, for testing purpose is enough small amount of SRAM with external storage support (i.e. SD/MMC/CF). And for gaming it's true - too small memory and we need NOR FLASH.
If we divide constructively device at 4 parts: FLASH cartrige for gaming, SRAM cartrige for programming and testing, modified Mega Key for use FLASH/SRAM cartrige with boot device and boot device to expansion slot with support storage SD/MMC or CF. So, MD will be able to program FLASH cartrige independ of PC and then FLSAH cartrige can be used alone without boot device for gaming. All you need is copy favorite ROMs on SD/MMC or CF storage.
OK, I will start work on this project as soon as I get enough free time for this. Of course, you will get all docs about this project. And if you will help me with OS, it would be just great!

Hello,

I made the ECART.
It does work, and it is already able to flash the cartridge from a CF card without a PC. Also, read/write to any place of memory map using a PC and parallel port, like transfer suite does.
Also I have a special hacked BIOS ROM to run from cartridge port, and be able to flash the ECART in the case something goes wrong.

Hopefully, I'll build the final PCB this week.
I'd like to add more support, but that depends on free time and other things.

TmEE co.(TM) wrote:I really need at least 32Mbit cart... I will have to upgrade my flashcart to 64M soon.

Use (S)DRAM instead... they're cheap, fast and have a bunch of megabytes inside them, but they require a multiplexed address bus, cell-refreshing and RAS/CAS signal generation.

I think they are worth against 32 SRAMs of 256KB

Those things could be implemented in a CPLD with like 40 IOs.
___

Also for HardwareMan, does your hard-drive have a standard file-system? Like FAT?

Can you run programs from it? they have to be copied into a ram buffer (because HDdrives are slow), right?

Jorge Nuno wrote:Use (S)DRAM instead... they're cheap, fast and have a bunch of megabytes inside them, but they require a multiplexed address bus, cell-refreshing and RAS/CAS signal generation.

The 3 things are a problem for me, at least for now, unless I get more educated about these things...

patroclus wrote:Hello,

I made the ECART.
It does work, and it is already able to flash the cartridge from a CF card without a PC. Also, read/write to any place of memory map using a PC and parallel port, like transfer suite does.
Also I have a special hacked BIOS ROM to run from cartridge port, and be able to flash the ECART in the case something goes wrong.

Hopefully, I'll build the final PCB this week.
I'd like to add more support, but that depends on free time and other things.

hello patroclus,

welcome here , nice to see that you are still working on ecart

Jorge Nuno wrote:Also for HardwareMan, does your hard-drive have a standard file-system? Like FAT?

Yes. My code supported FAT16 and FAT32 file systems. With long file names.

Jorge Nuno wrote:Can you run programs from it? they have to be copied into a ram buffer (because HDdrives are slow), right?

Yeah, but not enough RAM for this. Basic internal RAM enough only for small tools.
So, here is draft of schematic diagramm for future device.

For now, I will not explain how it will works. Later, when assemble device on PCB and do some debug stuff I will answer on all your questions.

So, it is done! I can switch to software. If anyone want to help with it - welcome!

really nice

Is the cartslot taken from a Famicom clone ?

TmEE co.(TM) wrote:really nice
Is the cartslot taken from a Famicom clone ?

How you guessed?

very nice projects

I am curious about the read speed you have managed to get with the sd card as on a previous project (not megadrive related) of my own using a microcontroller driving the sd card I couldnt get a read speed faster than 0.5MByte/Sec

devzone wrote:very nice projects
I am curious about the read speed you have managed to get with the sd card as on a previous project (not megadrive related) of my own using a microcontroller driving the sd card I couldnt get a read speed faster than 0.5MByte/Sec

And where you hurry? The speed of 0.5 Mbytes/sec is normal. The cartridge size is 4 MBytes, so it will be copied only 8 seconds. While 4 MBytes FLASH programming can take up to a few minutes...

HardWareMan wrote:And where you hurry? The speed of 0.5 Mbytes/sec is normal. The cartridge size is 4 MBytes, so it will be copied only 8 seconds. While 4 MBytes FLASH programming can take up to a few minutes...

Thanks for the info, so my 0.5 wasnt as slow as I thought

Its a shame those flash devices are so slow to program, I may make a version of this dev board with added sram so that games/progs can be loaded quickly into the ram

Keep up the good work HardWareMan