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Posted: Fri May 22, 2015 6:14 pm
by Oerg866


Posted: Sat May 23, 2015 4:21 am
by darknezz19
Haha, new flash cart?

Posted: Sat May 23, 2015 5:47 am
by HardWareMan
darknezz19 wrote:Haha, new flash cart?
RAM based != Flash. It has more abilities.

But no DTACK, nor TIME. Pity.

PS Selling?

Posted: Sat May 23, 2015 8:24 pm
by Oerg866
HardWareMan wrote: PS Selling?
When it's done, yes :)

Posted: Tue Jun 02, 2015 8:20 pm
by doragasu
Looks extremely kickass!!!

Posted: Mon Jun 15, 2015 4:41 pm
by MrTamk1s
Ready? Go!


In all seriousness, please keep this a friendly competition, no :wink:?

Also, out of curiosity, what features will this RAM cart have? All I currently see is a giant PCB with no chips and no evidence if it even works. Pics/videos of operation or it never happened...

Re: Hmmmm.......?

Posted: Sun Jan 17, 2016 4:47 pm
by Oerg866
Yes, it does work (there are two working units right now).

But it's not ready for release just yet ;)

BTW: If you build one it has a BOM cost of under 25 EUR.

Imagine the rebates if I approach the fab with a large order :)

EDIT: @Hardwareman: I don't really need DTACK for anything, nor do I need TIME :)

Re: Hmmmm.......?

Posted: Wed Jan 27, 2016 8:13 pm
by prophet36
Oerg866 wrote:Yes, it does work (there are two working units right now).
Awesome, well done Oerg!

Re: Hmmmm.......?

Posted: Sat Jan 30, 2016 10:05 pm
by KanedaFr
25€ !!!
I can't wait for the specs !!!

Re: Hmmmm.......?

Posted: Sun Jan 31, 2016 7:59 am
by Oerg866

I've been a bit busy with school, so I'm just now finishing up the hard and softwarre side as far as the USB interface is concerned.

The specs right now are as follows:

* 6KB of internal firmware memory (it offers some diagnostic features such as mem test, ROM view, booting the Mega CD if you have one, etc.)
* 8 MB of SDRAM (100MHz CL2), the upper 1MB or so will be reserved once I get to implement debugging capabilities.
* USB 2.0 (Mini-B) interface (~4.5 MiB/s actual throughput)
* Fits in regular MD cartridge shell
* Quite a few debugging capabilities if you are developing the binary you are debugging (e.g. hardware ports to transfer arbitrary information to the host and whatnot) - of course you will have regular debugging functionality in any case :P

Here is the BOM as of october 2015:
11.68 Xilinx XC3S50AN Spartan 3AN FPGA
1.36 Alliance Memory, inc. AS4C4M16S-6TCN (4MBit * 16 SDRAM)
0.32 Diodes Incorporated AP2114H-3.3TRG1 3.3V 1A SOT223 regulator
0.32 Diodes Incorporated AP2114H-1.2TRG1 1.2V 1A SOT223 regulator
2.10 3x 74LVC(H)16245A 16-Bit Tri-State Bus Transceivers
3.79 FTDI FT232H 480mbps USB to UART/FIFO interface
0.20 Microchip Technology 93LC56BT-I/OT 2Kbit Config EEPROM for FT232H
1.12 passives (caps/res/etc)
1.53 100MHz Oscillator

= 22.42 EUR
Here are some videos of its current state:

(Excuse my voice and the lackluster presentation. It's 9AM and I haven't slept ...)


Re: Hmmmm.......?

Posted: Mon Feb 01, 2016 4:19 pm
by db-electronics
Very happy to see actual level converters on there...

Re: Hmmmm.......?

Posted: Wed Feb 03, 2016 2:07 am
by MrTamk1s
Nice to see it working in the videos, and FAST! Those specs are a beast. I believe in the cart now :wink:.
(And sorry for the somewhat rude post back in June. )

Re: Hmmmm.......?

Posted: Sat Feb 06, 2016 5:10 pm
by Oerg866
A few infidelities in the original board layout has made this necessary:

Switched from LDO to a switched reg for the 3.3, added /Time (For HardWareMan :D), added a failsafe jumper for FPGA core updates via USB (I just learned about multibooting FPGA bitstreams), brought down the BOM cost per unit even further and generally improved the routing of all busses immensely...

Maybe during the summer I am going to be looking for additional beta testers :)

Re: Hmmmm.......?

Posted: Mon Feb 08, 2016 1:39 pm
by db-electronics
Very good work! Auto-routers are for wimps! (And blokes who don't care for signal integrity)...

Re: Hmmmm.......?

Posted: Wed Feb 24, 2016 3:38 pm
by Oerg866

Time has come, my friends :) Time to beta-test the crap out of this.