13 Aug
2013
13 Aug
'13
11:51 a.m.
On 8/13/13 1:26 PM, Andrew Lynch wrote:
Hi Ryan! Thanks! We need help with a dense, fast
DRAM/SDRAM/DDRx board in the worst way. Phat stacks of DDR RAM in the GBs and that
requires DDR encoder/decoder logic.
Neither John nor I know anything about it other than it is quite complex. I've used
the old school DRAMs (4164) but they are nothing in comparison to DDRx or whatever its
called.
Help! This is an urgent appeal. The S-100 80386 CPU board is basically boned without a
decent RAM board to go along with it. We have an 8MB SRAM board that works and can design
an 32MB SRAM board but that just gets you in the door.
Sophisticated Linux/BSD OS's all require GBs of RAM and 32MB won't even get a
boot screen. Maybe a dirty look from the barest of the bare bones Linux distributions.
Not much else.
Help! Thanks and have a nice day!
Andrew Lynch
Have you guys decided on the programmable logic yet (fpga)? One that
is happy with ddr is required, and fitting into 4 layers can be
difficult or impossible for bga if you want "big ram"- what are you
shooting for?
What I did on my 060 board was to put on two srams that were tqfp and 32
bit wide, 3.3v, hand solderable - some cypress part as I recall- you can
get a fair amount of ram that way to get something booted, no dynamic
bus sizing whackiness required (040/060) either and then debug your ddr
once you're up. Perhaps a ddr daughterboard? I could use something
like that as well- bring it out to a non-muxed addr and data bus, with
3.3v or 5v translators? I can never find a good (hand solderable,
small) connector for stuff like that- any ideas? I use DIN stuff, but
it is physically large = expensive pcb.
Also, I find netbsd to be the friendliest option- start with the vme port.
I'm afraid I know nothing about x86 memory, bus, etc. Let's take
this offline and chat.
-Ryan