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how can we access sdram from atmel 8051

Started by gaus January 10, 2007
hello .........
can some buddy explain me the programming to access the sd ram throgh
8051
its very urgent........please tell me ...................or give the
solution in my email id g.gaurav.s@gmail.com

gaus wrote:
> hello ......... > can some buddy explain me the programming to access the sd ram throgh > 8051 > its very urgent........please tell me ...................or give the > solution in my email id g.gaurav.s@gmail.com >
As SDRAM is dynamic, and the bogstandard 8051 doesn't support dynamic RAM (I don't know if any variants do), you need extra hardware. Several controller designs are available on the web, like this: http://icculus.org/~jm/sdram/, but I don't know of any ready-made ones you can buy (because I haven't looked), so you'll also need a PLD of some sort to put it in. If it's an ordinary 8051 running at 5V, finding a suitable 5V PLD is a bit of a pig these days. Paul Burke
Paul Burke wrote:

> As SDRAM is dynamic, and the bogstandard 8051 doesn't support dynamic > RAM (I don't know if any variants do), you need extra hardware. Several > controller designs are available on the web, like this: > http://icculus.org/~jm/sdram/, but I don't know of any ready-made ones > you can buy (because I haven't looked), so you'll also need a PLD of > some sort to put it in. If it's an ordinary 8051 running at 5V, finding > a suitable 5V PLD is a bit of a pig these days.
Finding 5V SDRAM is probably even harder :) There were old designs around that did DRAM in SW, so with faster 80C51 variants, and faster SDRAM that could also be an option. Usually the bandwidths are low, bordering on the slowest the device can tolerate. For faster bandwidths, the CPLD will be needed. - something like an Atmel ATF1502BE/1504BE, or a Xilinx Coolrunner -jg