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SDRAM init & data bus

Started by aleksa February 22, 2011
I need someone to confirm that the SDRAM
does not use data bus to receive commands.

Which means that I can mix the data bus in whatever
way it suits me while am routing the PCB... right?

(i.e., connect D0 on MCU do say, D5 on SDRAM)

TIA


P.S.
I really don't like the guy who wrote 0xcafedede
in SDRAM init on Atmel's examples.


On 02/22/2011 10:51 PM, aleksa wrote:
> I need someone to confirm that the SDRAM > does not use data bus to receive commands. > > Which means that I can mix the data bus in whatever > way it suits me while am routing the PCB... right? > > (i.e., connect D0 on MCU do say, D5 on SDRAM)
Correct. Only address bits are used for configuration. If you need >8 bit wide SDRAM, and you want single byte writes, you have to be careful to keep D0-D7 in the same group, as well as D8-15, etc...
On 02/22/2011 01:51 PM, aleksa wrote:
> P.S. > I really don't like the guy who wrote 0xcafedede > in SDRAM init on Atmel's examples.
What, you wanted it to be 0xdeadbeef? -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
Tim Wescott wrote:
> On 02/22/2011 01:51 PM, aleksa wrote: >> P.S. >> I really don't like the guy who wrote 0xcafedede >> in SDRAM init on Atmel's examples. > > What, you wanted it to be 0xdeadbeef? >
Or the Java crowd 0xcafebabe
On 02/22/2011 03:23 PM, Dennis wrote:
> Tim Wescott wrote: >> On 02/22/2011 01:51 PM, aleksa wrote: >>> P.S. >>> I really don't like the guy who wrote 0xcafedede >>> in SDRAM init on Atmel's examples. >> >> What, you wanted it to be 0xdeadbeef? >> > Or the Java crowd 0xcafebabe
I once had a phrase generator for this sort of situation -- you gave it a character set (a b c d e in this case, or a b c d e O I S, if you wanted to interpret numbers as letters), and a number of characters to use, and it would choose all the phrases that would fit into that number of characters, using that character set. It still wouldn't be able to generate "0xfab4bdead", which a colleague of mine used for IEEE-1394, which has a 36-bit field (address, I think) in it someplace. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html