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From: Jerry Van Baren <gerald.vanbaren@comcast.net>
To: u-boot@lists.denx.de
Subject: [U-Boot-Users] Where in u-boot is the RAM "Mode Register"	programmed?
Date: Thu, 22 Mar 2007 19:38:17 -0400	[thread overview]
Message-ID: <46031369.7000702@comcast.net> (raw)
In-Reply-To: <004b01c76ccc$e1bac370$6accdf0a@TQICORP.local>

Bjook wrote:
>  

[snip]

> The only problem is my hardware layout guy decided to mangle the address 
> lines when he connected the RAM to the ARM processor.  His reasoning was 
> that a RAM address is a RAM address is a RAM address.  If you always 
> access the RAM from the Arm chip then the mangled lines will always get 
> decoded and you will get the correct data value.
> 
> What the layout guy did not realize was that this RAM has a Mode 
> Register that needs to be programmed.  Where does this happen in 
> u-boot?  If I can find out where it is set then I can decode the mangled 
> address lines and put the proper value in.
> 
> Also I will set the ?burst read? to 0.
> 
> Do you think this situation salvageable?  A10 is the same because it is 
> a special line but I may need to jumper A8 and A9 since it looks like 
> they are only used to program the address register.

[snip]

> Next time I will fix the mangled lines but I really need to prove out my 
> design on my current 50 boards since another spin takes around a month 
> (because of BGA chips).
> 
> -Bjook

Oooooo, you get this working he owes you a lifetime supply of beer. 
Make him pay for a long time, don't drink it all at once. ;-)

grep is your friend and start.S is the place to start.
/u-boot/cpu/arm920t/at91rm9200/lowlevel_init.S

I'm not familiar with the ARM(r) memory controller.  If it just does 
address and data (looks like it), it should be salvageable (if so, it 
probably isn't worth re-laying out the board unless you have other 
problems).  The initialization is a stream of defines of (address / 
data) pairs at the labels SMRDATA and SMRDATA1.  You will have to warp 
the addresses, but it probably will work.

Good luck,
gvb

      parent reply	other threads:[~2007-03-22 23:38 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-22 21:56 [U-Boot-Users] Where in u-boot is the RAM "Mode Register" programmed? Bjook
2007-03-22 22:36 ` [U-Boot-Users] Where in u-boot is the RAM "Mode Register"programmed? Ulf Samuelsson
2007-03-22 23:38 ` Jerry Van Baren [this message]

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