pico-SAM9G Micron vs Samsung DDR2 SDRAM memory initialization ?

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Tom Hartnett

Aug 31, 2013, 12:36:50 PM8/31/13
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I'm confused...

The pico-SAM9G45 schematic shows them using (Micron) MT47H64M8CF-3 DDR2 SDRAMs.. but the actual board is populated with (Samsung) K4T51083QG SDRAMs.

The Atmel AT91SAM9G45 ATLIB memories.c file shows support for the MICRON_MT47H64M and the SAMSUNG_M470T6554EZ3_CE6.

I'm sure the Samsung K4T51083QC is "close enough" to the Micron MT47H64M8CF for it to boot.. but I'm seeing some instability (fragile behavior) that makes me wonder if "close enough" is REALLY close enough.

Has anyone had a need to update/fix/modify/replace the Atmel AT91LIB memories.c file with something better (i.e. specific to the Atmel K4T51083QC)?


Tom Hartnett

Sep 17, 2013, 11:13:29 AM9/17/13
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I've been able to get the SDRAM initialized correctly.  (Once that was behind me, I was able to better diagnose and correct the "instabilities and fragile behavior" I was seeing.)

However, there are a few (I believe to be) problems with the board_memories.c source file (for both the Samsung and the Micron parts).  When they do an EMSR1 (Extended Mode Register Set 1) cycle, the "acknowledge" it by writing to BA1 = BA0 = 1 (it SHOULD be BA1 = 0, BA0 = 1).  These problems are in "step 18" of the Micron/Samsung initialization and "step 8" of the Samsung initialization.

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