[U-Boot-Users] ECC DIMM's with walnut board

Thomas Schäfer tschaefer at giga-stream.de
Fri Apr 25 15:15:26 CEST 2003

Hi all,

I compiled u-boot 0.3.0 for the walnut board and run it, it was working fine. Then I replaced the shipped 32MB DIMM module with a 256MB DIMM module with ECC and the board hang:

U-Boot 0.3.0 (Apr 25 2003 - 12:10:17)

CPU:   IBM PowerPC 405GP Rev. E at 200 MHz (PLB=100, OPB=50, EBC=50 MHz)
           PCI sync clock at 33 MHz, internal PCI arbiter enabled
           16 kB I-Cache 8 kB D-Cache
Board: WALNUT405-EVB_22
I2C:   ready
DRAM:  256 MB

I examined the function spd_sdram in cpu/ppc4xx/spd_sdram.c and found that the ECC Correction Enable bits in the SDRAM0_ECCCFG register are set to 1 when ECC DIMM is detected. I removed this setting and the board was working without any problems.
The 405GP Reference board manual says that using an ECC DIMM on a walnut board, only half of the total DIMM size is available if it is enabled for ECC, but this seems not to work on my board.

Has anyone tried out to run the walnut board with ECC DIMM's? What DIMM's did you use? The DIMM I was trying is Infineon HYS72V32220GU (256MB, PC133-222-520).

Best regards

Thomas Schäfer


GIGA STREAM - UMTS Technologies GmbH

Konrad-Zuse-Str. 7
66115 Saarbrücken

Tel.: + 49 (0)681 / 95916 - 203
Fax:  + 49 (0)681 / 95916 - 100
E-mail: tschaefer at giga-stream.de

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