Question
I am unable to correctly access/load to SDRAM on an older BF533 EZ-KIT Lite. Reading or writing SDRAM produces incorrect values or corrupted data, while loading code into SDRAM fails. Why is this?
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Answer
Due to high customer demand and the low cost of memory the SDRAM on the BF533 EZ-KIT changed between board revs 1.6 and 1.7. The ADSP-BF533 EZ-KIT with board revision 1.6 and older has 32MByte of SDRAM whereas board revision 1.7 and newer has 64MByte of SDRAM.
This change in size requires a change in the EBIU_SDBCTL register setting. For the older 32MB part it should be set to 0x13, while the 64MB SDRAM requires that the EBIU_SDBCTL is set to 0x25.
CrossCore Embedded Studio and VisualDSP++ 5.0 use default EBIU_SDBCTL values for the 64MB part. This means that customers using the older boards will experience issues accessing SDRAM if the EBIU configuration is not changed. VisualDSP++ 5.0 and CrossCore Embedded Studio support Custom Board Support Files. These are XML files which you associate with a particular Session within the IDDE, and allow you to define some register reset definitions to override those in the default file in "...\System\Archdef\". You can find more information about this approach in the Help system:
[VisualDSP++] VisualDSP++ Help under ‘Help’->’Contents’->’Graphical Environment’->’Custom Board Support’.
[CrossCore Embedded Studio] CCES Help under ‘Help’->’Contents’->’CrossCore Embedded Studio
1.0.x’->Integrated Debug Environment->Debugging Executable Files->Run/Debug Configurations Dialog Box->Custom Board Support Tab->Enabling Custom Board Support
Up to, and including, VisualDSP++ 4.5 the default EBIU_SDBCTL register value was for the 32MB part, and customers with revision 1.7 of the EZ- KIT who use the 'Use XML Reset Values' option must ensure that they have the correct SDRAM values set in ADSP-BF533-proc.xml. The settings for both revisions are contained in the xml file but the rev 1.6 settings are enabled by default. This file can be edited; however you should be aware that it is susceptible to being overwritten when an update is applied to your VisualDSP++ installation.
Attached are Custom Board Support files for both VisualDSP++ 5.0 and CrossCore Embedded Studio with the BF533 rev 1.6 and older (32MB) settings configured.
[VisualDSP++] In VisualDSP++ you can then associate the file with your session via 'Settings'->'Session'.
[CrossCore Embedded Studio] In CrossCore Embedded Studio you can associate the files with your session by going to the “Custom Board Support” tab for your Debug Configuration under ‘Run’->’Debug Configurations’.