When I create a BSB project for the PowerPC 405 with the PLB at 200 MHz and OCM at 100 MHz, the OCM does not work properly.
The C_ISCNTLVALUE and C_DSCNTLVALUE parameters are not set up properly in the BSB project. They are set as 0xa1. They should be set to 0xa3 when the clock ratio is 2:1.
For a detailed explanation of the ISCNTL and DSCNTL register bits, refer to "PowerPC 405 Processor Block Reference Guide" -> PowerPC 405 OCM Controller -> Programmer's Model.