I'm using a 6455 with external DDR2 memory. The 6455 gets loaded via the HPI (HPI16 mode) by a host processor.
Currently,
- the host processor loads the 6455 image into internal 6455 memory
- the 6455 starts running from internal memory and initializes the DDR2 Memory Controller Config Registers
- then external DDR2 memory is avaiable to use
Our application image size is getting large enough that we would like to be able to put some code in DDR2 memory rather than having to squeeze it all in internal 6455 memory.
I would like to have the host processor configure the 6455's DDR2 Memory Controller Config Registers before writing the 6455 image to the DSP.
I have tried this, but have not been successful. It seems the host can write to internal memory but
can not write to the DDR2 Memory Controller Config Registers (0x7800****).
In 645x HPI User Guide (SPRU969B) it says "Note that the HPI cannot access all DSP resources or peripherals;
see the device-specific data manual for a list of resources accessible through the HPI."
I have not been able to find any 6455 specific info that says they are not accessible?
My questions are...
- Should the host be able to write to the "DDR2 Memory Controller Config Registers" (prior to writing the 6455 image)?
- If so, any tricks or ideas on what I may be doing wrong?
thanks,
Brad