Forum Post: DM8148 - Mcbsp Configuration

Hi,

I'm working with DM8148 EVM. I'd like to configure the Mcbsp from the dsp.

In previous posts, it was written that "DSP can not access McBSP directly (at physical address 0x47000000), but it should go through the system MMU, which translates the physical addresses to virtual addresses". Therefore, the mmu is related to the Mcbsp configuration.

My questions:

1.a. If I disable the MMU, by setting MMU_CNTL to 0, will the dsp access McBSP physical address directly?

   b. If all dsp accesses go through the mmu, how can I access the physical address of the MMU registers (such as for setting MMU_CNTL to 0)?

2. a. When I try to read SRGR2 physical address (in previous posts, there was a debate whether SRGR2 physical address is 0x47000100 or 0x47000000, so I read both addresses) I encounter a strage phenomenon - the value being read and the value being displayed in CCS memory window aren't the same. Which is the correct value? Does the values CCS display are after MMU translation?

     For example:

           tempPtr= 0x47000228;

           Val = *tempPtr;                     // This give the value of  0x6C6E50CD to Val. However, CCS memory window show that  address 0x47000228 contains value of 0.

   b. Why is the value being read of SRGR2 isn't 0x2000 (the value after reset)?

Thanks,

Gilad