Hi All,
I am currently trying to perform DMA transfers between 5509A and an SD
Card connected via McBSP1, which is configured in MMC/SD Mode.
I set-up my DMA source as a buffer in DARAM (auto post inc) and my
destination as MMCDXR, and use MMC/SD1 Transmit Event (XMMCEVT1) as
the Sync event via the DMA Channels CCR register.
For whatever reason, my DMA transfer does not trigger automatically
even although XMMCEVT1 appears to be present i.e. DXRDY flag is
present in MMCST0 status register.
The only way I can get it to trigger is to enable my DMA Channel and
then perform a manual write to MMCDXR, which in turn triggers the DMA
transfer.
However, I do not want to rely on this, as its not very pretty. I
suspect that the DMA channel is not recognising the original XMMCEVT1
Sync event as it may have occurred before the DMA was configured, and
that by performing a manual write, the DMA channel is picking up the
fresh event.
Is anyone aware of a nice way to handle this, or am I perhaps missing
something.
I can perform DMA reads successfully using RMMCEVT1, without having to
perform any manual read.
Any light you can shed on this matter would be greatly appreciated.
Cheers,
Scotty
