Forums

Problem with McBSP XWDLEN

Started by Unknown April 2, 2007
   I'm developing on DSK with C6713. A want send data by EDMA at 100MHz 
to McBSP0. I configured EDMA and McBSP by DSP/BIOS Configurator.

   But, there is a problem. When I set Element length XWDLEN to 16-bits, 
everithing is OK, but, when I set Element length to 8-bits, output data 
are inconsistent.

   Example, when I sending 0xAA (10101010) at loop...

16-bits - OK - 101010101010101010101010101010101010101010101010101...
  8-bits - ?? - 10101010????????10101010????????10101010????????101...

??? - it's something as hi impedance.

Where is mistake? Is it possible sending 100MHz data with CPU at 200MHz?

Thank for reply.

-- MiLo
Miloslav H�la wrote:
> I'm developing on DSK with C6713. A want send data by EDMA at 100MHz > to McBSP0. I configured EDMA and McBSP by DSP/BIOS Configurator. > > But, there is a problem. When I set Element length XWDLEN to 16-bits, > everithing is OK, but, when I set Element length to 8-bits, output data > are inconsistent. > > Example, when I sending 0xAA (10101010) at loop... > > 16-bits - OK - 101010101010101010101010101010101010101010101010101... > 8-bits - ?? - 10101010????????10101010????????10101010????????101... > > ??? - it's something as hi impedance. > > Where is mistake? Is it possible sending 100MHz data with CPU at 200MHz? > > Thank for reply. > > -- MiLo
Look at the data sheet. It says the maximum speed is CPU/2 or 75 MHz, whichever is smaller.