PCI burst transfer through DMA on MPC8349

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PCI burst transfer through DMA on MPC8349

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Contributor I

Hi,

We are working on the MPC8349EA PowerQUICC™ II Pro Integrated Host Processorbased system. We have configured the DMA block for direct mode, to transfer the data to PCI bus.

The maximum burst size that we are achieving now is only 32 bytes.

We need the following information on the DMA that we are using,-

  1. What is the maximum burst size that we can transfer using this DMA?
  2. What are the configurations that have to be done other than configuring the DMA mode register?
  3. What are configurations that need to be done in the DMA mode registers to send the burst of 1024[32 bit] data on the PCI [66 MHz] bus?

Please provide us the information on the configurations required to meet the point 3 of above mentioned query.

Thanks and Regards,

Santhosh.

 

 

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Specialist II
If you read the reference manual carefully, you will find that burst on the PCI bus are fixed size 8*32 bit (32 bytes) which corresponds to one DMA cache line.
If you want to transfer 1024*32 bit data you just write 32768 to the DMABCRn register and the DMA will split the transfer in 32 bytes chunks doing a burst for each chunk for you.
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