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map430f5438a: Can I set up again the size of DMAxSZ?

asher bara
Intellectual 900 points

Hello,

i'm using the mspf5438A.

What is the procedure in relation to resize the DMAxSZ?
 
I found no reference to the how to  change DMAXSZ during work.

Is it possible?
For example,if I'm supposed to transmit information
of various lengths and receive various length of information.
Can I set up  the size of DMAXSZ  again?

Asher.

  • 0
    Guru 322020 points

    What exactly do you mean with "during work"?

    You must not change DMAxSZ while a DMA transfer is running (if the description in the User's Guide is correct, it will be reloaded with the original value once it reaches zero). But when the DMA is no longer active, there is no problem changing it in preparation for the next transfer.

  • 0 in reply to Clemens Ladisch
    Intellectual 900 points
    Hello,

    i mean in "During work" , when the DMA was set once and transfer data
    and now need to set the DMA again to new size, destination, source address.

    So,
    1) one way is to wait that the DMA will stop ( wait to DMAEN == 0)
    2) second way, in case of repeated burst ( DMAEN is always set)
    , need of force DMAEN = 0.

    and just after that can set the: DMAxSZ.

    i believe that the same priciple is for changing
    DMADA, DMASA. (I have not found anything that contradicts it).

    I will check it in my code.

    Thanks.
    Asher.

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