DMA question. What is the differences between MLNO vs MLOFFNO vs MLOFFYES

[nijo]

Hey,

Could anyone help me with the difference between then these fields:

DMA_TCD0_NBYTES_MLNO
DMA_TCD0_NBYTES_MLOFFNO
DMA_TCD0_NBYTES_MLOFFYES

Any help greatly appreciated.

[konrada · Accepted solution]

They refer to the same memory address, so it doesn't matter which one you use. Depending on the DMA settings, the TCDx_NBYTES field has a different bit layout, and the different names are one way of coping with that. (My guess is that Freescale uses a generator to generate header files and documentation from a chip description, and the generator doesn't support a register with varying bit layouts).

[nijo]

Thank you very much for you answer.

Just for future reference this is what I found after you "tip", this is taken from MK60N512VMD100.h

union {
uint32_t NBYTES_MLNO;
uint32_t NBYTES_MLOFFNO;
uint32_t NBYTES_MLOFFYES;
};

(That is, they do indead reference the exact same memory address).