Kinetis Microcontrollers中的主题 Re: DMA question. What is the differences between MLNO vs MLOFFNO vs MLOFFYES

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

nijo — Wed, 23 Nov 2011 17:37:38 GMT

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.

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

konrada — Tue, 29 Nov 2011 23:16:34 GMT

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).

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

nijo — Fri, 02 Dec 2011 23:01:44 GMT

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).