msp430f2618 DMA address assignment

Krishn_JI

Other Parts Discussed in Thread: MSP430F2618

I am using MSP430F2618 Microcontroller and doing programming in Code composer studio v6.

I have seen below two instructions for DMA operation but i don't know meaning of those...

Please explain below two instructions...

DMA0SA = (void(*)())sample; // Source block address
DMA0DA = (void(*)())&DAC12_0DAT;

here sample is the name of array which i defined to store the data of integer type.

over 10 years ago

0 Clemens Ladisch over 10 years ago

Guru 325170 points

The SA/DA registers have 20 bits to be able to access the entire address space.

"(void(*)())" casts the value to a function pointer. This ensures that the DMA registers are written with 20-bit values even if the compiler is configured to use 16-bit data pointers.
(A better way would be to use the __data16_write_addr() function.)

0 Krishn_JI over 10 years ago in reply to Clemens Ladisch

Expert 2145 points

Hi,

i use following array to store the data

sample [] ={1,2,3....}

now as per array property 'sample' variable contains the address of first element of array.

so can i write DMA0SA = sample; ?

what is __data16_write_addr() function ? please explain it in detail

0 Clemens Ladisch over 10 years ago in reply to Krishn_JI

Guru 325170 points

When your array is in the lower 64 KB address space, or when data pointers use 20 bits, you can assign the address directly.

See the application report SLAA376: Extended Memory Access Using IAR and CCE for details.

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msp430f2618 DMA address assignment