DMA controller pitfalls
From Texas Instruments Embedded Processors Wiki
Byte access to the DMA controller registers
Although the family users guide for the MSP430F54xx states, that all DMA controller registers have byte access (and also introduces _L and _H aliases for byte-accessing the registers), this is not true. Any write to DMAxxx_H instead goes into the low byte (DMAxxx_L). The same is true for read access. Reading DMAxxx_H returns the low byte of the register.
While this is not a problem in most cases, it is necessary to write the DMA triggers for DMA0 and DMA1 together into DMACTL0 using a word write. It is not possible to set them independently by writing to DMACTL0_L and DMACTL0_H.
Use
DMACTL0=(DMACTL0&0xff00)|(trigger&0xff);
for setting the trigger for DMA0 and
DMACTL0=(DMACTL0&0x00ff)|(trigger<<8);
for setting the trigger for DMA1.
This issue has been reported to TI and will be addressed in version F of the MSP430X5xx family user's guide SLAU208.
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