MSP430FR5969: An ADC12 and DMA issue in lowpower mode

Cherry Zhou

Part Number: MSP430FR5969

The customer would like to know if the cpu works in lpm( low-power-mode), and the customer wanna use adc-12 to keep measuring a successive signal then store it into a flash outside the mpu. Is it possible to just use DMA to achieve this goal instead of awaking CPU?

Thanks a lot!

Best Regards,

Cherry Zhou

over 4 years ago

0 Bruce McKenney over 4 years ago

Guru 100785 points

The DMA can be used with the ADC, operating in the background with the CPU in LPM. I don't see an Example for the FR5994, but here's an example for the F5 series, which has a similar ADC and DMA:

https://dev.ti.com/tirex/explore/node?node=ALkqBIa6R80LFOC7XAng.Q__IOGqZri__LATEST

The FR5994 doesn't have an external bus (EMIF), so writing to an external flash would presumably use a serial port -- probably SPI. This can also be done with the DMA, but coordination with the ADC DMA would require some CPU intervention. (I don't know of a TI Example.)

0 Gary Gao over 4 years ago in reply to Bruce McKenney

TI__Mastermind 39860 points

For the ADC with DMA in LPM, I have a project that I created before with FR5994 that you can take as a reference

adc_dma_with_lea_4k.zip

For the second question agree with Bruce, it is need CPU to do that.

0 Cherry Zhou over 4 years ago in reply to Gary Gao

TI__Mastermind 22235 points

Hi Bruce and Gary,

Thank you all, and I have updated the answer to the customer.

If there is anything new I would follow up asap.

Thanks,

Best Regards,

Cherry

0 Cherry Zhou over 4 years ago in reply to Cherry Zhou

TI__Mastermind 22235 points

Hi,

The customer has another question:

Can he read and write at the FRAM in MPU at the same time?

Because he wanna keep the ADC measuring to FRAM and at the same time transmit the data in FRAM to the external flash.

Thanks for your help again!

Best Regards,

Cherry

0 Bruce McKenney over 4 years ago in reply to Cherry Zhou

Guru 100785 points

An address (range) can be configured for both read and write in the Memory Protection Unit (MPU).

DMA memory operations don't occur simultaneously, nor do CPU memory operations -- DMA operations happen in priority order, and the CPU is stalled during DMA.

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MSP430FR5969: An ADC12 and DMA issue in lowpower mode