MSP430FR5739: The workaround for DMA9 errata of EXP430FR5739

Keigo Ishii

Part Number: MSP430FR5739

Hi,

The DMA9 errata of EXP430FR5739 has the following workaround:

2) When using DMA channel 0 for transferring data to and from the eUSCI_A or
eUSCI_B, use DMA channel 2 (lower priority than DMA channel 0) to read the same
register of the eUSCI_A or eUSCI_B that DMA channel 0 is working with. Use the same
USCI IFG (e.g. UCA0RXIFG) as trigger source for these both DMA channels.

Can this workaround prevent completely unexpected behavior on DMA9 errata?
In other words, is it possible to miss the trigger on DMA channel 2?

Best regards,
Keigo Ishii

over 7 years ago

0 Ryan Brown1 over 7 years ago

TI__Guru**** 205117 points

Hi Keigo Ishii,

This workaround completely prevents the unexpected behavior of the DMA9 errata and it not capable of missing a trigger. An EUSCI flag state is sometimes unexpectedly captured high during the 1st DMA transmission which will therefore prevent the DMA from further triggering, but by using a 2nd dummy DMA transmission it is ensured that this flag is immediately cleared so that DMA operation can continue as expected. The disadvantage to this solution is that two DMA channels must be used to successfully operate one channel.

Regards,
Ryan

0 Keigo Ishii over 7 years ago in reply to Ryan Brown1

Intellectual 820 points

Hi Ryan,

I got it, thank you for your answer.

Best regards,
Keigo Ishii

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MSP430FR5739: The workaround for DMA9 errata of EXP430FR5739