UARTE DMA keeps clock active

[robvl]

Hi,

for a new project we use the NRF52480, I can get it into low power mode with a total use of 20µA ( with all the other hardware on the board ).
But when I initialize the UARTE, even without communicating, the current consumption jumps to 610µA when i trie to go into deepsleep.

when I initialize a normal UART, there is no problem and the power consumpion goes back to 20µA after communicating.

I guess the DMA is blocking my program to go into deep sleep mode.
I have already tried disabling the UARTE peripheral even after waiting for the last writing action of the DMA but nothing seems to work.

Is there a way to disable the DMA or something? or is the DMA not the issue here?

Thanks and Regards, Rob

[Sigurd]

Hi,

robvl said:

I have already tried disabling the UARTE peripheral even after waiting for the last writing action of the DMA but nothing seems to work.

Did you use nrfx_uarte_uninit() / nrf_drv_uart_uninit() for this ?

If yes, make sure that use the latest version of nrfx. The new driver version now waits for TX_STOPPED event before disabling the peripheral. This gracefully uinit of the UARTE peripheral was introduced in nrfx v1.7.2. See this link. (Note that SDK 15.3 is bundled with nrfx v1.6.2)