UARTs and EASY DMA

RE: UARTs and EASY DMA

Amanda Hsieh — Fri, 29 Nov 2019 08:56:07 GMT

You could use nrfx_uart_uninit to uninitialize the UART driver.

-Amanda H.

RE: UARTs and EASY DMA

abe — Fri, 29 Nov 2019 08:47:59 GMT

Amanda,

I readed both link you sent me. In the UART driver handling article for nRF52 yuo can understand the current sink in the following two case:
- UARTE with DMA --> average 1.3mA
- UART (Legacy) --> average 373uA
These are EXACTLY the currents I have measured on my application for the two method above quoted.
I think that the only way to reduce the current sink is to disable the UART
It's right? How can I disable the UART?

RE: UARTs and EASY DMA

Amanda Hsieh — Fri, 29 Nov 2019 08:13:11 GMT

Hi,

[quote user=""]- I'm not be able to configure both instance using NRF_SERIAL_CONFIG_DEF macro with parameter NRF_SERIAL_MODE_IRQ.[/quote]

That's right. UART1 is not supported. Serial peripheral with number 1 is only UARTE1 in nRF52840 SoC.

[quote user=""]- Instead, if I use the NRF_SERIAL_CONFIG_DEF macro with parameter NRF_SERIAL_MODE_DMA the two UART instances work well.[/quote]

You also can take a look at this Serial Port Library Example with two UARTEs example.

[quote user=""]How can I have few uA of CPU current comsumption even with UARTs enabled?[/quote]

if you use the UART, it needs to turn on the UART (50uA) from the Product spec + high frequency clock.

https://jimmywongbluetooth.wordpress.com/2019/04/17/overview-uart-driver-handling-at-nrf52/

My colleague did some measurements on the Legacy UART or UART with DMA.

Please also see this post.

Could you show us who you measured the current? What is the code you use?

-Amanda H.