UART and UARTE difference

[Somesh Burkule]

Hello,

I am using ble_app_uart example in sdk 15.2 and nrf52832.

I am using this example to communicate with other MCU. It is continuous Rx Tx between nrf52832 and other MCU.

By default, UART and UARTE( NRFX_UART_ENABLED and NRFX_UARTE_ENABLED)  is enable in sdkconfig.h.

but this really needs both? As I have read in documentation UARTE supports easyDMA which uses RAM.

I am getting communication error includes Framing Error and Break Error and in most of threads it points to UARTE.

Can you please tell me when to use UART and UARTE in application.

Does it really needs in my application?

What is the difference between UART and UARTE?

[Simonr]

Hi

The difference between UART and UARTE is that UARTE uses EasyDMA. You can configure examples to use either UART or UARTE in your application, but for the nRF52 series there's no reason to use UART over UARTE, as UARTE is both faster, has lower CPU usage, and consumes less power. For more details on UARTE, UARTE, and EasyDMA, please check out the product specification that goes more in-depth into these features.

Best regards,

Simon

[awneil]

So can you use UARTE, but not use the DMA ?

[Simonr]

Hi awneil

No, sorry if that wasn't clear. UARTE is Universal asynchronous receiver/transmitter (UART) with EasyDMA, so if you don't want DMA you will have to use the UART peripheral.

Best regards,

Simon

[eilon]

Hi @Simonr, 
I looked at the linked you attached, and I didn't see anything about the power consumption differences between UART and UARTE. 
From what I have read, using EasyDMA consume more power then the regular UART.

What am I missing?

- Eilon

[Simonr]

Hi Eilon

You're correct, the EasyDMA consumes ~1.2mA, but there are some pros to using EasyDMA, like lower CPU usage, less current consumption if the CPU gets to sleep, and more CPU time available for other timing-critical tasks, so it generally pays off to use EasyDMA. If you have more questions, please create a new ticket, as this case is ~2 years old at this point.

Best regards,

Simon