How to configure UART with low power

[fanleung]

Now I'm using NRF52832 to communicate with other MCU(STM32) by UART.

STM32 will transmits about 40 bytes data to NRF52832 per 10ms.

Here is my configure referenced Nordic\nRF5_SDK_12.0.0_12f24da\examples\ble_peripheral\ble_app_uart

static void uart_init(void)
{
    uint32_t                     err_code;
    const app_uart_comm_params_t comm_params =
    {
        RX_PIN_NUMBER,
        TX_PIN_NUMBER,
        RTS_PIN_NUMBER,
        CTS_PIN_NUMBER,
        APP_UART_FLOW_CONTROL_DISABLED,
        false,
        UART_BAUDRATE_BAUDRATE_Baud115200
    };

    APP_UART_FIFO_INIT( &comm_params,
                       UART_RX_BUF_SIZE,
                       UART_TX_BUF_SIZE,
                       uart_event_handle,
                       APP_IRQ_PRIORITY_LOW,
                       err_code);
    APP_ERROR_CHECK(err_code);
}

And the Current jump to 2.5mA... I have read the Specification and I found the UART electrical specification as follows:

What's wrong with my configure? Does anyone help me?

[thischier]

I guess that you forgot the shared resources and other power consumption which is added to the above mentioned electrical characteristics...

For example, when you are sending some data over UART and haven't configured the UART with easy DMA, your processor is running and you need to add the power consumption of the CPU, the same with the needed crystals etc...

[fanleung]

Hi, thank you for answer.

Howerve, if I delete uart_init(), the current is nearly 20uA and 200uA while advertising and connected.

I used to use SPI peripherals on other products to drive Sensor chip, and connect the phone to send the same size data, the total current is only 2.4mA. I think the UART is the internal peripherals, and it should be lower power.

Accoding to your description, do you think UART cost 2.4mA is normal ?

Or do you have any suggestion for me to low the current ?

thanks again!

[Nate]

Did you figure this out? I am running into the same issues with power and the uart and my numbers are almost the same as yours as far as power with the uart enabled and disabled