NRF51422: UART performance low, how to improve?

[Vehring]

Hello.

I´ve got problems with a via BLE connected IMU and data transfer over UART. I´ve now tried several methods to implement UART connection but with the given baudrate (115200) the application can´t send the received data over UART fast enough to not loose data from the IMU. The IMU is sending data at 50Hz but the UART is not able to send one string of 37char fast enough. When the UART has finished almost 70ms have passed, so i loose information.

I tried:

app_uart_fifo method uart_putchar (link text) nrf_drv_uart_tx (in blocking mode)

The priority, if usable, was always set to HIGHEST. The uart_putchar worked faster than the others but is not reliable in race conditions.

Why is the UART so slow (i assume much softdevice interrupts) and how can i make it such performant that i can send the data faster?

[Vehring]

Okay maybe i found the answer myself. I was neglecting to modify the ble connection parameters. setting lower connection intervals releases processing time from the softdevice so my uart transmits much faster

[bjorn-spockeli]

@vehring: Glad to hear that you have found a solution. It could also be an idea to increase the baudrate(given that the IMU supports this) so that the bytes are sent faster.