Accurate or custom baudrate on nrf9160

[Chraebs]

Hi

On a nrf9160, I need to send data via UART(E) at 921600 baud. According to the UARTE BAUDRATE register documentation the register value 0xF000000 (Baud921600) leads to an actual rate of 941176 Hz. This is also what I measure on the oscilloscope. Setting the BAUDRATE register to an interpolated value 0xEBEDFA4 seems to result still in approx. 940000. What is the recommended way to achieve more accurate baudrate 921600?

Follow-up question: Is it possible to use custom baud rates, or are only the baudrates listed in the UARTE BAUDRATE register documentation supported?

Thanks,
Matthias

[Chraebs]

I couldn't find that in the product specification, but most probably the UARTE frequencies are limited to the HFCLK frequency and possible divisors. As HFCLK is 16 MHz fractions of 16MHz is supported. I.e. closest frequencies to 921600 Hz are either 941176.5 (16MHz/17) or 888888.9 (16MHz/18).