Baudrate on VCOM on nRF52840DK

RE: Baudrate on VCOM on nRF52840DK

Kenneth — Mon, 28 Jun 2021 12:23:05 GMT

The nRF52840 UART hardware supports the baudrate listed here:
https://infocenter.nordicsemi.com/topic/ps_nrf52840/uarte.html#register.BAUDRATE

As you can see, the actual baudrate when configured as 921600 differ some from the ideal, the actual is 941176 due to internal clock generation. Likely this prevent the SEGGER chip to not receive the data reliably on the nRF52840-DK.

Kenneth

RE: Baudrate on VCOM on nRF52840DK

mmajchrzycki — Sat, 26 Jun 2021 08:58:55 GMT

Yes, I mean the VCOM over the JLink. I'm curious, because the DKs manuals only mention that 921600 bps is not supported. There is nothing like "higher than". So, what about 1M which seems to be working? Where is that limitation come from?

RE: Baudrate on VCOM on nRF52840DK

Turbo J — Sat, 26 Jun 2021 08:43:33 GMT

Please clarifiy: Do you mean the Jlink COM port (USB->Jlink->NRF) or do you mean the CDC on the Nordic chip (USB->NRF chip)?

The UART on the Jlink chip has its own restrictions, AFAIK it can only do 115200 baud.