NRF52 Series Devices
On the nRF52 series devices from Nordic Semiconductor, SWO is supported. However, a few device specifics apply which are described in the following section.
For most devices, the SWO clock is derived from the current MCU clock. This is also the case for the nRF52 series devices. However on these devices, the SWO clock has an additional fixed divider. So when the MCU Clock is set to maximum 64 MHz the SWO clock is only maximum half of that which is 32 MHz. Depending of the setting in the TRACECONFIG register, this value can get divided down even further.
Note: J-Link handles the current setting of this register automatically when calculating the SWO speed to be used. J-Link software version V6.30i or later is required.
Note: When selecting the CPU frequency in IDEs for J-Link SWO usage, select 64 MHz for the nRF52 series devices.
Sample projects that demonstrate SWO usage are available for the following eval board: PCA10040
This project was created with Embedded Studio V3.40. The SWO print stream can be made visible by either using JLinkSWOViewer or Ozone with the project enclosed in the Embedded Studio project.