External and miscellaneous requirements

For correct operation of the SoftDevice, it is a requirement that the crystal oscillator (HFXO) startup time is less than 1.5 ms.

The external clock crystal and other related components must be chosen accordingly. Data for the crystal oscillator input can be found in the relevant SoC product specification (S132 SoftDevice core documentation).

When the SoftDevice is enabled, the SEVONPEND flag in the SCR register of the CPU shall only be changed from main or low interrupt level (priority not higher than 4). Otherwise the behavior of the SoftDevice is undefined and the SoftDevice might malfunction.