Description

The ztimer_msec module will take control of the RTT peripheral. This is a problem for applications that rely on the periph_rtt API to manually schedule wake from Deep Sleep:

• some driver schedules a wake-up in 10 ms
• The application decides to go to Deep Sleep (no RAM retained) and sets the RTT to reset the board in 1h, calls pm_set(0)
• The board will wake up from Deep Sleep after 10ms

It is also a problem for platforms where periph_rtc and periph_rtt share the same peripheral and only either of the two modes can be used.

See e.g. the sleepy node application for an example of such usage pattern.