Regulator Automatic Low-Power Mode

In Standby mode, the PM selects either the main or the low-power voltage regulator to supply the VDDCORE. If switchable power domain is in retention state, the low-power voltage regulator is used.

If a sleepwalking task is working on either asynchronous clocks (generic clocks) or synchronous clock (APB/AHB clocks), the main voltage regulator is used. This behavior can be changed by writing the Voltage Regulator Standby Mode bits in the Standby Configuration register (STDBYCFG.VREGSMOD). Refer to the following table for details.

Table 1. Regulator State in Sleep Mode




SleepWalking(1) Regulator state for VDDCORE
Active - - main voltage regulator
Idle - - main voltage regulator
Standby (active) 0x0: AUTO NO low-power regulator
YES main voltage regulator
0x1: PERFORMANCE - main voltage regulator
0x2: LP(2) -(2) low-power regulator
Standby (retention) - - low power regulator
  1. 1.SleepWalking is running on GCLK clock or synchronous clock. This is not related to XOSC32K or OSCULP32K clocks.
  2. 2.Must only be used when SleepWalking is running on GCLK with 32 KHz source.