27.6.2 Low-Power Mode Pin Control

The SHDWC manages the LPM pin which is used to indicate to an external power supply to enter or exit a special powering state. The LPM pin can be configured by software or by hardware.

To configure LPM with software:

• Set SHDWC_CR.LPMEN to set LPM 'high' (VBAT level)
• Set SHDWC_CR.LPMDIS to set LPM 'low' (VBAT level)

Writing both SHDW_CR.LPMEN and SHDW_CR.LPMDIS has no effect.

For LPM configuration via hardware, SHDW_MR.AUTOLPM must be set to '1'. The configuration is done automatically by the SHDWC and the RSTC when entering and exiting ULP2 mode:

• The LPM pin is set 'high' when the system enters ULP2 mode
• The LPM pin is set 'low' when the system exits ULP2 mode

By default, at the first power-up, LPM starts at lowlevel.