Select this option to use the very low power oscillator (VLO) as the conversion timer in wake-on-proximity mode in LPM4. This option may be used to reduce the average current in wake-on-proximity mode for designs that do not have a crystal oscillator.

If this option is defined, LPM4 will be selected as the power mode during wake-on-proximity operation, disabling ACLK and along with it XT1 or the REFO, whichever was sourcing ACLK previously, while the system is in WOP mode. When WOP mode is exited and active mode is entered, ACLK will again be utilized to source the conversion timer and the application-selected low power mode (g_uiApp.ui8AppLPM) will be used until WOP mode is again entered.

Notes

If this mode is selected and the VLO is used, the tolerance on the measured scan period will be poor. For example, if 10 Hz (100ms) is the selected WOP scan rate, this value may vary by as much as +/- 5 Hz across temperature and voltage. If this variance is too great for the application requirements, a 32kHz crystal or the REFO should be used instead.