Help¶

Due to Anomaly 132 LF RC source may not start if restarted in certain window after stopping (230 us to 330 us). Software reset also stops the clock so if clock is initiated in certain window, the clock may also fail to start at reboot. A delay is added before starting LF clock to ensure that anomaly conditions are not met. Delay should be long enough to ensure that clock is started later than 330 us after reset. If crystal oscillator (XO) is used then low frequency clock initially starts with RC and then seamlessly switches to XO which has much longer startup time thus, depending on application, workaround may also need to be applied. Additional drivers initialization increases initialization time and delay may be shortened. Workaround is disabled by setting delay to 0.

Direct dependencies¶

NRF52_ANOMALY_132_WORKAROUND && SOC_FAMILY_NRF

(Includes any dependencies from ifs and menus.)

Default¶

330

Kconfig definition¶

At <Zephyr>/soc/arm/nordic_nrf/nrf52/Kconfig.soc:484

Included via <Zephyr>/Kconfig:8 → <Zephyr>/Kconfig.zephyr:28 → <Zephyr>/soc/Kconfig:11 → <BuildDir>/Kconfig/Kconfig.soc.arch:2 → <Zephyr>/soc/arm/nordic_nrf/Kconfig:17

Menu path: (Top) → Hardware Configuration

config NRF52_ANOMALY_132_DELAY_US
    int "Anomaly 132 workaround delay (microseconds)"
    range 0 330
    default 330
    depends on NRF52_ANOMALY_132_WORKAROUND && SOC_FAMILY_NRF
    help
      Due to Anomaly 132 LF RC source may not start if restarted in certain
      window after stopping (230 us to 330 us). Software reset also stops the
      clock so if clock is initiated in certain window, the clock may also fail
      to start at reboot. A delay is added before starting LF clock to ensure
      that anomaly conditions are not met. Delay should be long enough to ensure
      that clock is started later than 330 us after reset. If crystal oscillator
      (XO) is used then low frequency clock initially starts with RC and then
      seamlessly switches to XO which has much longer startup time thus,
      depending on application, workaround may also need to be applied.
      Additional drivers initialization increases initialization time and delay
      may be shortened. Workaround is disabled by setting delay to 0.

(The ‘depends on’ condition includes propagated dependencies from ifs and menus.)