29.5.3 Clocks

The clock for the FREQM bus interface (PB1_CLK) is enabled and disabled by the CRU generator.

Two generic clocks are used by the FREQM:
  • Reference Clock (GCLK_FREQM_REF – GCLK_FREQM_REF is required to clock the internal reference timer, which acts as the frequency reference.
  • Measurement Clock (GCLK_FREQM_MSR – GCLK_FREQM_MSR is required to clock a ripple counter for the frequency measurement. These clocks must be configured and enabled in the generic clock controller before using the FREQM.

See Clock and Reset Unit (CRU) from Related Links.