18.5.1. I/O Lines
Not applicable.
18.5.2. Power Management
The FREQM will continue to operate in idle sleep modes where the selected source clock is running. The
FREQM’s interrupts can be used to wake up the device from idle sleep modes. Refer to the Power
Manager chapter for details on the different sleep modes.
18.5.3. Clocks
The clock for the FREQM bus interface (CLK_APB_FREQM) is enabled and disabled by the Main Clock
Controller, the default state of CLK_APB_FREQM can be found in the Peripheral Clock Masking section.
Two generic clocks are used by the FREQM(GCLK_FREQM_REF and GCLK_FREQM_MSR). The
reference clock (GCLK_FREQM_REF) is required to clock the internal reference timer while operating as
a frequency reference, while the measurement clock (GCLK_FREQM_MSR) is required to clock a ripple
counter for frequency measurement. These clocks must be configured and enabled in the generic clock
controller before using the FREQM.
Related Links
on page 141
on page 145
GCLK - Generic Clock Controller
on page 121
18.5.4. DMA
Not applicable.
18.5.5. Interrupts
The interrupt request line is connected to the interrupt controller. Using FREQM interrupt requires the
interrupt controller to be configured first.
18.5.6. Events
Not applicable
18.5.7. Debug Operation
When the CPU is halted in debug mode the FREQM continues normal operation. If the FREQM is
configured in a way that requires it to be periodically serviced by the CPU through interrupts or similar,
improper operation or data loss may result during debugging.
18.5.8. Register Access Protection
All registers with write-access can be write-protected optionally by the Peripheral Access Controller
(PAC), except the following registers:
•
Control B register (CTRLB)
•
Interrupt Flag Status and Clear register (INTFLAG)
•
Status register (STATUS)
Optional write-protection by the Peripheral Access Controller (PAC) is denoted by the "PAC Write-
Protection" property in each individual register description.
Write-protection does not apply to accesses through an external debugger.
Related Links
PAC - Peripheral Access Controller
on page 50
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
167