Datasheet

Table 28-7. External Multipurpose Crystal Oscillator Current Settings
Frequency Range
Current Setting
IMULT[3:0] IPTAT[1:0]
24MHz to 48MHz 6 3
16MHz to 24MHz 5 3
8MHz to 16MHz 4 3
8MHz 3 2
For relatively small CLOAD in a frequency range, the setting for the lower frequency range can be used
to preserve current consumption.
Bit 8 – LOWBUFGAIN Low Buffer Gain Enable
0: The low buffer gain of oscillator XOSCn is disabled.
1: The low buffer gain of oscillator XOSCn is enabled.
When XOSCCTRLn.ENALC=0 this bit has no effect.
When XOSCCTRLn.ENALC=1, this bit is used to adjust the oscillator's amplitude in automatic loop
control.
The default value of LOWBUFGAIN=0 should be used to allow operating with a low amplitude oscillator.
Use this setting except to solve stability issues.
Setting LOWBUFGAIN=1 will increase the oscillator's amplitude by a factor of approximately 2. Use this
setting to solve stability issues.
Bit 7 – ONDEMAND On Demand Control
The On Demand operation mode allows the oscillator XOSCn to be enabled or disabled, depending on
peripheral clock requests.
If On Demand is set, the oscillator will be running only when requested by a peripheral and enabled
(XOSCCTRLn. ENABLE=1). If there is no peripheral requesting the oscillator’s clock source, the oscillator
will be in a disabled state.
If On Demand is cleared, the oscillator will always be running when enabled (XOSCCTRLn.ENABLE=1).
In standby sleep mode, the On Demand operation is still active.
0: The oscillator is always on.
1: The oscillator is running when a peripheral is requesting the oscillator to be used as a clock source.
The oscillator is not running if no peripheral is requesting the clock source.
Bit 6 – RUNSTDBY Run in Standby
This bit controls how the XOSCn behaves during standby sleep mode:
0: The XOSCn is not running in standby sleep mode if no peripheral requests the clock.
1: The XOSCn is running in standby sleep mode. If ONDEMAND is one, the XOSCn will be running when
a peripheral is requesting the clock. If ONDEMAND is zero, the clock source will always be running in
standby sleep mode.
Bit 2 – XTALEN Crystal Oscillator Enable
This bit controls the connections between the I/O pads and the external clock or crystal oscillator XOSCn:
0: External clock connected on XIN. XOUT can be used as general-purpose I/O.
1: Crystal connected to XIN/XOUT.
SAM D5x/E5x Family Data Sheet
OSCCTRL – Oscillators Controller
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 797