Data Sheet

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Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181G–SAM-D21_Datasheet–09/2015
z Bit 20 – DIVSEL: Divide Selection
This bit is used to decide how the clock source used by the generic clock generator will be divided. If the clock
source should not be divided, the DIVSEL bit must be zero and the GENDIV.DIV value for the corresponding
generic clock generator must be zero or one.
0: The generic clock generator equals the clock source divided by GENDIV.DIV.
1: The generic clock generator equals the clock source divided by 2^(GENDIV.DIV+1).
z Bit 19 – OE: Output Enable
This bit is used to enable output of the generated clock to GCLK_IO when GCLK_IO is not selected as a source in
the GENCLK.SRC bit group.
0: The generic clock generator is not output.
1: The generic clock generator is output to the corresponding GCLK_IO, unless the corresponding GCLK_IO is
selected as a source in the GENCLK.SRC bit group.
z Bit 18 – OOV: Output Off Value
This bit is used to control the value of GCLK_IO when GCLK_IO is not selected as a source in the GENCLK.SRC
bit group.
0: The GCLK_IO will be zero when the generic clock generator is turned off or when the OE bit is zero.
1: The GCLK_IO will be one when the generic clock generator is turned off or when the OE bit is zero.
z Bit 17 – IDC: Improve Duty Cycle
This bit is used to improve the duty cycle of the generic clock generator when odd division factors are used.
0: The generic clock generator duty cycle is not 50/50 for odd division factors.
1: The generic clock generator duty cycle is 50/50.
z Bit 16 – GENEN: Generic Clock Generator Enable
This bit is used to enable and disable the generic clock generator.
0: The generic clock generator is disabled.
1: The generic clock generator is enabled.
z Bits 15:13 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always write these bits to
zero when this register is written. These bits will always return zero when read.
z Bits 12:8 – SRC[4:0]: Source Select
These bits define the clock source to be used as the source for the generic clock generator, as shown in Table 14-
7.