33.22.8 PMC Clock Generator Main Oscillator Register

This register can only be written if the WPEN bit is cleared in the PMC Write Protection Mode Register.

Name:	CKGR_MOR
Offset:	0x0020
Reset:	0x01000021
Property:	Read/Write


Bit	31	30	29	28	27	26	25	24
						XT32KFME	CFDEN	MOSCSEL
Access						R/W	R/W	R/W
Reset						0	0	1


Bit	23	22	21	20	19	18	17	16
	KEY[7:0]
Access	W	W	W	W	W	W	W	W
Reset	0	0	0	0	0	0	0	0


Bit	15	14	13	12	11	10	9	8
	MOSCXTST[7:0]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0


Bit	7	6	5	4	3	2	1	0
		ZERO	ONE	ZERO	MOSCRCEN	WAITMODE	MOSCXTBY	MOSCXTEN
Access		R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset		0	1	0	0	0	0	1

Bit 26 – XT32KFME 32.768 kHz Crystal Oscillator Frequency Monitoring Enable

Value	Description
0	The 32.768 kHz crystal oscillator frequency monitoring is disabled.
1	The 32.768 kHz crystal oscillator frequency monitoring is enabled.

Bit 25 – CFDEN Clock Failure Detector Enable

Value	Description
0	The clock failure detector is disabled.
1	The clock failure detector is enabled.

Bit 24 – MOSCSEL Main Clock Oscillator Selection

Value	Description
0	The 12 MHz RC oscillator is selected.
1	The 8 to 24 MHz crystal oscillator is selected.

Bits 23:16 – KEY[7:0] Password

Value	Name	Description
0x37	PASSWD	Writing any other value in this field aborts the write operation.

Bits 15:8 – MOSCXTST[7:0] 8 to 24 MHz Crystal Oscillator Start-up Time

Specifies the number of Slow clock cycles multiplied by 8 for the crystal oscillator start-up time.

Bit 5 – ONE Must Be Set to 1

Bit 5 must always be set to 1.

Bits 4, 6 – ZERO Must Be Set to 0

Bits 4 and 6 must always be configured to 0.

Bit 3 – MOSCRCEN 12 MHz RC Oscillator Enable

When MOSCRCEN is set, the MOSCRCS flag is set once the RC oscillator start-up time is achieved.

Value	Description
0	The 12 MHz RC oscillator is disabled.
1	The 12 MHz RC oscillator is enabled.

Bit 2 – WAITMODE ULP1 Mode Command (Write-only)

Value	Description
0	No effect.
1	Puts the device in ULP1 mode.

Bit 1 – MOSCXTBY 8 to 24 MHz Crystal Oscillator Bypass

When MOSCXTBY is set, the MOSCXTS flag in PMC_SR is automatically set.

Clearing MOSCXTEN and MOSCXTBY bits resets the MOSCXTS flag.

When Main Oscillator Bypass is disabled (MOSCXTBY = 0), the MOSCXTS flag must be read as 0 in PMC_SR prior to enabling the main crystal oscillator (MOSCXTEN = 1).

Value	Description
0	No effect.
1	The 8 to 24 MHz crystal oscillator is bypassed. MOSCXTEN must be cleared. An external clock must be connected on XIN.

Bit 0 – MOSCXTEN 8 to 24 MHz Crystal Oscillator Enable

A crystal must be connected between XIN and XOUT.

When MOSCXTEN is set, the MOSCXTS flag is set once the crystal oscillator start-up time is achieved.

Value	Description
0	The 8 to 24 MHz crystal oscillator is disabled.
1	The 8 to 24 MHz crystal oscillator is enabled. MOSCXTBY must be cleared.

SAMA5D29