Datasheet

519
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
29.17.7 PMC Clock Generator Main Oscillator Register
Name: CKGR_MOR
Address: 0x400E0420
Access: Read/Write
This register can only be written if the WPEN bit is cleared in “PMC Write Protection Mode Register” .
• MOSCXTEN: Main Crystal Oscillator Enable
A crystal must be connected between XIN and XOUT.
0: The Main Crystal Oscillator is disabled.
1: The Main Crystal Oscillator is enabled. MOSCXTBY must be set to 0.
When MOSCXTEN is set, the MOSCXTS flag is set once the Main Crystal Oscillator start-up time is achieved.
• MOSCXTBY: Main Crystal Oscillator Bypass
0: No effect.
1: The Main Crystal Oscillator is bypassed. MOSCXTEN must be set to 0. An external clock must be connected on XIN.
When MOSCXTBY is set, the MOSCXTS flag in PMC_SR is automatically set.
Clearing MOSCXTEN and MOSCXTBY bits allows resetting the MOSCXTS flag.
• WAITMODE: Wait Mode Command
0: No effect.
1: Enters the device in Wait Mode.
Note: The WAITMODE bit is write-only.
• MOSCRCEN: Main On-Chip RC Oscillator Enable
0: The Main On-Chip RC Oscillator is disabled.
1: The Main On-Chip RC Oscillator is enabled.
When MOSCRCEN is set, the MOSCRCS flag is set once the Main On-Chip RC Oscillator start-up time is achieved.
• MOSCRCF: Main On-Chip RC Oscillator Frequency Selection
31 30 29 28 27 26 25 24
––––––CFDENMOSCSEL
23 22 21 20 19 18 17 16
KEY
15 14 13 12 11 10 9 8
MOSCXTST
76543210
– MOSCRCF MOSCRCEN WAITMODE MOSCXTBY MOSCXTEN