505
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
• MOSCRCF: Main On-Chip RC Oscillator Frequency Selection
At start-up, the Main On-Chip RC Oscillator frequency is 4 MHz.
Note:
MOSCRCF must be changed only if MOSCRCS is set in PMC_SR register. Therefore MOSCRCF and MOSCRCEN cannot be
changed at the same time.
• MOSCXTST: Main Crystal Oscillator Start-up Time
Specifies the number of Slow Clock cycles multiplied by 8 for the Main Crystal Oscillator start-up time.
• MOSCSEL: Main Oscillator Selection
0 = The Main On-Chip RC Oscillator is selected.
1 = The Main Crystal Oscillator is selected.
• CFDEN: Clock Failure Detector Enable
0 = The Clock Failure Detector is disabled.
1 = The Clock Failure Detector is enabled.
Notes:
1. The slow RC oscillator must be enabled when the CFDEN is enabled.
2. The clock failure detection must be enabled only when system clock MCK selects the fast RC oscillator.
3. Then the status register must be read 2 slow clock cycles after enabling.
Value
Name
Description
0x0
4_MHz
The Fast RC Oscillator Frequency is at 4 MHz (default)
0x1
8_MHz
The Fast RC Oscillator Frequency is at 8 MHz
0x2
12_MHz
The Fast RC Oscillator Frequency is at 12 MHz
Summary of Contents for SAM4S Series
Page 44: ...44 11100B ATARM 31 Jul 12 SAM4S Series Preliminary ...
Page 412: ...412 11100B ATARM 31 Jul 12 SAM4S Series Preliminary ...
Page 1105: ...1105 11100B ATARM 31 Jul 12 SAM4S Series Preliminary ...
Page 1143: ...1143 11100B ATARM 31 Jul 12 SAM4S Series Preliminary Figure 43 4 64 lead LQFP Package Drawing ...
Page 1145: ...1145 11100B ATARM 31 Jul 12 SAM4S Series Preliminary Figure 43 5 64 lead QFN Package Drawing ...