Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
529
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
At start-up, the Main On-Chip RC Oscillator frequency is 4 MHz.
Note: MOSCRCF must be changed only if MOSCRCS is set in the 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.
• KEY: Write Access Password
• MOSCSEL: Main Oscillator Selection
0: The Main On-Chip RC Oscillator is selected.
1: The Main Crystal 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.
1: The Clock Failure Detector is enabled.
Note:
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.
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
Value
Name
Description
0x37
PASSWD
Writing any other value in this field aborts the write operation.
Always reads as 0.
Always reads as 0.