ATSAM3S-EK Atmel, ATSAM3S-EK Datasheet - Page 424

• Manufacturer Part Number: ATSAM3S-EK
• Description: KIT EVAL FOR ATSAM3S4C
• Manufacturer: Atmel
• Series: SAM3Sr
• Type: MCUr

Specifications of ATSAM3S-EK

• Contents: Board, Cables, Power Supply
• Silicon Manufacturer: Atmel
• Core Architecture: ARM
• Core Sub-architecture: Cortex-M3
• Kit Contents: Board
• Features: TFT Colour LCD Display, SD/MMC Interface
• Svhc: No SVHC (15-Dec-2010)
• Rohs Compliant: Yes
• For Use With/related Products: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

25.5
424
Main Clock
SAM3S Preliminary
the XIN32 pin are given in the product electrical characteristics section. In order to set the
bypass mode, the OSCBYPASS bit of the Supply Controller Mode Register (SUPC_MR) needs
to be set at 1.
The user can set the Slow Clock Crystal Oscillator in bypass mode instead of connecting a crys-
tal. In this case, the user has to provide the external clock signal on XIN32. The input
characteristics of the XIN32 pin under these conditions are given in the product electrical char-
acteristics section.
The programmer has to be sure to set the OSCBYPASS bit in the Supply Controller Mode Reg-
ister (SUPC_MR) and XTALSEL bit in the Supply Controller Control Register (SUPC_CR).
Figure 25-3
Figure 25-3. Main Clock Block Diagram
The Main Clock has two sources:
• 4/8/12 MHz Fast RC Oscillator which starts very quickly and is used at startup
• 3 to 20 MHz Crystal or Ceramic Resonator-based Oscillator which can be bypassed
XOUT/PB8
Slow Clock
shows the Main Clock block diagram.
XIN/PB9
SLCK
MOSCRCEN
MOSCRCEN
Ceramic Resonator
MOSCXTCNT
Main Clock
MOSCXTEN
4/8/12 MHz
MOSCXTEN
Frequency
3-20 MHz
Oscillator
Oscillator
3-20 MHz
Oscillator
Fast RC
Counter
Counter
Crystal
or
MOSCRCF
MOSCSEL
MAINRDY
MOSCRCS
MOSCXTS
MOSCSEL
MAINF
0
1
Main Clock
MOSCSELS
MAINCK
6500C–ATARM–8-Feb-11