sam3s16 ATMEL Corporation, sam3s16 Datasheet - Page 32

• Manufacturer Part Number: sam3s16
• Description: At91sam Arm-based Flash Mcu
• Manufacturer: ATMEL Corporation

10.5
Figure 10-2. Clock Generator Block Diagram
32
Clock Generator
SAM3S16 Preliminary
The Slow Clock generator is based on a 32 kHz crystal oscillator and an embedded 32 kHz RC
oscillator. The Slow Clock defaults to the RC oscillator, but the software can enable the crystal
oscillator and select it as the Slow Clock source.
The Supply Controller starts up the device by sequentially enabling the internal power switches
and the Voltage Regulator, then it generates the proper reset signals to the core power supply.
It also enables to set the system in different low power modes and to wake it up from a wide
range of events.
The Clock Generator is made up of:
• One Low Power 32768Hz Slow Clock oscillator with bypass mode
• One Low-Power RC oscillator
• One 3-20 MHz Crystal Oscillator, which can be bypassed
• One Fast RC oscillator factory programmed, 3 output frequencies can be selected: 4, 8 or 12
• One 80 to 240 MHz PLL (PLLB) providing a clock for the USB Full Speed Controller
• One 80 to 240 MHz programmable PLL (PLLA), capable to provide the clock MCK to the
MHz. By default 4 MHz is selected.
processor and to the peripherals. The PLLA input frequency is from 3 to 32 MHz.
XOUT32
XIN32
XOUT
XIN
Management
12/8/4 MHz
Slow Clock
3-20 MHz
Oscillator
RC OSC
Divider A
Controller
Clock Generator
PLL and
Oscillator
PLL and
Divider B
RC OSC
On Chip
On Chip
32 kHz
Power
Status
Main
Control
XTALSEL
Slow Clock
SLCK
Main Clock
MAINCK
MAINSEL
PLLB Clock
PLLBCK
PLLA Clock
PLLACK
11117AS–ATARM–12-Jul-11