SAM3S8C Atmel Corporation, SAM3S8C Datasheet - Page 440

• Manufacturer Part Number: SAM3S8C
• Manufacturer: Atmel Corporation

25.0.3
25.0.4
440
440
SAM3S8/SD8
SAM3S8/SD8
Block Diagram
Slow Clock
Figure 25-1. Clock Generator Block Diagram
The Supply Controller embeds a slow clock generator that is supplied with the VDDIO power
supply. As soon as the VDDIO is supplied, both the crystal oscillator and the embedded RC
oscillator are powered up, but only the embedded RC oscillator is enabled. This allows the slow
clock to be valid in a short time (about 100 µs).
The Slow Clock is generated either by the Slow Clock Crystal Oscillator or by the Slow Clock RC
Oscillator.
The selection between the RC or the crystal oscillator is made by writing the XTALSEL bit in the
Supply Controller Control Register (SUPC_CR).
XOUT32
XOUT
XIN32
XIN
(Supply C ontroller)
XTALSEL
Clock G ene rator
RC Oscillator
RC Oscillator
Management
Embedded
4/8/12 MHz
Embedded
Resonator
Status
32768 Hz
Oscill a tor
3-20 MHz
Oscilla tor
Ceramic
Controller
32 kHz
Crystal
Crystal
Power
Fast
or
Control
0
1
0
1
MOSCSEL
PLLB and
PLLA and
Divider /2
PLLBDIV2
PLLADIV2
Divider /2
Sl ow Clock
SLCK
Main Clo ck
MAINCK
PLLA Cloc
PLLACK
PLLB Cloc
PLLBCK
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12