at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 348

• Manufacturer Part Number: at91sam9263
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

Figure 26-2. Main Oscillator Block Diagram
26.3.1
Figure 26-3. Typical Crystal Connection
26.3.2
26.3.3
348
AT91SAM9263 Preliminary
Main Oscillator Connections
Main Oscillator Startup Time
Main Oscillator Control
The Clock Generator integrates a Main Oscillator that is designed for a 3 to 20 MHz fundamental
crystal. The typical crystal connection is illustrated in
trical characteristics of the Main Oscillator, see the section “DC Characteristics” of the product
datasheet.
The startup time of the Main Oscillator is given in the DC Characteristics section of the product
datasheet. The startup time depends on the crystal frequency and decreases when the fre-
quency rises.
To minimize the power required to start up the system, the main oscillator is disabled after reset
and slow clock is selected.
The software enables or disables the main oscillator so as to reduce power consumption by
clearing the MOSCEN bit in the Main Oscillator Register (CKGR_MOR).
Slow Clock
XOUT
SLCK
XIN
XIN
AT91 Microcontroller
Main Clock
OSCOUNT
Frequency
Oscillator
MOSCEN
Oscillator
XOUT
Counter
Counter
Main
Main
1K
GND
Main Clock
MAINCK
Figure
MAINRDY
MOSCS
MAINF
26-3. For further details on the elec-
6249D–ATARM–20-Dec-07