ATSAM3X4EA-AU Atmel, ATSAM3X4EA-AU Datasheet - Page 538

• Manufacturer Part Number: ATSAM3X4EA-AU
• Description: ARM Microcontrollers - MCU QFP144,GREEN, IND TEMP, MRL A
• Manufacturer: Atmel

Specifications of ATSAM3X4EA-AU

• Rohs: yes
• Core: ARM Cortex M3
• Processor Series: SAM3X
• Data Bus Width: 32 bit
• Maximum Clock Frequency: 84 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 64 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 2.4 V to 3.6 V
• Operating Temperature Range: - 40 C to +85 C
• Package / Case: LQFP-144
• Mounting Style: SMD/SMT
• Factory Pack Quantity: 60

29.1.5
29.1.5.1
538
538
SAM3X/A
SAM3X/A
Main Clock
4/8/12 MHz Fast RC Oscillator
Figure 29-3
Figure 29-3. Main Clock Block Diagram
The Main Clock has two sources:
After reset, the 4/8/12 MHz Fast RC Oscillator is enabled with the 4 MHz frequency selected and
it is selected as the source of MAINCK. MAINCK is the default clock selected to start up the
system.
The Fast RC Oscillator 8 and 12 MHz frequencies are calibrated in production. Note that is not
the case for the 4 MHz frequency.
Please refer to the “DC Characteristics” section of the product datasheet.
The software can disable or enable the 4/8/12 MHz Fast RC Oscillator with the MOSCRCEN bit
in the Clock Generator Main Oscillator Register (CKGR_MOR).
The user can also select the output frequency of the Fast RC Oscillator, either 4 MHz, 8 MHz or
12 MHz are available. It can be done through MOSCRCF bits in CKGR_MOR. When changing
• 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.
Slow Clock
shows the Main Clock block diagram.
XOUT
SLCK
XIN
Main Clock
MAINCK
Ref.
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
11057B–ATARM–28-May-12
11057B–ATARM–28-May-12
MAINCK