ATSAM3U-EK Atmel, ATSAM3U-EK Datasheet - Page 456

Manufacturer Part Number

KIT EVAL FOR AT91SAM3U CORTEX

Manufacturer

Processor To Be Evaluated

Data Bus Width

Interface Type

Operating Supply Voltage

Silicon Manufacturer

Core Architecture

Core Sub-architecture

Silicon Core Number

Silicon Family Name

Kit Contents

Board CD Docs

Rohs Compliant

For Use With/related Products

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

Manufacturer

Part Number:

Manufacturer:

SAM3U Series

4/8/12 MHz Fast RC Oscillator

Figure 27-3. 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

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 Oscillator, which can be bypassed

shows the Main Clock block diagram.

3-20 MHz Crystal

6430D–ATARM–25-Mar-11