ATEVK1105 Atmel, ATEVK1105 Datasheet - Page 58

• Manufacturer Part Number: ATEVK1105
• Description: KIT EVAL FOR AT32UC3A0
• Manufacturer: Atmel
• Series: AVR®32r
• Type: MCUr

Specifications of ATEVK1105

• Contents: Evaluation Board, Software and Documentation
• Processor To Be Evaluated: AT32UC3A0512
• Processor Series: AVR
• Data Bus Width: 32 bit
• Interface Type: USART, TWI, USB, SPI, Ethernet
• Operating Supply Voltage: 3.3 V
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: AVR UC3
• Silicon Core Number: AT32UC3A0512
• Silicon Family Name: AVR
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT32UC3A0
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

13.5.5
13.5.5.1
13.5.5.2
32058J–AVR32–04/11
PLL0 clock
Osc0 clock
Slow clock
Synchronous clocks
Selecting synchronous clock division ratio
Selecting PLL or oscillator for the main clock
MCSEL
The slow clock (default), Oscillator 0, or PLL0 provide the source for the main clock, which is the
common root for the synchronous clocks for the CPU/HSB, PBA, and PBB modules. The main
clock is divided by an 8-bit prescaler, and each of these four synchronous clocks can run from
any tapping of this prescaler, or the undivided main clock, as long as f
nous clock source can be changed on-the fly, responding to varying load in the application. The
clock domains can be shut down in sleep mode, as described in
Additionally, the clocks for each module in the four domains can be individually masked, to avoid
power consumption in inactive modules.
Figure 13-4. Synchronous clock generation
The common main clock can be connected to the slow clock, Oscillator 0, or PLL0. By default,
the main clock will be connected to the slow clock. The user can connect the main clock to Oscil-
lator 0 or PLL0 by writing the MCSEL bitfield in the Main Clock Control Register (MCCTRL). This
must only be done after that unit has been enabled, otherwise a deadlock will occur. Care
should also be taken that the new frequency of the synchronous clocks does not exceed the
maximum frequency for each clock domain.
The main clock feeds an 8-bit prescaler, which can be used to generate the synchronous clocks.
By default, the synchronous clocks run on the undivided main clock. The user can select a pres-
Prescaler
instruction
Sleep
CPUSEL
CPUDIV
0
1
Controller
Main clock
Sleep
CPUMASK
Mask
”Sleep modes” on page
CPU
AT32UC3A
f
PBA,B,
CPU clocks
HSB clocks
PBB clocks
PBAclocks
. The synchro-
60.
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