AT32UC3L-EK Atmel, AT32UC3L-EK Datasheet - Page 198

• Manufacturer Part Number: AT32UC3L-EK
• Description: KIT EVAL AVR32 UC3 MCU
• Manufacturer: Atmel
• Type: MCUr

Specifications of AT32UC3L-EK

• Contents: *
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: UC3L
• Kit Contents: Board
• Features: USB / Battery Powered, Board Controller / Bootloader
• Svhc: No SVHC (15-Dec-2010)
• Rohs Compliant: Yes
• Tool Type: Starter Kit
• Cpu Core: AVR 8
• Data Bus Width: 8 bit
• Processor Series: AT32
• Processor To Be Evaluated: AT32UC3L064
• Interface Type: USB, Capacitive Touch
• For Use With/related Products: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

13.5.13.1
13.5.13.2
13.5.13.3
13.5.13.4
13.5.14
32099F–11/2010
Interrupts
Enabling a generic clock
Disabling a generic clock
Changing clock frequency
Generic clock allocation
Figure 13-6. Generic Clock Generation
A generic clock is enabled by writing a one to the Clock Enable bit (CEN) in the Generic Clock
Control Register (GCCTRL). Each generic clock can individually select a clock source by writing
to the Oscillator Select field (OSCSEL). The source clock can optionally be divided by writing a
one to the Divide Enable bit (DIVEN) and the Division Factor field (DIV), resulting in the output
frequency:
where f
generic clock.
A generic clock is disabled by writing a zero to CEN or entering a sleep mode that disables the
PB clocks. In either case, the generic clock will be switched off on the first falling edge after the
disabling event, to ensure that no glitches occur. After CEN has been written to zero, the bit will
still read as one until the next falling edge occurs, and the clock is actually switched off. When
writing a zero to CEN the other bits in GCCTRL should not be changed until CEN reads as zero,
to avoid glitches on the generic clock. The generic clocks will be automatically re-enabled when
waking from sleep.
When changing the generic clock frequency by changing OSCSEL or DIV, the clock should be
disabled before being re-enabled with the new clock source or division setting. This prevents
glitches during the transition.
The generic clocks are allocated to different functions as shown in the “Generic Clock Allocation”
table in the SCIF Module Configuration section.
The SCIF has 14 interrupt sources:
• AE - Access Error:
S ources
G eneric
C lock
– A protected SCIF register was accessed without first being correctly unlocked.
SRC
O S C S E L
is the frequency of the selected source clock, and f
f
S R C
D ivider
D IV
f
GCLK
=
----------------------------
2 DIV
(
f
SRC
D IV E N
+
0
1
1
)
AT32UC3L016/32/64
S leep C ontroller
GCLK
M ask
is the output frequency of the
C E N
G eneric C lock
f
G C LK
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