Atmel AT01607, Примечание к применению

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Atmel AT01607: XMEGA C Schematic ChecklistAtmel AT01607: XMEGA C Schematic Checklist
[APPLICATION NOTE]
8466A
−
AVR
−
06/2013
7
Figure 3-3. Real-time oscillator without load capacitor.
32.768kHz
TOSC1
TOSC2
Crystals specifying load capacitance (CL) higher than 3.0pF, require external capacitors applied as described in Figure
3-4 .
Figure 3-4. Real-time oscillator with load capacitor.
32.768kHz
18pF
18pF
TOSC1
TOSC2
To find suitable load capacitance for a 32.768kHz crystal, please consult the crystal datasheet.
Table 3-4. External real-time oscillator checklist.
Signal name Recommended pin connection Description
TOSC1 Load capacitor 18pF
(1)(2)
Timer oscillator pin 1
TOSC2 Load capacitor 18pF
(1)(2)
Timer oscillator pin 2
Notes: 1. These values are given only as a typical example. Please refer to the crystal datasheet to determine the
capacitor value for the crystal used or refer to the application notes “ AVR1003: Using the XMEGA Clock
System ” and “ AVR4100: Selecting and testing 32kHz crystal oscillators for Atmel AVR microcontrollers ”.
2.
Load capacitors should be placed close to the crystal, GND and device oscillator pins.