Rainbow Electronics ATmega163L - Manual (Page 6)

ATmega163(L)
6
Crystal Oscillator
XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier which can be configured for use as an on-
chip oscillator, as shown in Figure 2. Either a quartz crystal or a ceramic resonator may be used.
Figure 2. Oscillator Connections
External Clock
To drive the device from an external clock source, XTAL1 should be driven as shown in Figure 3.
Figure 3. External Clock Drive Configuration
External RC Oscillator
For timing insensitive applications, the external RC configuration shown in Figure 4 can be used. For details on how to
choose R and C, see Table 63 on page 140.
Figure 4. External RC Configuration
Timer Oscillator
For the Timer Oscillator pins, PC6(TOSC1) and PC7(TOSC2), the crystal is connected directly between the pins. No exter-
nal capacitors are needed. The oscillator is optimized for use with a 32,768 Hz watch crystal. Applying an external clock
source to the PC6 (TOSC1) pin is not recommended.
XTAL2
XTAL1
GND
C
R
V
CC
NC