7
ATmega103(L)
0945G–09/01
External Clock
To drive the device from an external clock source, XTAL2 should be left unconnected
while XTAL1 is driven as shown in Figure 3.
Figure 3.
External Clock Drive Configuration
Timer Oscillator
For the Timer Oscillator pins, TOSC1 and TOSC2, the crystal is connected directly
between the pins. No external capacitors are needed. The oscillator is optimized for use
with a 32,768 Hz watch crystal. Applying an external clock source to TOSC1 is not
recommended.
XTAL2
XTAL1
GND
NC
EXTERNAL
OSCILLATOR
SIGNAL