TOSC Switch

On the ATmega128(L) the TOSC1 and TOSC2 lines are shared with Port G (PG4 and PG3). The TOSC switch select if the 32 kHz crystal, or the Port G connector pins should be connected to the pins on the device.

Figure 1 shows a simplified block schematic on how this is implemented.

Note:

Port G is not available on the ATmega103(L), the switch will thus only select if the 32 kHz crystal should be connected or not.

Figure 1. TOSC Block Schematic