These are general I/O ports connected to ZIF socket and the TQFP footprint. On the ATmega169 the RESET-signal and PG5 share the same pin. The RST is the RESET-signal that comes from the STK500 board. Note that it is not directly connected to the ZIF socket or the TQFP footprint on the STK502. This because the RESET-signal on the STK500 has an pull-up resistor to VCCT which will interfere with PG5 when used as an ordinary I/O-pin.
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If the RESET/PG5-pin on ATmega169 shall be used as a Reset pin, the RST and PG5 on the PORTG RST must be connected with a jumper. See Figure 1.
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If the pin shall be used as an I/O-pin the jumper must be removed.
