[spot an]Das soll es so etwas wie eine JTAG Interface geben ![spot aus]
Das kannst Du per Fuse-Bits abschalten, dann klappt das auch mit den
Pins.
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Port C (PC7..PC0)
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Port C is an 8-bit bi-directional I/O port with internal pull-up
resistors (selected for each bit). The Port C output buffers have
symmetrical drive characteristics with both high sink and source
capability. As inputs, Port C pins that are externally pulled low will
source current if the pull-up resistors are activated.
The Port C pins are tri-stated when a reset condition becomes active,
even if the clock is not running. If the JTAG interface is enabled, the
pull-up resistors on pins PC5(TDI), PC3(TMS) and PC2(TCK) will be
activated even if a reset occurs.
Port C also serves the functions of the JTAG interface and other special
features of the ATmega16 as listed on page 61.
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