Teil 1:
Even though the SPI Programming interface re-uses the SPI I/O module,
there is one important
difference: The MOSI/MISO pins that are mapped to PB2 and PB3 in the SPI
I/O module are not
used in the Programming interface. Instead, PE0 and PE1 are used for
data in SPI Programming
mode as shown in Table 127.
Teil 2:
As an alternative to using the RESET signal, PEN can be held low during
Power-on
Reset while SCK is set to “0”. In this case, only the PEN value at
Power-on Reset is
important. If the programmer cannot guarantee that SCK is held low
during power-up, the
PEN method cannot be used. The device must be powered down in order to
commence
normal operation when using this method.