Version 1.17 2011-09
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Figure 25: No restore switch used but a green
LED in a 3.3V host system. The status of the
signal can also be used as input to a host con-
troller.
Figure 26: No restore switch used but a green
LED in a 5V host system. The status of the
signal can also be used as input to a host
controller.
A serial resistor to the restore switch must be used to prevent a short circuit when the
GREEN/Switch-1 pin is in output HIGH state and the switch is pressed (see Figure 27).
Sometimes, over time, switch contacts can get an oxide layer. This may cause the closed
switch resistance to become too high to sink the signal to logic LOW (the signal is internally
pulled-up to 16k&). A design that prevents this can be found in Figure 28.
The GREEN/Switch-1 pin can be left unconnected if none of its functionality is required.
Figure 27: A low resistance restore
switch used. Notice the 1k&
&  &
& serial resis-
tor.
Figure 28: If the resistance in the switch is not
guaranteed to be low enough, a safer design can
be used. Notice the 1k&
&  &
& serial resistor.
A.2.3.4 Switch-0 Signal
Switch-0 is not multiplexed with other functionality and a switch is easily implemented (see
Figure 29).
Sometimes, over time, switch contacts can get an oxide layer. This may cause the closed
switch resistance to become too high to sink the signal to logic LOW (the signal is internally
pulled-up to 16k&). A design that prevents this can be found in Figure 30.
The Switch-0 pin can be left unconnected if its functionality is not used.
Figure 29: A low resistance function switch
used.
Figure 30: If the resistance in the switch is not
guaranteed to be low enough, a safer design
can be used.