User's Manual

Version 1.0 - 2006-08 49
A.2.3.4 Switch-0 Signal
Switch-0 is not multiplexed with other functionality and a switch is easily implemented (see
Figure 30).
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 120kΩ). A design that prevents this can be found in Figure 31.
The Switch-0 pin can be left unconnected if its functionality is not used.
Figure 30: A low resistance function switch
used.
Figure 31: If the resistance in the switch is not
guaranteed to be low enough, a safer design
can be used.
A.2.4 Reset
The
RESET
pin can be connected to an external reset source, see Figure 32 for a switch
example.
If the reset signal is connected to an output signal it must be an open drain collector, see Figure
33. Notice the capacitive load on the
RESET
pin in Table 6, section 2.3.
The
RESET
pin can be left unconnected if not used.
Figure 32: A reset switch. Figure 33: Design of an open collector reset
from an active high output.