16 |
P a g e
Each of the three input pins can be independently set to either have an internal 1.5k Pull Up or Pull Down and can be set to
be either Active High or Active Low. Internally supplied 3.3 power is available for biasing
Some typical Circuits are show below:
Relay or Switch
For Active High Select Normally Closed
For Active Low Select Normally Open
P.2/3/4
P.7
P.8
3.3V
Pu
ll U
p
Debounce
Capacitor
Suggested
P.2/3/4
P.7
P.8
3.3V
Pu
ll D
ow
n
Pulse / TTL Input
Do not Exceed
3.3V at Input Pin
For Active High Select Normally Open
For Active Low Select Normally Closed
Figure 25
NPN or N-MOS Transistor
Input
For Active High Select Normally Closed
For Active Low Select Normally Open
P.2/3/4
P.7
P.8
3.3V
Pu
ll U
p
P.2/3/4
P.7
P.8
3.3V
Pu
ll D
ow
n
PNP or P-MOS Transistor
Input
For Active High Select Normally Open
For Active Low Select Normally Closed
Vext
Optional
External
Power
Do not
Exceed
3.3V at
Input Pin
Figure 27
3
150 mA max. Using internal power or internal pullups will reduce battery life.
Figure 24
Figure 26
