Rabbit BL2020, User Manual

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User’s Manual 19
3.2.2 Digital Outputs
The BL2000 has 10 digital outputs, OUT0–OUT9, each of which can either sink or source
up to 200 mA, depending on how the outputs are configured. On boards that carry the CE
mark, OUT8 and OUT9 are each capable of sinking up to 750 mA.
Each output can be configured individually as either a sinking or a sourcing output as shown
in Figure 9. The outputs can be pulled as a group to Vcc, +K, or GND through 27 k
Ω
resis-
tors. Tie the outputs high to either Vcc or +K when using the outputs as sinking outputs (via
0
Ω
resistors at R32 or R35 respectively), or tie the outputs to GND via R34 when using the
outputs as sourcing outputs. +K is an externally supplied voltage of up to 40 V DC, and is
used primarily in combination with current sourcing outputs, and
must also be connected to
an external supply when an inductive load is connected to a sinking output.
NOTE: Remove the 27 k
Ω
resistors (R143–R150) from the output circuits if no pull-
up/down is required to avoid leakage between the outputs. These resistors are located
on the bottom side of the BL2000 board above the solder points for screw terminal
header J9.
Vcc
27 k W
Vcc
27 k W
K
SINKING OUTPUT—Factory Default
0 W
0 W
SOURCING OUTPUT—Special Order
K