BL4S100 User’s Manual
20
Individual digital input channels may be also used for counters, synching, interrupts, input
capture, or as quadrature decoder inputs. The use of these channels for interrupts, input
capture, and as quadrature decoders is described below.
Blocks of digital input pins are associated with counters/timers on the Rabbit RIO chip.
Table 3 provides complete details for these associations.
Appendix D provides further details on the blocks and pins associated with the Rabbit
RIO chip to facilitate configuring each block consistently and to identify misconfigured
pins when a software function call returns a
Mode Conflict
error code.
The actual switching threshold is approximately
1.40 V. Anything below this value is a logic 0,
and anything above 1.90 V is a logic 1. The
digital inputs are each fully protected over a
range of -36 V to +36 V, and can handle short
spikes of ±40 V.
NOTE:
If the inputs are pulled up to +K, the
voltage range over which the digital inputs are
protected changes to +K – 36 V to +36 V.
Figure 7. BL4S100 Digital Input
Protected Range
CAUTION:
Do not allow the voltage on a digital input pin to exceed ±36 V to
avoid damaging the input.
Table 3. Counter/Timer Associations for BL4S100 Digital Input Pins
Configurable I/O
Pin(s)
Counter/Timer
Blocks
Block Shared
With
IN0–IN2
0
XBee RF module
IN3–IN5
1
—
IN6–IN7
2
OUT0–OUT1
IN8–IN9
3
OUT2–OUT3
IN10
6
—
IN11
7
—
+40 V
+36 V
+3.3 V
40 V
Normal Switching
Levels
Spikes
Digital Input V
oltage
Spikes
Spikes
