Rabbit Smartcat, User Manual

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User’s Manual 33
3.9 Other Hardware
3.9.1 External Interrupts
The BL2100 is already configured to support external interrupts on pin 11 of screw-terminal
header J11. The external interrupt circuit is shown in Figure 22.
Figure 22. Use of Rabbit 2000 External Interrupt
In addition to its primary use as an external interrupt, pin 11 of screw-terminal header J11
may also be used as a CMOS-level digital input or output, or to generate a PWM signal.
When using pin 11 as a CMOS-level digital input or output, use the standard Rabbit 2000
register function configuration for PE5 (on Parallel Port E) to set this pin up for your
intended use. Be aware that there is no provision for protection against voltage spikes
while PE5 is pulled up to Vcc with a 27 k

pull-up resistor.
The sample program
PWM.C
in the Dynamic C
SAMPLES/BL2100
directory illustrates
how to use pin 11 of screw-terminal header J11 to generate a PWM signal.
Interrupt Request #1
INT1B
23
29
Interrupt Request #0
INT0B
24
30
Edge
Detectors
1 k W
External Interrupt
Request
Single-Interrupt Request
R66
J11
12
11
10