5.
User Buttons and LEDs
The E20 has 3 user-programmable buttons, and 6 user-programmable tri-color LEDs.
GPIO 40: LED-A red
GPIO 41: LED-A green
GPIO 42: LED-B red
GPIO 43: LED-B green
GPIO 44: LED-C red
GPIO 45: LED-C green
GPIO 117: Button 1
GPIO 118: Button 2
GPIO 119: Button 3
For convenience, programs are pre-installed on the E20 to interact with these peripherals:
Controlling LEDs
•
Provided by package e20-leds:
o
/usr/local/bin/led-a
o
/usr/local/bin/led-b
o
/usr/local/bin/led-c
•
Usage:
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led-a red
o
led-a green
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led-a amber
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led-a off
Reading the buttons:
•
Provided by package e20-buttons:
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/usr/local/bin/button-1
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/usr/local/bin/button-2
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/usr/local/bin/button-3
•
Prints the button status (1 = up, 0 = pressed)
•
Also returns this number as the exit code
o
Can be retrieved via the shell environment variable
$?
immediately after execution.
SNAP Connect E20 Users Guide
5
Preliminary
- Pre-Release
Version
