TWR-RF-SNAP User’s Manual
Page 9 of 22
3.3
On-board Sensors, Inputs, and Indicators
The following interfaces are implemented in the TWR-RF-SNAP to allow for user interaction.
Temperature Sensor:
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Connected to ADC Ch. 1 (physical pin 9 of the SM700) – SNAP GPIO 31
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Low-Power Linear Active Thermistor IC
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Analog output
Photocell (Light Sensor):
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Connected to ADC Ch. 0 (physical pin 8 of the SM700) – SNAP GPIO 30
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Analog output
Power Switch:
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Left position – Draws power from the battery connector
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Middle position – OFF
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Right position – Draws power from the tower elevator or USB port
User LED 1 (Red):
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Connected to TMR0 (physical pin 34 of the SM700) – SNAP GPIO 8
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Activated by setting the pin HIGH
User LED2 (Green):
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Connected to TMR1 (physical pin 33 of the SM700) – SNAP GPIO 9
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Activated by setting the pin HIGH
Power LED:
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Green LED (D5) will indicate when power is applied to the board
Switch 2 (software accessible input):
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Connected to Physical Pin 57 of the SM700 – SNAP GPIO 22
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KBI pin – wake from sleep interrupt capable
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Switch is grounded when pressed
Switch 3 (software accessible input):
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Connected to Physical Pin 56 of the SM700 – SNAP GPIO 23
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KBI pin – wake from sleep interrupt capable
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Switch is grounded when pressed
Reset Button:
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Push button tied directly to RESET on the SM700 / Reboots the device
