Particle Monitor One, Manual

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This is not necessary if your external peripherals are powered by 3V3 or CAN_5V.
By default, if power is applied at the VIN pin it will be used to power the Monitor One and charge
the built-in battery.
If you are supplying VIN from another, larger battery pack, and want to be able to disconnect the
VIN power supply to minimize current loss, you can do so using the following circuit in lieu of using
NFC2 as the relay pin, as the I/O Card does.
By disconnecting the VIN power supply, it reduces the current used by the VIN and PMIC voltage
regulators. The Monitor One can still be powered by its internal LiPo battery. This is particularly
advantageous if the Monitor One is in sleep mode while VIN is disconnected as the power supply
loss will be large compared to the very low sleep current in this scenario.
Pin Monitor One Tracker One
A0
I2C SDA
1
Internal Thermistor
A1
I2C SCL
1
User Button (not accessible)
A2 External Button GNSS lock indicator
A3 Battery Temperature M8 Analog in, GPIO
A4
Analog in, GPIO, PWM, SPI MOSI
1
Not available
A5
Analog in, GPIO, PWM, SPI MISO
1
Not available
VIN DISABLE
GPIO AND PORTS VS. TRACKER ONE