ELECTRON The Electron is a tiny cellular development kit based around U-Blox s SARA U-series (3G) or G series (2G) cellular modem module and a STM32F205 ARM Cortex M3 microcontroller. The Electron has a footprint, which is a drop-in compatible with the Particle Photon or Core. Pin Descriptions: VIN: This is the power supply pin to the Electron with a voltage range of 3.6 to 5.5VDC (internally regulated down to 3.3VDC). When the Electron is powered via its USB port, this pin will ouput a voltage of approximately 4.7VDC. Why 4.7 and not 5 Well, the actual voltage will be the USB voltage, which is normally 5, minus the forward voltage drop (0.3V) of the protection diode. RST: This is an active-low reset pin for the Electron. VBAT: Supply to the internal RTC, backup registers and SRAM (1.8 to 3.3VDC). 3V3: This pin is the output of the on-board regulator. When powering the Photon via VIN or the USB port, this pin will output a voltage of 3.3VDC. WKP: This is an active-high input that allows you to wakeup the module from sleep/deep sleep modes. When not used as a WAKEUP, this pin can also be used as a digital GPIO, ADC input or PWM. A0 - A5: These can be used as digital GPIOs, ADC inputs. Alternate functions include: SPI, PWM and DAC. B0 - B5: These can be used as digital GPIOs, partial ADC inputs, partial PWM outputs. C0 - C5: These can be used as digital GPIOs. D0 - D7: These can be used as digital GPIOs. Alternate functions include: UART, SPI, I2C, PWM and CAN. DAC: This pin can be used as a digital GPIO, ADC input or as a DAC ouput. RX: Primarily used as UART RX, but can also be used as a digital GPIO, ADC input or PWM. TX: Primarily used as UART TX, but can also be used as a digital GPIO, ADC input or PWM.