I/O1 Xplained Pro implements one standard Xplained Pro extension header marked with EXT in silkscreen. This header makes it possible to connect the board to any Xplained Pro MCU board. The pin-out definition for the extension header can be seen in the table below.
| Pin on EXT | Function | Description |
|---|---|---|
| 1 | ID | Communication line to ID chip |
| 2 | GND | Ground |
| 3 | LIGHTSENSOR | Light sensor output (ADC) |
| 4 | LP_OUT | Low pass filter output (ADC) |
| 5 | GPIO1 | General Purpose I/O pin (GPIO) |
| 6 | GPIO2 | General Purpose I/O pin (GPIO) |
| 7 | LED | LED control (PWM) |
| 8 | LP_IN | Low pass filter input (PWM) |
| 9 | TEMP_ALERT | ALERT pin (Pin 3) of temperature sensor chip (IRQ) |
| 10 | microSD_DETECT | Detect pin on microSD card connector (GPIO) |
| 11 | TWI SDA | Data line of TWI interface, connected to SDA pin (Pin 1) of temperature sensor chip |
| 12 | TWI SCL | Clock line of TWI interface, connected to SCL pin (Pin 2) of temperature sensor chip |
| 13 | UART RX | Receive pin of target MCU UART interface |
| 14 | UART TX | Transmit pin of target MCU UART interface |
| 15 | microSD_SS | Chip select signal, connected to DAT3 pin on microSD card connector |
| 16 | SPI_MOSI | Master Out, Slave In signal of target MCU SPI interface. Connected to CMD pin on microSD card connector. |
| 17 | SPI_MISO | Master In, Slave Out signal of target MCU SPI interface. Connected to D0 pin on microSD card connector. |
| 18 | SPI_SCK | Clock line of SPI interface. Connected to CLK pin on microSD card connector. |
| 19 | GND | Ground |
| 20 | VCC | Target supply voltage |