3.3.1 Xplained Pro Standard Extension Headers
All Xplained Pro kits have dual row, 20-pin 100-mil extension headers. The Xplained Pro MCU boards have male headers while the Xplained Pro extensions have the female counterparts. The following table provides the pin description for all the connected pins.
Note: Not all pins are always connected
on all extension headers.
The extension headers can be used to connect a variety of Xplained Pro extensions to Xplained Pro MCU boards or to access the pins of the target microcontroller on the Xplained Pro boards.
| Pin Number | Pin Name | Description |
| 1 | ID | Pin to communicate with the ID chip on an extension board |
| 2 | GND | Ground |
| 3 | ADC(+) | Analog-to-Digital Converter (ADC); alternatively, a pin for the positive terminal of a differential ADC |
| 4 | ADC(-) | Analog-to-Digital Converter; alternatively, a pin for the negative terminal of a differential ADC |
| 5 | GPIO1 | General purpose I/O pin |
| 6 | GPIO2 | General purpose I/O pin |
| 7 | PWM(+) | Pulse Width Modulation (PWM); alternatively, a pin for the positive part of a differential PWM |
| 8 | PWM(-) | Pulse Width Modulation; alternatively, a pin for the negative part of a differential PWM |
| 9 | IRQ/GPIO | Interrupt request pin and/or general purpose I/O pin |
| 10 | SPI_SS_B/ GPIO | Client select pin for Serial Peripheral Interface (SPI) and/or general purpose I/O pin |
| 11 | I2C_SDA | Data pin for I2C interface. Always connected, bus type |
| 12 | I2C_SCL | Clock pin for I2C interface. Always connected, bus type |
| 13 | UART_RX | Receiver pin of target device UART |
| 14 | UART_TX | Transmitter pin of target device UART |
| 15 | SPI_SS_A | Client select for the Serial Peripheral Interface (SPI). This pin should preferably not be connected to anything else |
| 16 | SPI_MOSI | SPI host out, client in pin. Always connected, bus type |
| 17 | SPI_MISO | SPI host in, client out pin. Always connected, bus type |
| 18 | SPI_SCK | SPI clock pin. Always connected, bus type |
| 19 | GND | Ground pin for extension boards |
| 20 | VCC | Power pin for extension boards |