The nRF9160 DK has an I/O expander that can optionally be used to interface the LEDs, slide switches, and buttons.
The connection of each component is controlled by the nRF52840 System on Chip (SoC) using analog switches (see Switches for buttons and LEDs). The I/O expander is enabled by the nRF52840 SoC, see Switches for I/O expander for more information. When the I/O expander is enabled, the I/O expander is interfaced by the nRF9160 General-Purpose Input/Output (GPIO)s shown in the following table.
| Signal | GPIO | Description |
|---|---|---|
| SDA | P0.30 | I2C data line |
| SCL | P0.31 | I2C clock line |
| IOEXP_IRQ | P0.06 | Interrupt line from the I/O expander |
The following table shows the I/O expander connections:
| Component | I/O expander pin |
|---|---|
| LED 1 | I/O_EXP_IO4 |
| LED 2 | I/O_EXP_IO5 |
| LED 3 | I/O_EXP_IO6 |
| LED 4 | I/O_EXP_IO7 |
| Switch 1 | I/O_EXP_IO2 |
| Switch 2 | I/O_EXP_IO3 |
| Button 1 | I/O_EXP_IO0 |
| Button 2 | I/O_EXP_IO1 |
Figure 1. I/O expander
