NRF52840
The Arduino 33 BLE uses the NRF52840 chip as its core processor. The Arduino core software is implemented over the top of the Mbed OS. While this allows you to use (all?) the Mbed functions, it can cause confusion over the naming of the pins.
For normal Arduino stuff, just use the familiar pin names. When using Mbed fuctions and features though, you will want to use the actual pin names.
You can find information and documents at the Arduino project page
This table lists the equivalences.
| Arduino Pins | Mbed name |
|---|---|
| D0/TX | P1_3 (not recommended for use) |
| D1/RX | P1_10 (not recommended for use) |
| D2 | P1_11 |
| D3 | P1_12 |
| D4 | P1_15 |
| D5 | P1_13 |
| D6 | P1_14 |
| D7 | P1_23 |
| D8 | P1_21 |
| D9 | P1_27 |
| D10 | P1_2 |
| D11 | P1_1 |
| D12 | P1_8 |
| D13/LED_BUILTIN | P0_13 |
| A0 | P0_4 |
| A1 | P0_5 |
| A2 | P0_30 |
| A3 | P0_29 |
| A4 | P0_31 |
| A5 | P0_2 |
| A6 | P0_28 |
| A7 | P0_3 |
| LED_PWR | P1_9 |
| LEDR | P0_24 (RGB LED Red ) |
| LEDG | P0_16 (RGB LED Green ) |
| LEDB | P0_06 (RGB LED Blue ) |
Here is a picture:
