This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

Adafruit KB2040

Overview

The Adafruit KB2040 is a small, low-cost, versatile board from Adafruit. It is equipped with an RP2040 SoC, an on-board RGB Neopixel, a USB connector, and a STEMMA QT connector. The USB bootloader allows it to be flashed without any adapter, in a drag-and-drop manner.

Hardware

  • Dual core Arm Cortex-M0+ processor running up to 133MHz

  • 264KB on-chip SRAM

  • 8MB on-board QSPI flash with XIP capabilities

  • 18 GPIO pins

  • 4 Analog inputs

  • 1 UART peripherals

  • 1 SPI controllers

  • 2 I2C controllers (one via STEMMA QT connector)

  • 16 PWM channels

  • USB 1.1 controller (host/device)

  • 8 Programmable I/O (PIO) for custom peripherals

  • On-board RGB LED

  • 1 Watchdog timer peripheral

Adafruit KB2040

Fig. 76 Adafruit KB2040 (Image courtesy of Adafruit)

Supported Features

The adafruit_kb2040 board configuration supports the following hardware features:

Peripheral

Kconfig option

Devicetree compatible

NVIC

N/A

arm,v6m-nvic

UART

CONFIG_SERIAL

raspberrypi,pico-uart

GPIO

CONFIG_GPIO

raspberrypi,pico-gpio

ADC

CONFIG_ADC

raspberrypi,pico-adc

I2C

CONFIG_I2C

snps,designware-i2c

SPI

CONFIG_SPI

raspberrypi,pico-spi

USB Device

CONFIG_USB_DEVICE_STACK

raspberrypi,pico-usbd

HWINFO

CONFIG_HWINFO

N/A

Watchdog Timer (WDT)

CONFIG_WATCHDOG

raspberrypi,pico-watchdog

PWM

CONFIG_PWM

raspberrypi,pico-pwm

Pin Mapping

The peripherals of the RP2040 SoC can be routed to various pins on the board. The configuration of these routes can be modified through DTS. Please refer to the datasheet to see the possible routings for each peripheral.

Default Zephyr Peripheral Mapping:

  • UART0_TX : P0

  • UART0_RX : P1

  • I2C1_SDA : P2

  • I2C1_SCL : P3

  • SPI0_RX : P20

  • SPI0_SCK : P18

  • SPI0_TX : P19

Programming and Debugging

Flashing

Using UF2

Since it doesn’t expose the SWD pins, you must flash the Adafruit KB2040 with a UF2 file. By default, building an app for this board will generate a build/zephyr/zephyr.uf2 file. If the KB2040 is powered on with the BOOTSEL button pressed, it will appear on the host as a mass storage device. The UF2 file should be drag-and-dropped to the device, which will flash the KB2040.