Raspberry Pi Pico SDK Examples
Getting started
See Getting Started with the Raspberry Pi Pico and the README in the pico-sdk for information
on getting up and running.
First Examples
ADC
| App |
Description |
| hello_adc |
Display the voltage from an ADC input. |
| joystick_display |
Display a Joystick X/Y input based on two ADC inputs. |
| adc_console |
An interactive shell for playing with the ADC. Includes example of free-running capture mode. |
| onboard_temperature |
Display the value of the onboard temperature sensor. |
| microphone_adc |
Read analog values from a microphone and plot the measured sound amplitude. |
| dma_capture |
Use the DMA to capture many samples from the ADC. |
| read_vsys |
Demonstrates how to read VSYS to get the voltage of the power supply. |
Clocks
| App |
Description |
| hello_48MHz |
Change the system clock frequency to 48 MHz while running. |
| hello_gpout |
Use the general purpose clock outputs (GPOUT) to drive divisions of internal clocks onto GPIO outputs. |
| hello_resus |
Enable the clock resuscitate feature, "accidentally" stop the system clock, and show how we recover. |
| detached_clk_peri |
Detach peripheral clock and vary system clock. |
CMake
| App |
Description |
| build_variants |
Builds two version of the same app with different configurations |
DMA
| App |
Description |
| hello_dma |
Use the DMA to copy data in memory. |
| control_blocks |
Build a control block list, to program a longer sequence of DMA transfers to the UART. |
| channel_irq |
Use an IRQ handler to reconfigure a DMA channel, in order to continuously drive data through a PIO state machine. |
| sniff_crc |
Use the DMA engine's 'sniff' capability to calculate a CRC32 on a data buffer. |
Flash
| App |
Description |
| cache_perfctr |
Read and clear the cache performance counters. Show how they are affected by different types of flash reads. |
| nuke |
Obliterate the contents of flash. An example of a NO_FLASH binary (UF2 loaded directly into SRAM and runs in-place there). A useful utility to drag and drop onto your Pico if the need arises. |
| program |
Erase a flash sector, program one flash page, and read back the data. |
| xip_stream |
Stream data using the XIP stream hardware, which allows data to be DMA'd in the background whilst executing code from flash. |
| ssi_dma |
DMA directly from the flash interface (continuous SCK clocking) for maximum bulk read performance. |
GPIO
| App |
Description |
| hello_7segment |
Use the GPIOs to drive a seven segment LED display. |
| hello_gpio_irq |
Register an interrupt handler to run when a GPIO is toggled. |
| dht_sensor |
Use GPIO to bitbang the serial protocol for a DHT temperature/humidity sensor. |
See also: blink, blinking an LED attached to a GPIO.
HW divider
| App |
Description |
| hello_divider |
Show how to directly access the hardware integer dividers, in case AEABI injection is disabled. |
I2C
| App |
Description |
| bus_scan |
Scan the I2C bus for devices and display results. |
| bmp280_i2c |
Read and convert temperature and pressure data from a BMP280 sensor, attached to an I2C bus. |
| lcd_1602_i2c |
Display some text on a generic 16x2 character LCD display, via I2C. |
| lis3dh_i2c |
Read acceleration and temperature value from a LIS3DH sensor via I2C |
| mcp9808_i2c |
Read temperature, set limits and raise alerts when limits are surpassed. |
| mma8451_i2c |
Read acceleration from a MMA8451 accelerometer and set range and precision for the data. |
| mpl3115a2_i2c |
Interface with an MPL3115A2 altimeter, exploring interrupts and advanced board features, via I2C. |
| mpu6050_i2c |
Read acceleration and angular rate values from a MPU6050 accelerometer/gyro, attached to an I2C bus. |
| ssd1306_i2c |
Convert and display a bitmap on a 128x32 or 128x64 SSD1306-driven OLED display |
| pa1010d_i2c |
Read GPS location data, parse and display data via I2C. |
| pcf8523_i2c |
Read time and date values from a real time clock. Set current time and alarms on it. |
| ht16k33_i2c |
Drive a 4 digit 14 segment LED with an HT16K33. |
| slave_mem_i2c |
i2c slave example where the slave implements a 256 byte memory |
Interpolator
| App |
Description |
| hello_interp |
A bundle of small examples, showing how to access the core-local interpolator hardware, and use most of its features. |
Multicore
| App |
Description |
| hello_multicore |
Launch a function on the second core, printf some messages on each core, and pass data back and forth through the mailbox FIFOs. |
| multicore_fifo_irqs |
On each core, register and interrupt handler for the mailbox FIFOs. Show how the interrupt fires when that core receives a message. |
| multicore_runner |
Set up the second core to accept, and run, any function pointer pushed into its mailbox FIFO. Push in a few pieces of code and get answers back. |
Pico Board
| App |
Description |
| blinky |
Blink "hello, world" in Morse code on Pico's LED |
| button |
Use Pico's BOOTSEL button as a regular button input, by temporarily suspending flash access. |
Pico W Networking
These examples are for the Pico W, and are only available for PICO_BOARD=pico_w
FreeRTOS examples
These are examples of integrating Pico W networking under FreeRTOS, and require you to set the FREERTOS_KERNEL_PATH
to point to the FreeRTOS Kernel.
| App |
Description |
| picow_freertos_iperf_server_nosys |
Runs an "iperf" server for WiFi speed testing under FreeRTOS in NO_SYS=1 mode. The LED is blinked in another task |
| picow_freertos_iperf_server_sys |
Runs an "iperf" server for WiFi speed testing under FreeRTOS in NO_SYS=0 (i.e. full FreeRTOS integration) mode. The LED is blinked in another task |
| picow_freertos_ping_nosys |
Runs the lwip-contrib/apps/ping test app under FreeRTOS in NO_SYS=1 mode. |
| picow_freertos_ping_sys |
Runs the lwip-contrib/apps/ping test app under FreeRTOS in NO_SYS=0 (i.e. full FreeRTOS integration) mode. The test app uses the lwIP socket API in this case. |
Pico W Bluetooth
These examples are for the Pico W, and are only available for PICO_BOARD=pico_w.
They are examples from the Blue Kitchen Bluetooth stack, see here for a full description.
By default, the Bluetooth examples are only built in one "mode" only (background, poll, or freertos), with the
default being background. This can be changed by passing -DBTSTACK_EXAMPLE_TYPE=poll etc. to CMake, or all
examples can be built (which may be slow) by passing -DBTSTACK_EXAMPLE_TYPE=all
Freertos versions can only be built if FREERTOS_KERNEL_PATH is defined.
Some Standalone Bluetooth examples (without all the common example build infrastructure) are also available:
PIO
| App |
Description |
| hello_pio |
Absolutely minimal example showing how to control an LED by pushing values into a PIO FIFO. |
| apa102 |
Rainbow pattern on on a string of APA102 addressable RGB LEDs. |
| clocked_input |
Shift in serial data, sampling with an external clock. |
| differential_manchester |
Send and receive differential Manchester-encoded serial (BMC). |
| hub75 |
Display an image on a 128x64 HUB75 RGB LED matrix. |
| i2c |
Scan an I2C bus. |
| ir_nec |
Sending and receiving IR (infra-red) codes using the PIO. |
| logic_analyser |
Use PIO and DMA to capture a logic trace of some GPIOs, whilst a PWM unit is driving them. |
| manchester_encoding |
Send and receive Manchester-encoded serial. |
| onewire |
A library for interfacing to 1-Wire devices, with an example for the DS18B20 temperature sensor. |
| pio_blink |
Set up some PIO state machines to blink LEDs at different frequencies, according to delay counts pushed into their FIFOs. |
| pwm |
Pulse width modulation on PIO. Use it to gradually fade the brightness of an LED. |
| spi |
Use PIO to erase, program and read an external SPI flash chip. A second example runs a loopback test with all four CPHA/CPOL combinations. |
| squarewave |
Drive a fast square wave onto a GPIO. This example accesses low-level PIO registers directly, instead of using the SDK functions. |
| st7789_lcd |
Set up PIO for 62.5 Mbps serial output, and use this to display a spinning image on a ST7789 serial LCD. |
| quadrature_encoder |
A quadrature encoder using PIO to maintain counts independent of the CPU. |
| uart_rx |
Implement the receive component of a UART serial port. Attach it to the spare Arm UART to see it receive characters. |
| uart_tx |
Implement the transmit component of a UART serial port, and print hello world. |
| ws2812 |
Examples of driving WS2812 addressable RGB LEDs. |
| addition |
Add two integers together using PIO. Only around 8 billion times slower than Cortex-M0+. |
PWM
| App |
Description |
| hello_pwm |
Minimal example of driving PWM output on GPIOs. |
| led_fade |
Fade an LED between low and high brightness. An interrupt handler updates the PWM slice's output level each time the counter wraps. |
| measure_duty_cycle |
Drives a PWM output at a range of duty cycles, and uses another PWM slice in input mode to measure the duty cycle. |
Reset
| App |
Description |
| hello_reset |
Perform a hard reset on some peripherals, then bring them back up. |
RTC
| App |
Description |
| hello_rtc |
Set a date/time on the RTC, then repeatedly print the current time, 10 times per second, to show it updating. |
| rtc_alarm |
Set an alarm on the RTC to trigger an interrupt at a date/time 5 seconds into the future. |
| rtc_alarm_repeat |
Trigger an RTC interrupt once per minute. |
SPI
| App |
Description |
| bme280_spi |
Attach a BME280 temperature/humidity/pressure sensor via SPI. |
| mpu9250_spi |
Attach a MPU9250 accelerometer/gyoscope via SPI. |
| spi_dma |
Use DMA to transfer data both to and from the SPI simultaneously. The SPI is configured for loopback. |
| spi_flash |
Erase, program and read a serial flash device attached to one of the SPI controllers. |
| spi_master_slave |
Demonstrate SPI communication as master and slave. |
| max7219_8x7seg_spi |
Attaching a Max7219 driving an 8 digit 7 segment display via SPI |
| max7219_32x8_spi |
Attaching a Max7219 driving an 32x8 LED display via SPI |
System
| App |
Description |
| hello_double_tap |
An LED blink with the pico_bootsel_via_double_reset library linked. This enters the USB bootloader when it detects the system being reset twice in quick succession, which is useful for boards with a reset button but no BOOTSEL button. |
| narrow_io_write |
Demonstrate the effects of 8-bit and 16-bit writes on a 32-bit IO register. |
| unique_board_id |
Read the 64 bit unique ID from external flash, which serves as a unique identifier for the board. |
Timer
| App |
Description |
| hello_timer |
Set callbacks on the system timer, which repeat at regular intervals. Cancel the timer when we're done. |
| periodic_sampler |
Sample GPIOs in a timer callback, and push the samples into a concurrency-safe queue. Pop data from the queue in code running in the foreground. |
| timer_lowlevel |
Example of direct access to the timer hardware. Not generally recommended, as the SDK may use the timer for IO timeouts. |
UART
| App |
Description |
| hello_uart |
Print some text from one of the UART serial ports, without going through stdio. |
| lcd_uart |
Display text and symbols on a 16x02 RGB LCD display via UART |
| uart_advanced |
Use some other UART features like RX interrupts, hardware control flow, and data formats other than 8n1. |
USB Device
TinyUSB Examples
Most of the USB device examples come directly from the TinyUSB device examples directory here.
Those that are supported on RP2040 devices are automatically included as part of the pico-examples
build as targets named tinyusb_dev_<example_name>, e.g. https://github.com/hathach/tinyusb/tree/master/examples/device/hid_composite
is built as tinyusb_dev_hid_composite.
At the time of writing, these examples are available:
- tinyusb_dev_audio_4_channel_mic
- tinyusb_dev_audio_test
- tinyusb_dev_board_test
- tinyusb_dev_cdc_dual_ports
- tinyusb_dev_cdc_msc
- tinyusb_dev_dfu
- tinyusb_dev_dfu_runtime
- tinyusb_dev_dynamic_configuration
- tinyusb_dev_hid_composite
- tinyusb_dev_hid_generic_inout
- tinyusb_dev_hid_multiple_interface
- tinyusb_dev_midi_test
- tinyusb_dev_msc_dual_lun
- tinyusb_dev_net_lwip_webserver
- tinyusb_dev_uac2_headset
- tinyusb_dev_usbtmc
- tinyusb_dev_video_capture
- tinyusb_dev_webusb_serial
Whilst these examples ably demonstrate how to use TinyUSB in device mode, their CMakeLists.txt is set up in a way
tailored to how TinyUSB builds their examples within their source tree.
For a better example of how to configure CMakeLists.txt for using TinyUSB in device mode with the Raspberry Pi SDK
see below:
SDK build example
| App |
Description |
| dev_hid_composite |
A copy of the TinyUSB device example with the same name, but with a CMakeLists.txt which demonstrates how to add a dependency on the TinyUSB device libraries with the Raspberry Pi Pico SDK |
Low Level example
| App |
Description |
| dev_lowlevel |
A USB Bulk loopback implemented with direct access to the USB hardware (no TinyUSB) |
USB Host
All the USB host examples come directly from the TinyUSB host examples directory here.
Those that are supported on RP2040 devices are automatically included as part of the pico-examples
build as targets named tinyusb_host_<example_name>, e.g. https://github.com/hathach/tinyusb/tree/master/examples/host/cdc_msc_hid
is built as tinyusb_host_cdc_msc_hid.
At the time of writing, there is only one host example available:
USB Dual Mode
USB Dual Mode uses PIO as a USB host controller and the RP2040 USB device controller as a device controller. All the USB dual examples come directly from the TinyUSB dual examples directory here.
Those that are supported on RP2040 devices are automatically included as part of the pico-examples
build as targets named tinyusb_dual_<example_name>, e.g. https://github.com/hathach/tinyusb/tree/master/examples/dual/host_hid_to_device_cdc
is built as tinyusb_dual_host_hid_to_device_cdc.
At the time of writing, there is only one dual example available:
- tinyusb_dual_host_hid_to_device_cdc
Watchdog
| App |
Description |
| hello_watchdog |
Set the watchdog timer, and let it expire. Detect the reboot, and halt. |
