Pimoroni Tiny2040

The Tiny2040 is a general purpose RP2040 board supplied by Pimoroni.

../../../../../_images/Tiny2040.png

The Pimoroni Tiny 2040 has two buttons (RESET and BOOT) allowing to boot from ROM without disconnecting the device.

See the Pimoroni website for information about the Pimoroni Tiny 2040.

Features

  • RP2040 microcontroller chip

  • Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz

  • 264kB of SRAM, and 2MB or 8MB of on-board Flash memory

  • Castellated module allows soldering direct to carrier boards

  • USB Host and Device support via type C connector

  • Low-power sleep and dormant modes

  • Drag & drop programming using mass storage over USB

  • 12 multi-function GPIO pins

  • 2× SPI, 2× I2C, 2× UART, 3× 12-bit ADC, 16× controllable PWM channels

  • Accurate clock and timer on-chip

  • Temperature sensor

  • Accelerated floating point libraries on-chip

  • 8 × Programmable IO (PIO) state machines for custom peripheral support

Serial Console

By default a serial console appears on pins 15 (RX GPIO0) and pin 16 (TX GPIO1). This console runs a 115200-8N1.

The board can be configured to use the USB connection as the serial console.

Buttons and LEDs

There is a single onboard RGB LED controlled by pins GPIO18 (red), GPIO19 (green), and GPIO20 (blue).

The is a User/BOOT button readable as GPIO23. If held down when power is first applied the RP2040 will boot into program mode and appear to a computer connected via USB as a storage device. Saving a .UF2 file to this device will replace the Flash ROM contents on the RP2040.

Pin Mapping

Pads numbered anticlockwise from USB connector.

Pad

Signal

Notes

1

VBUS

Connected to USB +5V

2

Ground

3

3V3

Out to peripherals

4

GPIO29

ADC3

5

GPIO28

ADC2

6

GPIO27

ADC1

7

GPIO26

ADC0

8

Ground

9

GPIO7

10

GPIO6

11

GPIO5

12

GPIO4

13

GPIO3

14

GPIO2

15

GPIO1

Default RX for UART0 serial console

16

GPIO0

Default TX for UART0 serial console

Power Supply

The Raspberry Pi Pico can be powered via the USB connector, or by supplying +5V to pin 1.

The Raspberry Pi Pico chip run on 3.3 volts. This is supplied by an onboard voltage regulator.

Supported Capabilities

NuttX supports the following RP2040 capabilities:

  • UART (console port)

    • GPIO 0 (UART0 TX) and GPIO 1 (UART0 RX) are used for the console.

  • I2C

  • SPI (master only)

  • DMAC

  • PWM

  • ADC

  • Watchdog

  • USB device

    • MSC, CDC/ACM serial and these composite device are supported.

    • CDC/ACM serial device can be used for the console.

  • PIO (RP2040 Programmable I/O)

  • Flash ROM Boot

  • SRAM Boot

    • If Pico SDK is available, nuttx.uf2 file which can be used in BOOTSEL mode will be created.

  • Persistent flash filesystem in unused flash ROM

  • WiFi wireless communication

There is currently no direct user mode access to these RP2040 hardware features:

  • SPI Slave Mode

  • SSI

  • RTC

  • Timers

NuttX also provide support for these external devices:

  • WS2812 smart pixel support

Installation

  1. Download Raspberry Pi Pico SDK

$ git clone -b 2.0.0 https://github.com/raspberrypi/pico-sdk.git

  1. Download and install picotool

Instructions can be found here: https://github.com/raspberrypi/picotool

If you are on Arch Linux, you can install the picotool through the AUR:

$ yay -S picotool

  1. Set PICO_SDK_PATH environment variable

$ export PICO_SDK_PATH=<absolute_path_to_pico-sdk_directory>

  1. Configure and build NuttX

$ git clone https://github.com/apache/nuttx.git nuttx
$ git clone https://github.com/apache/nuttx-apps.git apps
$ cd nuttx
$ make distclean
$ ./tools/configure.sh pimoroni-tiny2040:nsh
$ make V=1

  1. Connect Pimoroni Tiny 2040 board to USB port. While pressing the BOOT button, shortly press the RESET button. On releasing the BOOT button the board boots from internal ROM and will be detected as USB Mass Storage Device. Then copy “nuttx.uf2” into the device. (Same manner as the standard Pico SDK applications installation.)

  2. To access the console, GPIO 0 and 1 pins must be connected to the device such as USB-serial converter.

    usbnsh configuration provides the console access by USB CDC/ACM serial decive. The console is available by using a terminal software on the USB host.

Configurations

composite

NuttShell configuration (console enabled in UART0, at 115200 bps) with support for CDC/ACM with MSC USB composite driver. conn command enables the composite device.

gpio

NuttShell configuration (console enabled in UART0, at 115200 bps) with GPIO examples.

GPIO pin options

GPIO

Function

GPIO18

Onboard RGB LED (red, out)

GPIO19

Onboard RGB LED (green, out)

GPIO20

Onboard RGB LED (blue, out)

GPIO23

Onboard BOOT button (user)

No interrupt pin configured.

nsh

Basic NuttShell configuration (console enabled in UART0, at 115200 bps).

nsh-flash

Basic NuttShell configuration (console enabled in UART0, at 115200 bps with SMART flash filesystem.

nshsram

NuttShell configuration (console enabled in UART0, at 115200 bps) with interrupt vectors in RAM.

smp

Basic NuttShell configuration (console enabled in UART0, at 115200 bps) with both ARM cores enabled.

spisd

NuttShell configuration (console enabled in UART0, at 115200 bps) with SPI SD card support enabled.

spisd connections

SD card slot

Pimoroni Tiny 2040

DAT2

Not connected

DAT3/CS

GP5 (SPI0 CSn) (Pin 11)

CMD /DI

GP7 (SPI0 TX) (Pin 9)

VDD

3V3 OUT (Pin 3)

CLK/SCK

GP6 (SPI0 SCK) (Pin 10)

VSS

GND (Pin 2 or 8)

DAT0/DO

GP4 (SPI0 RX) (Pin 12)

DAT1

Not connected

Card hot swapping is not supported.

usbmsc

NuttShell configuration (console enabled in UART0, at 115200 bps) with support for USB MSC and CDC/ACM.

msconn and sercon commands enable the MSC and CDC/ACM devices. The MSC support provides the interface to the SD card with SPI, so the SD card slot connection like spisd configuration is required.

usbnsh

Basic NuttShell configuration using CDC/ACM serial (console enabled in USB Port, at 115200 bps).

License exceptions

The following files are originated from the files in Pico SDK. So, the files are licensed under 3-Clause BSD same as Pico SDK.

  • arch/arm/src/rp2040/rp2040_clock.c

  • arch/arm/src/rp2040/rp2040_pll.c

  • arch/arm/src/rp2040/rp2040_xosc.c

    • These are created by referring the Pico SDK clock initialization.

  • arch/arm/src/rp2040/rp2040_pio.c

  • arch/arm/src/rp2040/rp2040_pio.h

  • arch/arm/src/rp2040/rp2040_pio_instructions.h

    • These provide the similar APIs to Pico SDK’s hardware_pio APIs.

  • arch/arm/src/rp2040/hardware/*.h

    • These are generated from rp2040.svd originally provided in Pico SDK.