STEPico

RP2040 based micro-controller with Type C connector and 4 full color LEDs

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Features

STEPico Core is a low-cost but high-performance miniature development board designed based on the microcontroller RP2040 launched by Raspberry Pi. STEPico Core reserves the full compatibility to the original PICO2040, with further improvements that the original Micro-USB connector was replaced by Type C, and 4 full color LEDs, a power light indicator and a hardware reset button were added on-board for easier debugging purposes. A series of extension boards and kits were also developed and can be found in STEPico series products.

General Functions

In general, the STEPico Core board is fully compatible with PICO2040 in terms of the pin functions, except that the MicroUSB was replaced to Type C and some buttons and LEDs were added making the board more user friendly for debugging. The pin diagram of STEPico-Core is shown:

General Pin Diagram and Functional Blocks of STEPico

Power up the Board

Powering STEPico-Core is same as PICO2040, for which you may use either way as indicated:

The Four LEDs on Board

Comparing to PICO2040 which uses RT6150 to convert the 5V USB to 3.3V and occupied GPIO23 to control the PWM/PFM mode of the DC-DC converter (details can be found in PICO datasheet section 4.3 and 4.4), the STEPico-Core uses SGM6012 DC-DC converter and the extra left GPIO23 was used to control the four LEDs on board. See the Schematic of the board.

Technical Specifications

Electrical Parameters

Parameter	Specs
Microcontroller	RP2040
Processor	Dual-core Arm Cortex-M0+
Clock Speed	133MHz
Supply Voltage	1.8-5.5V
Working Temperature	-20C to 85C
On-chip SRAM	264KB
On-board QSPI Flash	2MB
Communication Ports	UART x 2; SPI x 2; I2C x 2
GPIOs	26 (including 3 ADC channels)
PWM Channels	16
PIO Channels	8
Power saving modes	Sleep/dormant
Sensors	Temperature
Footprint	DIP40/stampholes

Hardware Design

The schematic of STEPico is shown in the figure below:

The main parts used on this board is listed in the Table.

ID	Main part used	Descriptions
U1	RP2040	Microcontroller of the board
U2	SGM6012	5 to 3.3V DC-DC converter
U3	P25Q16H	Serial interface flash memory
D4-D7	WS2812B	Integrated full color LED
Q1	SI2302	N-Channel MOSFET

Dimensions

Referring to the following dimensions in case you would like to design an enclosure for the board; all quantities are in milimeters.

Software Development Kit

STEPico is designed based on RP2040 microcontroller and the board was configured to be fully compatible with all software development kits (SDK) and utilities specified in Raspberry Pi Pico product page:

Raspberry Pi Documentation - Raspberry Pi Pico and Pico WRaspberry_Pi

If you are new to microcontrollers and embedded programming, we recommend using Python SKD as a quick and easy kick start. A concise and detailed tutorial for Python and RP2040 can be found in this document:

The board also supports C/C++ SDK, available at this document.

Board Configuration

Both our STEPico and Raspberry Pi Pico use the same RP2040 as the core chip therefore you can simply follow the same procedures while figuring out the initial board setup.

This tutorial is tailored for Windows users. For those using different operating systems, there are numerous guides readily available via a quick Google or YouTube search

Please follow the following quick steps to configure the board.

Start by downloading and installing Thonny, which is an integrated development environment (IDE) that makes it easy to write and run code.

STEP 1: Install Thonny

You can download Thonny from the official website (https://thonny.org/) and follow the installation instructions for your operating system.

STEP 2: Connect the board to USB

Now, take your STEPico board and connect it to your computer using a USB cable. Make sure the board is properly connected and powered on.

Step 3: Set the STEPico in Bootloader Mode

To program the STEPico, you need to put it in bootloader mode. This mode allows you to transfer your code to the board. To do this, press and hold the BOOT button on your STEPico board (the button is usually labeled as "BOOT" or "SW1"). While holding the button, press the RUN button on the board (labeled as "RESET," "SW2," or “RUN”). Release the BOOTSEL button.

Step 4: STEPico Appears as a Drive

After entering bootloader mode, your STEPico will appear as a removable drive on your “This PC” found in the file explorer. It may be named "RPI-RP2" or something similar. Open the drive.

Step 5: Download MicroPython

Visit the MicroPython website (https://micropython.org/download/rp2-pico/) and download the latest "uf2" file for the STEPico.

Step 6: Transfer MicroPython to the STEPico

Locate the downloaded "uf2" file and drag it to the STEPico drive that appeared in step 4. This will transfer the MicroPython firmware to the board.

Step 7: STEPico Reboots

After transferring the MicroPython firmware, the STEPico board will reboot automatically. Wait a few seconds for the reboot to complete. The device should no longer show up under devices and drives.

Step 8: Open Thonny

Open the Thonny IDE that you installed in step 1. It should detect the STEPico board automatically.

Step 9: Select Board and Serial Port

In Thonny, go to the "Tools" menu and select "Options." Under the "Interpreter" tab, choose "MicroPython (RP2040)" as the board. Then, select the correct serial port (port number may vary) for your RP2040 board. Click "OK" to save the settings.

Step 10: Write and Run Code

Now you're ready to write and run code on your STEPico! In the Thonny editor, start writing your MicroPython code. When saving the code, there will be an option to save locally on your PC or directly onto the STEPico.

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