Adafruit’s latest RP2040 board is a compromise. It’s not as small as the QT Py RP2040 it is also not as feature rich as their Spring RP2040 but it does offer a great selection of GPIO pins in a compact form factor. The $10 ItsyBitsy RP2040 is ideal for those who need a lot of GPIO pins in a small package. Building on Adafruit’s line of ItsyBitsy boards, the RP2040 model brings the powerful Raspberry Pi RP2040 SoC to the form factor and from a distance you might think this is an Arduino Nano, the resemblance is striking.
ItsyBitsy RP2040 is about twice the size of QT Py RP2040, despite the same price. What we gain in GPIO pins, we lose in the form of a Stemma QT connector. The Feather RP2040 is larger than the ItsyBitsy RP2040, but only 14mm, not much for general projects, but for projects with limited space, every millimeter counts. Would the ItsyBitsy RP2040 be too far a compromise?
Adafruit ItsyBitsy RP2040 Hardware Specifications
|RP2040 SoC||ARM Cortex M0+ operates at a maximum of 133 Mhz|
|Flash storage||8MB QSPIA|
|GPIO||30 GPIO pins with the following functionality 16 x PWM outputs 10 x Digital I/O, 4 x Analog 12-bit ADC, 2 x I2C, SPI, 2 x UART, Programmable IO, 1 x NeoPixel|
|USB port||micro USB|
|Dimensions||1.4 x 0.7 x 0.2 (36mm x 18mm x 4mm)|
Design of the Adafruit ItsyBitsy RP2040
The ItsyBitsy range is a compromise, when you need a lot of pins for a project, but still need the smallest possible board. As Adafruit puts it, “What is smaller than a feather but bigger than a bauble? It’s an ItsyBitsy!”
In our case, the ItsyBitsy RP2040 is larger than the QT Py RP2040 but smaller than the Feather RP2040. The board is designed in a DIP configuration, which means it can be easily used in a breadboard. What’s missing from ItsyBitsy RP2040 are knurled edges for surface soldering, in fact there are five extra GPIO pins opposite the micro USB connector that need to be soldered with their pins facing up.
These extra pins are handy, but it means we don’t have Stemma QT connectors, these are usually not in the range. But their inclusion would have been a big connectivity boost for this little board. The GPIO pins are clearly labeled on both sides of the board, handy that the SDA and SCL pins for I2C have their GPIO pin numbers on the back.
Using the Adafruit ItsyBitsy RP2040
The ItsyBitsy RP2040 is classic Adafruit: easy to use and with a well-chosen selection of GPIO pins. Since this is an RP2040 board, we can write code using MicroPython, CircuitPython, C/C++ and the Arduino IDE. We tested the ItsyBitsy RP2040 with CircuitPython and MicroPython, but honestly, if you’re buying an Adafruit board, chances are you prefer CircuitPython.
In operation, the ItsyBitsy RP2040 behaves exactly like the QT Py RP2040 and the Feather RP2040. We did a few tests in CircuitPython, starting with the obligatory blinking LED and then driving the built-in NeoPixel. Although we don’t have a Stemma QT connector, we can use Stemma QT cards via a Stemma QT to jumper wire adapter and Adafruit’s extensive library of cards and drivers allows us to connect sensors, displays and many more expansion cards. Our testing with MicroPython involved using an I2C OLED screen to display images and animations. After a minor pin numbering issue that initially prevented us from using the I2C pins, we were able to resolve the issue and scroll through the Mujahid Tricks logo across the screen.
Usage scenarios for the Adafruit ItsyBitsy RP2040
ItsyBitsy RP2040 is designed for those who need a lot of GPIO pins in a small package. With the 13 GPIO pins of the QT Py RP2040 and the Stemma QT connector, we have a smaller package, but that limits what we can achieve, especially with Programmable IO (PIO) projects. The ItsyBitsy RP2040’s 30 GPIO pins allow us to mix projects that use traditional GPIO with PIO.
The size and GPIO selection of ItsyBitsy RP2040 means we can easily build robots and transfer sensor inputs, for example from an HC-SR04+ ultrasonic sensor to the PIO. With SPI and I2C we can attach screens, sensors and SD cards for data logging projects. The compromises made with the form factor are considered, cutting the wheat from the chaff and giving us exactly what we need.
At around $10, ItsyBitsy RP2040 is the same price as the QT Py RP2040and $2 cheaper than a Spring RP2040The Raspberry Pi Pico is the cheapest alternative, at just $4, but is larger and does not have a built-in Neopixel lamp (and only has 3 ADC ports). Every board works the same way, so it comes down to what you want to do with the board.
If you’re new to the RP2040 and prefer Adafruit’s boards, the Feather RP2040 is the best overall value. It has Stemma QT, onboard LiPo charging and compatibility with FeatherWing expansion cards. If you need the smallest possible board and can handle the loss of GPIO pins then QT Py RP2040 is for you. But if you need a compromise, the ItsyBitsy RP2040 is the solid choice.